diff --git a/internal/lib/config.go b/config/config.go
similarity index 94%
rename from internal/lib/config.go
rename to config/config.go
index bf06cdb..379d3b1 100644
--- a/internal/lib/config.go
+++ b/config/config.go
@@ -1,4 +1,4 @@
-package lib
+package config
 
 type Config struct {
 	Env         string `env:"ENV" env-default:"prod"`
diff --git a/go.mod b/go.mod
index ec94a67..41b084a 100644
--- a/go.mod
+++ b/go.mod
@@ -35,6 +35,7 @@ require (
 	github.com/rcrowley/go-metrics v0.0.0-20200313005456-10cdbea86bc0 // indirect
 	github.com/sirupsen/logrus v1.9.3 // indirect
 	github.com/tchap/go-patricia/v2 v2.3.1 // indirect
+	github.com/valkey-io/valkey-go v1.0.47 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
 	github.com/yashtewari/glob-intersection v0.2.0 // indirect
@@ -46,7 +47,7 @@ require (
 	golang.org/x/crypto v0.25.0 // indirect
 	golang.org/x/net v0.27.0 // indirect
 	golang.org/x/sync v0.7.0 // indirect
-	golang.org/x/sys v0.22.0 // indirect
+	golang.org/x/sys v0.24.0 // indirect
 	golang.org/x/text v0.16.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240701130421-f6361c86f094 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
diff --git a/go.sum b/go.sum
index 0c89821..e264c7b 100644
--- a/go.sum
+++ b/go.sum
@@ -127,6 +127,8 @@ github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsT
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/tchap/go-patricia/v2 v2.3.1 h1:6rQp39lgIYZ+MHmdEq4xzuk1t7OdC35z/xm0BGhTkes=
 github.com/tchap/go-patricia/v2 v2.3.1/go.mod h1:VZRHKAb53DLaG+nA9EaYYiaEx6YztwDlLElMsnSHD4k=
+github.com/valkey-io/valkey-go v1.0.47 h1:fW5+m2BaLAbxB1EWEEWmj+i2n+YcYFBDG/jKs6qu5j8=
+github.com/valkey-io/valkey-go v1.0.47/go.mod h1:BXlVAPIL9rFQinSFM+N32JfWzfCaUAqBpZkc4vPY6fM=
 github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb h1:zGWFAtiMcyryUHoUjUJX0/lt1H2+i2Ka2n+D3DImSNo=
 github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
 github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 h1:EzJWgHovont7NscjpAxXsDA8S8BMYve8Y5+7cuRE7R0=
@@ -168,6 +170,8 @@ golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
 golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
+golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
 golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
 golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d h1:vU5i/LfpvrRCpgM/VPfJLg5KjxD3E+hfT1SH+d9zLwg=
diff --git a/internal/contests/delivery.go b/internal/contests/delivery.go
new file mode 100644
index 0000000..b1d0091
--- /dev/null
+++ b/internal/contests/delivery.go
@@ -0,0 +1,4 @@
+package contests
+
+type ContestHandlers interface {
+}
diff --git a/internal/contests/delivery/grpc/handlers.go b/internal/contests/delivery/grpc/handlers.go
new file mode 100644
index 0000000..21e034e
--- /dev/null
+++ b/internal/contests/delivery/grpc/handlers.go
@@ -0,0 +1 @@
+package grpc
diff --git a/internal/contests/pg_repository.go b/internal/contests/pg_repository.go
new file mode 100644
index 0000000..4085d03
--- /dev/null
+++ b/internal/contests/pg_repository.go
@@ -0,0 +1,13 @@
+package contests
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+)
+
+type ContestRepository interface {
+	CreateContest(ctx context.Context, contest *models.Contest) (int32, error)
+	ReadContestById(ctx context.Context, id int32) (*models.Contest, error)
+	UpdateContest(ctx context.Context, contest *models.Contest) error
+	DeleteContest(ctx context.Context, id int32) error
+}
diff --git a/internal/storage/participants.go b/internal/contests/repository/participants.go
similarity index 98%
rename from internal/storage/participants.go
rename to internal/contests/repository/participants.go
index e703e18..99ab645 100644
--- a/internal/storage/participants.go
+++ b/internal/contests/repository/participants.go
@@ -1,4 +1,4 @@
-package storage
+package repository
 
 import (
 	"context"
diff --git a/internal/contests/repository/pg_repository.go b/internal/contests/repository/pg_repository.go
new file mode 100644
index 0000000..00e214b
--- /dev/null
+++ b/internal/contests/repository/pg_repository.go
@@ -0,0 +1,97 @@
+package repository
+
+import (
+	"context"
+	"errors"
+	"git.sch9.ru/new_gate/models"
+	"git.sch9.ru/new_gate/ms-tester/pkg/utils"
+	"github.com/jackc/pgerrcode"
+	"github.com/jackc/pgx/v5/pgconn"
+	"github.com/jmoiron/sqlx"
+	"go.uber.org/zap"
+)
+
+type ContestRepository struct {
+	db     *sqlx.DB
+	logger *zap.Logger
+}
+
+func NewContestRepository(db *sqlx.DB, logger *zap.Logger) *ContestRepository {
+	return &ContestRepository{
+		db:     db,
+		logger: logger,
+	}
+}
+
+func (r *ContestRepository) CreateContest(ctx context.Context, contest *models.Contest) (int32, error) {
+	query := r.db.Rebind(`
+INSERT INTO contests
+    (name)
+VALUES (?)
+RETURNING id
+`)
+
+	rows, err := r.db.QueryxContext(
+		ctx,
+		query,
+		contest.Name,
+	)
+	if err != nil {
+		return 0, handlePgErr(err)
+	}
+
+	defer rows.Close()
+	var id int32
+	err = rows.StructScan(&id)
+	if err != nil {
+		return 0, handlePgErr(err)
+	}
+
+	return id, nil
+
+}
+
+func (r *ContestRepository) ReadContestById(ctx context.Context, id int32) (*models.Contest, error) {
+	var contest models.Contest
+	query := r.db.Rebind("SELECT * from contests WHERE id=? LIMIT 1")
+	err := r.db.GetContext(ctx, &contest, query, id)
+	if err != nil {
+		return nil, handlePgErr(err)
+	}
+	return &contest, nil
+}
+
+func (r *ContestRepository) UpdateContest(ctx context.Context, contest *models.Contest) error {
+	query := r.db.Rebind("UPDATE contests SET name=? WHERE id=?")
+	_, err := r.db.ExecContext(ctx, query, contest.Name, contest.Id)
+	if err != nil {
+		return handlePgErr(err)
+	}
+
+	return nil
+}
+
+func (r *ContestRepository) DeleteContest(ctx context.Context, id int32) error {
+	query := r.db.Rebind("DELETE FROM contests WHERE id=?")
+	_, err := r.db.ExecContext(ctx, query, id)
+	if err != nil {
+		return handlePgErr(err)
+	}
+
+	return nil
+}
+
+func handlePgErr(err error) error {
+	var pgErr *pgconn.PgError
+	if !errors.As(err, &pgErr) {
+		return utils.StorageError(err, utils.ErrUnknown, "unexpected error from postgres")
+	}
+	if pgerrcode.IsIntegrityConstraintViolation(pgErr.Code) {
+		// TODO: probably should specify which constraint
+		return utils.StorageError(err, utils.ErrConflict, pgErr.Message)
+	}
+	if pgerrcode.IsNoData(pgErr.Code) {
+		return utils.StorageError(err, utils.ErrNotFound, pgErr.Message)
+	}
+	return utils.StorageError(err, utils.ErrUnimplemented, "unimplemented error")
+}
diff --git a/internal/storage/solution.go b/internal/contests/repository/solution.go
similarity index 99%
rename from internal/storage/solution.go
rename to internal/contests/repository/solution.go
index 88c1822..cc46339 100644
--- a/internal/storage/solution.go
+++ b/internal/contests/repository/solution.go
@@ -1,4 +1,4 @@
-package storage
+package repository
 
 import (
 	"context"
diff --git a/internal/storage/task.go b/internal/contests/repository/task.go
similarity index 98%
rename from internal/storage/task.go
rename to internal/contests/repository/task.go
index 0e08fe4..82e2d85 100644
--- a/internal/storage/task.go
+++ b/internal/contests/repository/task.go
@@ -1,4 +1,4 @@
-package storage
+package repository
 
 import (
 	"context"
diff --git a/internal/contests/usecase.go b/internal/contests/usecase.go
new file mode 100644
index 0000000..e90643b
--- /dev/null
+++ b/internal/contests/usecase.go
@@ -0,0 +1,13 @@
+package contests
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+)
+
+type ContestUseCase interface {
+	CreateContest(ctx context.Context, contest *models.Contest) (int32, error)
+	ReadContestById(ctx context.Context, id int32) (*models.Contest, error)
+	UpdateContest(ctx context.Context, contest *models.Contest) error
+	DeleteContest(ctx context.Context, id int32) error
+}
diff --git a/opa/all.rego b/internal/contests/usecase/all.rego
similarity index 100%
rename from opa/all.rego
rename to internal/contests/usecase/all.rego
diff --git a/internal/services/participants.go b/internal/contests/usecase/participants.go
similarity index 99%
rename from internal/services/participants.go
rename to internal/contests/usecase/participants.go
index 72eaebd..13351ae 100644
--- a/internal/services/participants.go
+++ b/internal/contests/usecase/participants.go
@@ -1,4 +1,4 @@
-package services
+package usecase
 
 import (
 	"context"
diff --git a/internal/services/permission.go b/internal/contests/usecase/permission.go
similarity index 100%
rename from internal/services/permission.go
rename to internal/contests/usecase/permission.go
diff --git a/internal/services/solution.go b/internal/contests/usecase/solution.go
similarity index 99%
rename from internal/services/solution.go
rename to internal/contests/usecase/solution.go
index 6d61013..73335b1 100644
--- a/internal/services/solution.go
+++ b/internal/contests/usecase/solution.go
@@ -1,4 +1,4 @@
-package services
+package usecase
 
 import (
 	"context"
diff --git a/internal/services/task.go b/internal/contests/usecase/task.go
similarity index 81%
rename from internal/services/task.go
rename to internal/contests/usecase/task.go
index 401a22f..719fb44 100644
--- a/internal/services/task.go
+++ b/internal/contests/usecase/task.go
@@ -1,9 +1,9 @@
-package services
+package usecase
 
 import (
 	"context"
 	"git.sch9.ru/new_gate/models"
-	"git.sch9.ru/new_gate/ms-tester/internal/lib"
+	"git.sch9.ru/new_gate/ms-tester/pkg/utils"
 )
 
 type TaskStorage interface {
@@ -28,14 +28,14 @@ func NewTaskService(
 
 func (service *TaskService) CreateTask(ctx context.Context, task models.Task) (int32, error) {
 	if !service.permissionService.Allowed(ctx, extractUser(ctx), "create") {
-		return 0, lib.ServiceError(nil, lib.ErrNoPermission, "permission denied")
+		return 0, utils.ServiceError(nil, utils.ErrNoPermission, "permission denied")
 	}
 	return service.taskStorage.CreateTask(ctx, task)
 }
 
 func (service *TaskService) DeleteTask(ctx context.Context, id int32) error {
 	if !service.permissionService.Allowed(ctx, extractUser(ctx), "delete") {
-		return lib.ServiceError(nil, lib.ErrNoPermission, "permission denied")
+		return utils.ServiceError(nil, utils.ErrNoPermission, "permission denied")
 	}
 	return service.taskStorage.DeleteTask(ctx, id)
 }
diff --git a/internal/services/contest.go b/internal/contests/usecase/usecase.go
similarity index 79%
rename from internal/services/contest.go
rename to internal/contests/usecase/usecase.go
index c792fd8..8c9af4e 100644
--- a/internal/services/contest.go
+++ b/internal/contests/usecase/usecase.go
@@ -1,20 +1,13 @@
-package services
+package usecase
 
 import (
 	"context"
 	"git.sch9.ru/new_gate/models"
-	"git.sch9.ru/new_gate/ms-tester/internal/lib"
+	"git.sch9.ru/new_gate/ms-tester/internal/contests"
 )
 
-type ContestStorage interface {
-	CreateContest(ctx context.Context, contest *models.Contest) (int32, error)
-	ReadContestById(ctx context.Context, id int32) (*models.Contest, error)
-	UpdateContest(ctx context.Context, contest *models.Contest) error
-	DeleteContest(ctx context.Context, id int32) error
-}
-
 type ContestService struct {
-	contestStorage    ContestStorage
+	contestStorage    contests.ContestRepository
 	permissionService IPermissionService
 }
 
diff --git a/internal/languages/delivery.go b/internal/languages/delivery.go
new file mode 100644
index 0000000..e86683a
--- /dev/null
+++ b/internal/languages/delivery.go
@@ -0,0 +1,4 @@
+package languages
+
+type languageHandlers interface {
+}
diff --git a/internal/languages/delivery/grpc/handlers.go b/internal/languages/delivery/grpc/handlers.go
new file mode 100644
index 0000000..21e034e
--- /dev/null
+++ b/internal/languages/delivery/grpc/handlers.go
@@ -0,0 +1 @@
+package grpc
diff --git a/internal/languages/pg_repository.go b/internal/languages/pg_repository.go
new file mode 100644
index 0000000..b966134
--- /dev/null
+++ b/internal/languages/pg_repository.go
@@ -0,0 +1,10 @@
+package languages
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+)
+
+type LanguageRepository interface {
+	ReadLanguageById(ctx context.Context, id int32) (*models.Language, error)
+}
diff --git a/internal/languages/repository/pg_repository.go b/internal/languages/repository/pg_repository.go
new file mode 100644
index 0000000..add08ea
--- /dev/null
+++ b/internal/languages/repository/pg_repository.go
@@ -0,0 +1,28 @@
+package repository
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+	"git.sch9.ru/new_gate/ms-tester/pkg/utils"
+	"github.com/jmoiron/sqlx"
+	"go.uber.org/zap"
+)
+
+type LanguageRepository struct {
+	db     *sqlx.DB
+	logger *zap.Logger
+}
+
+func NewLanguageRepository(db *sqlx.DB, logger *zap.Logger) *LanguageRepository {
+	return &LanguageRepository{
+		db:     db,
+		logger: logger,
+	}
+}
+
+func (r *LanguageRepository) ReadLanguageById(ctx context.Context, id int32) (*models.Language, error) {
+	if id <= int32(len(models.Languages)) {
+		return nil, utils.StorageError(nil, utils.ErrNotFound, "languages not found")
+	}
+	return &models.Languages[id], nil
+}
diff --git a/internal/languages/usecase.go b/internal/languages/usecase.go
new file mode 100644
index 0000000..b6eab08
--- /dev/null
+++ b/internal/languages/usecase.go
@@ -0,0 +1,10 @@
+package languages
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+)
+
+type LanguageUseCase interface {
+	ReadLanguageById(ctx context.Context, id int32) (*models.Language, error)
+}
diff --git a/internal/languages/usecase/all.rego b/internal/languages/usecase/all.rego
new file mode 100644
index 0000000..8525c6a
--- /dev/null
+++ b/internal/languages/usecase/all.rego
@@ -0,0 +1,44 @@
+package problem.rbac
+
+import rego.v1
+
+spectator := 0
+participant := 1
+moderator := 2
+admin := 3
+
+permissions := {
+	"read": is_spectator,
+	"participate": is_participant,
+	"update": is_moderator,
+	"create": is_moderator,
+	"delete": is_moderator,
+}
+
+default allow := false
+
+allow if is_admin
+
+allow if {
+	permissions[input.action]
+}
+
+default is_admin := false
+is_admin if {
+	input.user.role == admin
+}
+
+default is_moderator := false
+is_moderator if {
+	input.user.role >= moderator
+}
+
+default is_participant := false
+is_participant if {
+	input.user.role >= participant
+}
+
+default is_spectator := true
+is_spectator if {
+	input.user.role >= spectator
+}
diff --git a/internal/languages/usecase/permission.go b/internal/languages/usecase/permission.go
new file mode 100644
index 0000000..59af1f8
--- /dev/null
+++ b/internal/languages/usecase/permission.go
@@ -0,0 +1,39 @@
+package services
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+	"github.com/open-policy-agent/opa/rego"
+)
+
+type PermissionService struct {
+	query *rego.PreparedEvalQuery
+}
+
+func NewPermissionService() *PermissionService {
+	query, err := rego.New(
+		rego.Query("allow = data.problem.rbac.allow"),
+		rego.Load([]string{"./opa/all.rego"}, nil),
+	).PrepareForEval(context.TODO())
+
+	if err != nil {
+		panic(err)
+	}
+
+	return &PermissionService{
+		query: &query,
+	}
+}
+
+func (s *PermissionService) Allowed(ctx context.Context, user *models.User, action string) bool {
+	input := map[string]interface{}{
+		"user":   user,
+		"action": action,
+	}
+
+	result, err := s.query.Eval(ctx, rego.EvalInput(input))
+	if err != nil {
+		panic(err)
+	}
+	return result[0].Bindings["allow"].(bool)
+}
diff --git a/internal/services/language.go b/internal/languages/usecase/usecase.go
similarity index 70%
rename from internal/services/language.go
rename to internal/languages/usecase/usecase.go
index 42db07f..9ce1f82 100644
--- a/internal/services/language.go
+++ b/internal/languages/usecase/usecase.go
@@ -1,16 +1,13 @@
-package services
+package usecase
 
 import (
 	"context"
 	"git.sch9.ru/new_gate/models"
+	"git.sch9.ru/new_gate/ms-tester/internal/languages"
 )
 
-type LanguageStorage interface {
-	ReadLanguageById(ctx context.Context, id int32) (*models.Language, error)
-}
-
-type LanguageService struct {
-	languageStorage LanguageStorage
+type LanguageUseCase struct {
+	languageRepo languages.LanguageRepository
 }
 
 func NewLanguageService(
diff --git a/internal/lib/lib.go b/internal/lib/lib.go
deleted file mode 100644
index 2cc988d..0000000
--- a/internal/lib/lib.go
+++ /dev/null
@@ -1,17 +0,0 @@
-package lib
-
-import (
-	"time"
-)
-
-func AsTimeP(t time.Time) *time.Time {
-	return &t
-}
-
-func AsInt32P(v int32) *int32 {
-	return &v
-}
-
-func AsStringP(str string) *string {
-	return &str
-}
diff --git a/internal/problems/delivery.go b/internal/problems/delivery.go
new file mode 100644
index 0000000..0e36f9e
--- /dev/null
+++ b/internal/problems/delivery.go
@@ -0,0 +1,13 @@
+package problems
+
+import (
+	"context"
+	problemv1 "git.sch9.ru/new_gate/ms-tester/pkg/go/gen/proto/problem/v1"
+	"google.golang.org/protobuf/types/known/emptypb"
+)
+
+type Handlers interface {
+	CreateProblem(server problemv1.ProblemService_CreateProblemServer) error
+	ReadProblem(ctx context.Context, req *problemv1.ReadProblemRequest) (*problemv1.ReadProblemResponse, error)
+	DeleteProblem(ctx context.Context, req *problemv1.DeleteProblemRequest) (*emptypb.Empty, error)
+}
diff --git a/internal/transport/problem.go b/internal/problems/delivery/grpc/handlers.go
similarity index 74%
rename from internal/transport/problem.go
rename to internal/problems/delivery/grpc/handlers.go
index ef5645d..d7e7bbe 100644
--- a/internal/transport/problem.go
+++ b/internal/problems/delivery/grpc/handlers.go
@@ -1,10 +1,12 @@
-package transport
+package grpc
 
 import (
 	"context"
 	"git.sch9.ru/new_gate/models"
 	"git.sch9.ru/new_gate/ms-tester/internal/lib"
+	"git.sch9.ru/new_gate/ms-tester/internal/problems"
 	problemv1 "git.sch9.ru/new_gate/ms-tester/pkg/go/gen/proto/problem/v1"
+	"git.sch9.ru/new_gate/ms-tester/pkg/utils"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/types/known/emptypb"
@@ -12,10 +14,16 @@ import (
 	"os"
 )
 
-func (s *TesterServer) CreateProblem(server problemv1.ProblemService_CreateProblemServer) error {
+type problemHandlers struct {
+	problemv1.UnimplementedProblemServiceServer
+
+	problemUC problems.ProblemUseCase
+}
+
+func (h *problemHandlers) CreateProblem(server problemv1.ProblemService_CreateProblemServer) error {
 	ctx := server.Context()
 
-	if err := s.problemService.CanCreateProblem(ctx); err != nil {
+	if err := h.problemUC.CanCreateProblem(ctx); err != nil {
 		return err
 	}
 
@@ -42,7 +50,7 @@ func (s *TesterServer) CreateProblem(server problemv1.ProblemService_CreateProbl
 		return err // FIXME
 	}
 
-	id, err := s.problemService.CreateProblem(ctx, p) // FIXME
+	id, err := h.problemUC.CreateProblem(ctx, p) // FIXME
 	if err != nil {
 		return err
 	}
@@ -113,8 +121,8 @@ func readChunks(ctx context.Context, server problemv1.ProblemService_CreateProbl
 	return ch
 }
 
-func (s *TesterServer) ReadProblem(ctx context.Context, req *problemv1.ReadProblemRequest) (*problemv1.ReadProblemResponse, error) {
-	problem, err := s.problemService.ReadProblemById(ctx, req.GetId())
+func (h *problemHandlers) ReadProblem(ctx context.Context, req *problemv1.ReadProblemRequest) (*problemv1.ReadProblemResponse, error) {
+	problem, err := h.problemUC.ReadProblemById(ctx, req.GetId())
 	if err != nil {
 		return nil, err
 	}
@@ -125,13 +133,13 @@ func (s *TesterServer) ReadProblem(ctx context.Context, req *problemv1.ReadProbl
 			Description: *problem.Description,
 			TimeLimit:   *problem.TimeLimit,
 			MemoryLimit: *problem.MemoryLimit,
-			CreatedAt:   AsTimestampP(problem.CreatedAt),
-			UpdatedAt:   AsTimestampP(problem.UpdatedAt),
+			CreatedAt:   utils.TimestampP(problem.CreatedAt),
+			UpdatedAt:   utils.TimestampP(problem.UpdatedAt),
 		},
 	}, nil
 }
 
-//func (s *TesterServer) UpdateProblem(ctx context.Context, req *problemv1.UpdateProblemRequest) (*emptypb.Empty, error) {
+//func (h *problemHandlers) UpdateProblem(ctx context.Context, req *problemv1.UpdateProblemRequest) (*emptypb.Empty, error) {
 //	problem := req.GetProblem()
 //	if problem == nil {
 //		return nil, status.Errorf(codes.Unknown, "") // FIXME
@@ -153,8 +161,8 @@ func (s *TesterServer) ReadProblem(ctx context.Context, req *problemv1.ReadProbl
 //	return &emptypb.Empty{}, nil
 //}
 
-func (s *TesterServer) DeleteProblem(ctx context.Context, req *problemv1.DeleteProblemRequest) (*emptypb.Empty, error) {
-	err := s.problemService.DeleteProblem(ctx, req.GetId())
+func (h *problemHandlers) DeleteProblem(ctx context.Context, req *problemv1.DeleteProblemRequest) (*emptypb.Empty, error) {
+	err := h.problemUC.DeleteProblem(ctx, req.GetId())
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/problems/pg_repository.go b/internal/problems/pg_repository.go
new file mode 100644
index 0000000..f4e1358
--- /dev/null
+++ b/internal/problems/pg_repository.go
@@ -0,0 +1,13 @@
+package problems
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+)
+
+type ProblemPostgresRepository interface {
+	CreateProblem(ctx context.Context, problem *models.Problem, testGroupData []models.TestGroupData) (int32, error)
+	ReadProblemById(ctx context.Context, id int32) (*models.Problem, error)
+	UpdateProblem(ctx context.Context, problem *models.Problem) error
+	DeleteProblem(ctx context.Context, id int32) error
+}
diff --git a/internal/storage/problem.go b/internal/problems/repository/pg_repository.go
similarity index 63%
rename from internal/storage/problem.go
rename to internal/problems/repository/pg_repository.go
index 4f7b52d..c68552b 100644
--- a/internal/storage/problem.go
+++ b/internal/problems/repository/pg_repository.go
@@ -1,26 +1,29 @@
-package storage
+package repository
 
 import (
 	"context"
 	"errors"
 	"git.sch9.ru/new_gate/models"
+	"git.sch9.ru/new_gate/ms-tester/pkg/utils"
+	"github.com/jackc/pgerrcode"
+	"github.com/jackc/pgx/v5/pgconn"
 	"github.com/jmoiron/sqlx"
 	"go.uber.org/zap"
 )
 
-type ProblemStorage struct {
+type ProblemRepository struct {
 	db     *sqlx.DB
 	logger *zap.Logger
 }
 
-func NewProblemStorage(db *sqlx.DB, logger *zap.Logger) *ProblemStorage {
-	return &ProblemStorage{
+func NewProblemRepository(db *sqlx.DB, logger *zap.Logger) *ProblemRepository {
+	return &ProblemRepository{
 		db:     db,
 		logger: logger,
 	}
 }
 
-func (storage *ProblemStorage) CreateProblem(ctx context.Context, problem *models.Problem, testGroupData []models.TestGroupData) (int32, error) {
+func (storage *ProblemRepository) CreateProblem(ctx context.Context, problem *models.Problem, testGroupData []models.TestGroupData) (int32, error) {
 	tx, err := storage.db.Beginx()
 	if err != nil {
 		return 0, handlePgErr(err)
@@ -80,7 +83,7 @@ RETURNING id
 	return id, nil
 }
 
-func (storage *ProblemStorage) ReadProblemById(ctx context.Context, id int32) (*models.Problem, error) {
+func (storage *ProblemRepository) ReadProblemById(ctx context.Context, id int32) (*models.Problem, error) {
 	var problem models.Problem
 	query := storage.db.Rebind("SELECT * from problems WHERE id=? LIMIT 1")
 	err := storage.db.GetContext(ctx, &problem, query, id)
@@ -90,7 +93,7 @@ func (storage *ProblemStorage) ReadProblemById(ctx context.Context, id int32) (*
 	return &problem, nil
 }
 
-func (storage *ProblemStorage) UpdateProblem(ctx context.Context, problem *models.Problem) error {
+func (storage *ProblemRepository) UpdateProblem(ctx context.Context, problem *models.Problem) error {
 	query := storage.db.Rebind("UPDATE problems SET name=?,description=?,time_limit=?,memory_limit=? WHERE id=?")
 	_, err := storage.db.ExecContext(ctx, query, problem.Name, problem.Description, problem.TimeLimit, problem.MemoryLimit, problem.Id)
 	if err != nil {
@@ -99,7 +102,7 @@ func (storage *ProblemStorage) UpdateProblem(ctx context.Context, problem *model
 	return nil
 }
 
-func (storage *ProblemStorage) DeleteProblem(ctx context.Context, id int32) error {
+func (storage *ProblemRepository) DeleteProblem(ctx context.Context, id int32) error {
 	query := storage.db.Rebind("DELETE FROM problems WHERE id=?")
 	_, err := storage.db.ExecContext(ctx, query, id)
 	if err != nil {
@@ -108,3 +111,18 @@ func (storage *ProblemStorage) DeleteProblem(ctx context.Context, id int32) erro
 
 	return nil
 }
+
+func handlePgErr(err error) error {
+	var pgErr *pgconn.PgError
+	if !errors.As(err, &pgErr) {
+		return utils.StorageError(err, utils.ErrUnknown, "unexpected error from postgres")
+	}
+	if pgerrcode.IsIntegrityConstraintViolation(pgErr.Code) {
+		// TODO: probably should specify which constraint
+		return utils.StorageError(err, utils.ErrConflict, pgErr.Message)
+	}
+	if pgerrcode.IsNoData(pgErr.Code) {
+		return utils.StorageError(err, utils.ErrNotFound, pgErr.Message)
+	}
+	return utils.StorageError(err, utils.ErrUnimplemented, "unimplemented error")
+}
diff --git a/internal/problems/usecase.go b/internal/problems/usecase.go
new file mode 100644
index 0000000..162f23b
--- /dev/null
+++ b/internal/problems/usecase.go
@@ -0,0 +1,17 @@
+package problems
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+)
+
+type ProblemUseCase interface {
+	CanCreateProblem(ctx context.Context) error
+	CanReadProblemById(ctx context.Context) error
+	CanUpdateProblem(ctx context.Context) error
+	CanDeleteProblem(ctx context.Context) error
+	CreateProblem(ctx context.Context, problem *models.Problem) (int32, error)
+	ReadProblemById(ctx context.Context, id int32) (*models.Problem, error)
+	UpdateProblem(ctx context.Context, problem *models.Problem) error
+	DeleteProblem(ctx context.Context, id int32) error
+}
diff --git a/internal/problems/usecase/all.rego b/internal/problems/usecase/all.rego
new file mode 100644
index 0000000..8525c6a
--- /dev/null
+++ b/internal/problems/usecase/all.rego
@@ -0,0 +1,44 @@
+package problem.rbac
+
+import rego.v1
+
+spectator := 0
+participant := 1
+moderator := 2
+admin := 3
+
+permissions := {
+	"read": is_spectator,
+	"participate": is_participant,
+	"update": is_moderator,
+	"create": is_moderator,
+	"delete": is_moderator,
+}
+
+default allow := false
+
+allow if is_admin
+
+allow if {
+	permissions[input.action]
+}
+
+default is_admin := false
+is_admin if {
+	input.user.role == admin
+}
+
+default is_moderator := false
+is_moderator if {
+	input.user.role >= moderator
+}
+
+default is_participant := false
+is_participant if {
+	input.user.role >= participant
+}
+
+default is_spectator := true
+is_spectator if {
+	input.user.role >= spectator
+}
diff --git a/internal/problems/usecase/permission.go b/internal/problems/usecase/permission.go
new file mode 100644
index 0000000..59af1f8
--- /dev/null
+++ b/internal/problems/usecase/permission.go
@@ -0,0 +1,39 @@
+package services
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+	"github.com/open-policy-agent/opa/rego"
+)
+
+type PermissionService struct {
+	query *rego.PreparedEvalQuery
+}
+
+func NewPermissionService() *PermissionService {
+	query, err := rego.New(
+		rego.Query("allow = data.problem.rbac.allow"),
+		rego.Load([]string{"./opa/all.rego"}, nil),
+	).PrepareForEval(context.TODO())
+
+	if err != nil {
+		panic(err)
+	}
+
+	return &PermissionService{
+		query: &query,
+	}
+}
+
+func (s *PermissionService) Allowed(ctx context.Context, user *models.User, action string) bool {
+	input := map[string]interface{}{
+		"user":   user,
+		"action": action,
+	}
+
+	result, err := s.query.Eval(ctx, rego.EvalInput(input))
+	if err != nil {
+		panic(err)
+	}
+	return result[0].Bindings["allow"].(bool)
+}
diff --git a/internal/services/problem.go b/internal/problems/usecase/usecase.go
similarity index 75%
rename from internal/services/problem.go
rename to internal/problems/usecase/usecase.go
index e65a9d5..b46a988 100644
--- a/internal/services/problem.go
+++ b/internal/problems/usecase/usecase.go
@@ -1,9 +1,10 @@
-package services
+package usecase
 
 import (
 	"context"
 	"git.sch9.ru/new_gate/models"
 	"git.sch9.ru/new_gate/ms-tester/internal/lib"
+	"git.sch9.ru/new_gate/ms-tester/pkg/external/pandoc"
 )
 
 type ProblemStorage interface {
@@ -13,26 +14,22 @@ type ProblemStorage interface {
 	DeleteProblem(ctx context.Context, id int32) error
 }
 
-type PandocClient interface {
-	ConvertLatexToHtml5(ctx context.Context, text string) (string, error)
-}
-
 type IPermissionService interface {
 	Allowed(ctx context.Context, user *models.User, action string) bool
 }
 
-type ProblemService struct {
+type ProblemUseCase struct {
 	problemStorage    ProblemStorage
-	pandocClient      PandocClient
+	pandocClient      pandoc.PandocClient
 	permissionService IPermissionService
 }
 
-func NewProblemService(
+func NewProblemUseCase(
 	problemStorage ProblemStorage,
-	pandocClient PandocClient,
+	pandocClient pandoc.PandocClient,
 	permissionService IPermissionService,
-) *ProblemService {
-	return &ProblemService{
+) *ProblemUseCase {
+	return &ProblemUseCase{
 		problemStorage:    problemStorage,
 		pandocClient:      pandocClient,
 		permissionService: permissionService,
@@ -43,35 +40,35 @@ func extractUser(ctx context.Context) *models.User {
 	return ctx.Value("user").(*models.User)
 }
 
-func (service *ProblemService) CanCreateProblem(ctx context.Context) error {
+func (service *ProblemUseCase) CanCreateProblem(ctx context.Context) error {
 	if !service.permissionService.Allowed(ctx, extractUser(ctx), "create") {
 		return lib.ServiceError(nil, lib.ErrNoPermission, "permission denied")
 	}
 	return nil
 }
 
-func (service *ProblemService) CanReadProblemById(ctx context.Context) error {
+func (service *ProblemUseCase) CanReadProblemById(ctx context.Context) error {
 	if !service.permissionService.Allowed(ctx, extractUser(ctx), "read") {
 		return lib.ServiceError(nil, lib.ErrNoPermission, "permission denied")
 	}
 	return nil
 }
 
-func (service *ProblemService) CanUpdateProblem(ctx context.Context) error {
+func (service *ProblemUseCase) CanUpdateProblem(ctx context.Context) error {
 	if !service.permissionService.Allowed(ctx, extractUser(ctx), "update") {
 		return lib.ServiceError(nil, lib.ErrNoPermission, "permission denied")
 	}
 	return nil
 }
 
-func (service *ProblemService) CanDeleteProblem(ctx context.Context) error {
+func (service *ProblemUseCase) CanDeleteProblem(ctx context.Context) error {
 	if !service.permissionService.Allowed(ctx, extractUser(ctx), "delete") {
 		return lib.ServiceError(nil, lib.ErrNoPermission, "permission denied")
 	}
 	return nil
 }
 
-func (service *ProblemService) CreateProblem(ctx context.Context, problem *models.Problem) (int32, error) {
+func (service *ProblemUseCase) CreateProblem(ctx context.Context, problem *models.Problem) (int32, error) {
 	if err := service.CanCreateProblem(ctx); err != nil {
 		return 0, err
 	}
@@ -82,21 +79,21 @@ func (service *ProblemService) CreateProblem(ctx context.Context, problem *model
 	return service.problemStorage.CreateProblem(ctx, problem, nil)
 }
 
-func (service *ProblemService) ReadProblemById(ctx context.Context, id int32) (*models.Problem, error) {
+func (service *ProblemUseCase) ReadProblemById(ctx context.Context, id int32) (*models.Problem, error) {
 	if err := service.CanReadProblemById(ctx); err != nil {
 		return nil, err
 	}
 	return service.problemStorage.ReadProblemById(ctx, id)
 }
 
-func (service *ProblemService) UpdateProblem(ctx context.Context, problem *models.Problem) error {
+func (service *ProblemUseCase) UpdateProblem(ctx context.Context, problem *models.Problem) error {
 	if err := service.CanUpdateProblem(ctx); err != nil {
 		return err
 	}
 	return service.problemStorage.UpdateProblem(ctx, problem)
 }
 
-func (service *ProblemService) DeleteProblem(ctx context.Context, id int32) error {
+func (service *ProblemUseCase) DeleteProblem(ctx context.Context, id int32) error {
 	if err := service.CanDeleteProblem(ctx); err != nil {
 		return err
 	}
diff --git a/internal/services/user.go b/internal/services/user.go
deleted file mode 100644
index ecdec84..0000000
--- a/internal/services/user.go
+++ /dev/null
@@ -1,29 +0,0 @@
-package services
-
-import (
-	"context"
-	"git.sch9.ru/new_gate/models"
-)
-
-type UserStorage interface {
-	CreateUser(ctx context.Context, user *models.User) error
-	ReadUserById(ctx context.Context, userId int32) (*models.User, error)
-}
-
-type UserService struct {
-	userStorage UserStorage
-}
-
-func NewUserService(userStorage UserStorage) *UserService {
-	return &UserService{
-		userStorage: userStorage,
-	}
-}
-
-func (s *UserService) CreateUser(ctx context.Context, user *models.User) error {
-	return s.userStorage.CreateUser(ctx, user)
-}
-
-func (s *UserService) ReadUserById(ctx context.Context, userId int32) (*models.User, error) {
-	return s.userStorage.ReadUserById(ctx, userId)
-}
diff --git a/internal/storage/contests.go b/internal/storage/contests.go
deleted file mode 100644
index 146bcd6..0000000
--- a/internal/storage/contests.go
+++ /dev/null
@@ -1,78 +0,0 @@
-package storage
-
-import (
-	"context"
-	"git.sch9.ru/new_gate/models"
-	"github.com/jmoiron/sqlx"
-	"go.uber.org/zap"
-)
-
-type ContestStorage struct {
-	db     *sqlx.DB
-	logger *zap.Logger
-}
-
-func NewContestStorage(db *sqlx.DB, logger *zap.Logger) *ContestStorage {
-	return &ContestStorage{
-		db:     db,
-		logger: logger,
-	}
-}
-
-func (storage *ContestStorage) CreateContest(ctx context.Context, contest *models.Contest) (int32, error) {
-	query := storage.db.Rebind(`
-INSERT INTO contests
-    (name)
-VALUES (?)
-RETURNING id
-`)
-
-	rows, err := storage.db.QueryxContext(
-		ctx,
-		query,
-		contest.Name,
-	)
-	if err != nil {
-		return 0, handlePgErr(err)
-	}
-
-	defer rows.Close()
-	var id int32
-	err = rows.StructScan(&id)
-	if err != nil {
-		return 0, handlePgErr(err)
-	}
-
-	return id, nil
-
-}
-
-func (storage *ContestStorage) ReadContestById(ctx context.Context, id int32) (*models.Contest, error) {
-	var contest models.Contest
-	query := storage.db.Rebind("SELECT * from contests WHERE id=? LIMIT 1")
-	err := storage.db.GetContext(ctx, &contest, query, id)
-	if err != nil {
-		return nil, handlePgErr(err)
-	}
-	return &contest, nil
-}
-
-func (storage *ContestStorage) UpdateContest(ctx context.Context, contest *models.Contest) error {
-	query := storage.db.Rebind("UPDATE contests SET name=? WHERE id=?")
-	_, err := storage.db.ExecContext(ctx, query, contest.Name, contest.Id)
-	if err != nil {
-		return handlePgErr(err)
-	}
-
-	return nil
-}
-
-func (storage *ContestStorage) DeleteContest(ctx context.Context, id int32) error {
-	query := storage.db.Rebind("DELETE FROM contests WHERE id=?")
-	_, err := storage.db.ExecContext(ctx, query, id)
-	if err != nil {
-		return handlePgErr(err)
-	}
-
-	return nil
-}
diff --git a/internal/storage/errhandling.go b/internal/storage/errhandling.go
deleted file mode 100644
index ff720e3..0000000
--- a/internal/storage/errhandling.go
+++ /dev/null
@@ -1,23 +0,0 @@
-package storage
-
-import (
-	"errors"
-	"git.sch9.ru/new_gate/ms-tester/internal/lib"
-	"github.com/jackc/pgerrcode"
-	"github.com/jackc/pgx/v5/pgconn"
-)
-
-func handlePgErr(err error) error {
-	var pgErr *pgconn.PgError
-	if !errors.As(err, &pgErr) {
-		return lib.StorageError(err, lib.ErrUnknown, "unexpected error from postgres")
-	}
-	if pgerrcode.IsIntegrityConstraintViolation(pgErr.Code) {
-		// TODO: probably should specify which constraint
-		return lib.StorageError(err, lib.ErrConflict, pgErr.Message)
-	}
-	if pgerrcode.IsNoData(pgErr.Code) {
-		return lib.StorageError(err, lib.ErrNotFound, pgErr.Message)
-	}
-	return lib.StorageError(err, lib.ErrUnimplemented, "unimplemented error")
-}
diff --git a/internal/storage/language.go b/internal/storage/language.go
deleted file mode 100644
index b8be4e2..0000000
--- a/internal/storage/language.go
+++ /dev/null
@@ -1,28 +0,0 @@
-package storage
-
-import (
-	"context"
-	"git.sch9.ru/new_gate/models"
-	"git.sch9.ru/new_gate/ms-tester/internal/lib"
-	"github.com/jmoiron/sqlx"
-	"go.uber.org/zap"
-)
-
-type LanguageStorage struct {
-	db     *sqlx.DB
-	logger *zap.Logger
-}
-
-func NewLanguageStorage(db *sqlx.DB, logger *zap.Logger) *LanguageStorage {
-	return &LanguageStorage{
-		db:     db,
-		logger: logger,
-	}
-}
-
-func (storage *LanguageStorage) ReadLanguageById(ctx context.Context, id int32) (*models.Language, error) {
-	if id <= int32(len(models.Languages)) {
-		return nil, lib.StorageError(nil, lib.ErrNotFound, "language not found")
-	}
-	return &models.Languages[id], nil
-}
diff --git a/internal/storage/user.go b/internal/storage/user.go
deleted file mode 100644
index 64a0172..0000000
--- a/internal/storage/user.go
+++ /dev/null
@@ -1,42 +0,0 @@
-package storage
-
-import (
-	"context"
-	"git.sch9.ru/new_gate/models"
-	"github.com/jmoiron/sqlx"
-)
-
-type UserStorage struct {
-	db *sqlx.DB
-}
-
-func NewUserStorage(db *sqlx.DB) *UserStorage {
-	return &UserStorage{
-		db: db,
-	}
-}
-
-func (storage *UserStorage) CreateUser(ctx context.Context, user *models.User) error {
-	query := storage.db.Rebind("INSERT INTO users (user_id, role) VALUES (?, ?)")
-	_, err := storage.db.ExecContext(ctx, query, user.UserId, user.Role)
-	if err != nil {
-		return err
-	}
-	return nil
-}
-
-func (storage *UserStorage) ReadUserById(ctx context.Context, userId int32) (*models.User, error) {
-	query := storage.db.Rebind(`
-SELECT *
-FROM users
-WHERE user_id = ?
-LIMIT 1;
-`)
-
-	var user models.User
-	err := storage.db.GetContext(ctx, &user, query, userId)
-	if err != nil {
-		return nil, err
-	}
-	return &user, nil
-}
diff --git a/internal/tester/delivery.go b/internal/tester/delivery.go
new file mode 100644
index 0000000..3fdd542
--- /dev/null
+++ b/internal/tester/delivery.go
@@ -0,0 +1 @@
+package tester
diff --git a/internal/tester/delivery/grpc/handlers.go b/internal/tester/delivery/grpc/handlers.go
new file mode 100644
index 0000000..21e034e
--- /dev/null
+++ b/internal/tester/delivery/grpc/handlers.go
@@ -0,0 +1 @@
+package grpc
diff --git a/internal/tester/pg_repository.go b/internal/tester/pg_repository.go
new file mode 100644
index 0000000..3fdd542
--- /dev/null
+++ b/internal/tester/pg_repository.go
@@ -0,0 +1 @@
+package tester
diff --git a/internal/tester/repository/pg_repository.go b/internal/tester/repository/pg_repository.go
new file mode 100644
index 0000000..50a4378
--- /dev/null
+++ b/internal/tester/repository/pg_repository.go
@@ -0,0 +1 @@
+package repository
diff --git a/internal/tester/usecase.go b/internal/tester/usecase.go
new file mode 100644
index 0000000..3fdd542
--- /dev/null
+++ b/internal/tester/usecase.go
@@ -0,0 +1 @@
+package tester
diff --git a/internal/tester/usecase/all.rego b/internal/tester/usecase/all.rego
new file mode 100644
index 0000000..8525c6a
--- /dev/null
+++ b/internal/tester/usecase/all.rego
@@ -0,0 +1,44 @@
+package problem.rbac
+
+import rego.v1
+
+spectator := 0
+participant := 1
+moderator := 2
+admin := 3
+
+permissions := {
+	"read": is_spectator,
+	"participate": is_participant,
+	"update": is_moderator,
+	"create": is_moderator,
+	"delete": is_moderator,
+}
+
+default allow := false
+
+allow if is_admin
+
+allow if {
+	permissions[input.action]
+}
+
+default is_admin := false
+is_admin if {
+	input.user.role == admin
+}
+
+default is_moderator := false
+is_moderator if {
+	input.user.role >= moderator
+}
+
+default is_participant := false
+is_participant if {
+	input.user.role >= participant
+}
+
+default is_spectator := true
+is_spectator if {
+	input.user.role >= spectator
+}
diff --git a/internal/tester/usecase/permission.go b/internal/tester/usecase/permission.go
new file mode 100644
index 0000000..59af1f8
--- /dev/null
+++ b/internal/tester/usecase/permission.go
@@ -0,0 +1,39 @@
+package services
+
+import (
+	"context"
+	"git.sch9.ru/new_gate/models"
+	"github.com/open-policy-agent/opa/rego"
+)
+
+type PermissionService struct {
+	query *rego.PreparedEvalQuery
+}
+
+func NewPermissionService() *PermissionService {
+	query, err := rego.New(
+		rego.Query("allow = data.problem.rbac.allow"),
+		rego.Load([]string{"./opa/all.rego"}, nil),
+	).PrepareForEval(context.TODO())
+
+	if err != nil {
+		panic(err)
+	}
+
+	return &PermissionService{
+		query: &query,
+	}
+}
+
+func (s *PermissionService) Allowed(ctx context.Context, user *models.User, action string) bool {
+	input := map[string]interface{}{
+		"user":   user,
+		"action": action,
+	}
+
+	result, err := s.query.Eval(ctx, rego.EvalInput(input))
+	if err != nil {
+		panic(err)
+	}
+	return result[0].Bindings["allow"].(bool)
+}
diff --git a/internal/tester/usecase/usecase.go b/internal/tester/usecase/usecase.go
new file mode 100644
index 0000000..aed2454
--- /dev/null
+++ b/internal/tester/usecase/usecase.go
@@ -0,0 +1 @@
+package usecase
diff --git a/main.go b/main.go
index cfec229..40012c1 100644
--- a/main.go
+++ b/main.go
@@ -2,10 +2,11 @@ package main
 
 import (
 	"fmt"
-	"git.sch9.ru/new_gate/ms-tester/internal/lib"
+	"git.sch9.ru/new_gate/ms-tester/config"
 	"git.sch9.ru/new_gate/ms-tester/internal/services"
 	"git.sch9.ru/new_gate/ms-tester/internal/storage"
 	"git.sch9.ru/new_gate/ms-tester/internal/transport"
+	"git.sch9.ru/new_gate/ms-tester/pkg/external/pandoc"
 	sessionv1 "git.sch9.ru/new_gate/ms-tester/pkg/go/gen/proto/session/v1"
 	"github.com/ilyakaznacheev/cleanenv"
 	_ "github.com/jackc/pgx/v5/stdlib"
@@ -21,7 +22,7 @@ import (
 )
 
 func main() {
-	var cfg lib.Config
+	var cfg config.Config
 	err := cleanenv.ReadConfig(".env", &cfg)
 	if err != nil {
 		panic(fmt.Sprintf("error reading config: %s", err.Error()))
@@ -45,7 +46,7 @@ func main() {
 	//contestStorage := storage.NewContestStorage(db, logger)
 	//contestService := services.NewContestService(contestStorage)
 
-	pandocClient := lib.NewPandocClient(&http.Client{}, cfg.Pandoc)
+	pandocClient := pandoc.NewPandocClient(&http.Client{}, cfg.Pandoc)
 
 	grpcSessionClient, err := grpc.NewClient(cfg.Auth, grpc.WithTransportCredentials(insecure.NewCredentials()))
 	if err != nil {
diff --git a/migrations/20240727123308_initial.sql b/migrations/20240727123308_initial.sql
index 43ce8a3..5d534d8 100644
--- a/migrations/20240727123308_initial.sql
+++ b/migrations/20240727123308_initial.sql
@@ -211,21 +211,6 @@ CREATE TABLE IF NOT EXISTS participant_task
 );
 
 
-
-
-CREATE TABLE IF NOT EXISTS users
-(
-    user_id    INT         NOT NULL,
-    role       INT         NOT NULL,
-    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
-
-    CHECK ( role BETWEEN 0 AND 3),
-    PRIMARY KEY (user_id)
-);
-
-
-
-
 CREATE FUNCTION on_new_participant() RETURNS TRIGGER AS 
 $$ BEGIN
     --RAISE NOTICE 'NEW.ID:%, NEW.contest_id:%', NEW.id,NEW.contest_id;
@@ -288,7 +273,6 @@ $$;
 --CREATE TRIGGER languages_upd_trg BEFORE UPDATE ON languages FOR EACH ROW EXECUTE FUNCTION updated_at_update();
 CREATE TRIGGER problems_upd_trg BEFORE UPDATE ON problems FOR EACH ROW EXECUTE FUNCTION updated_at_update();
 CREATE TRIGGER contests_upd_trg BEFORE UPDATE ON contests FOR EACH ROW EXECUTE FUNCTION updated_at_update();
-CREATE TRIGGER users_upd_trg BEFORE UPDATE ON users FOR EACH ROW EXECUTE FUNCTION updated_at_update();
 -- +goose StatementEnd
 
 -- +goose Down
@@ -312,5 +296,4 @@ DROP TABLE IF EXISTS subtasks CASCADE;
 DROP TABLE IF EXISTS participants CASCADE;
 DROP TABLE IF EXISTS participant_task CASCADE;
 DROP TABLE IF EXISTS participant_subtask CASCADE;
-DROP TABLE IF EXISTS users CASCADE;
 -- +goose StatementEnd
diff --git a/pkg/external/aws/aws.go b/pkg/external/aws/aws.go
new file mode 100644
index 0000000..a1f9c0e
--- /dev/null
+++ b/pkg/external/aws/aws.go
@@ -0,0 +1 @@
+package aws
diff --git a/pkg/external/kafka/kafka.go b/pkg/external/kafka/kafka.go
new file mode 100644
index 0000000..82b3441
--- /dev/null
+++ b/pkg/external/kafka/kafka.go
@@ -0,0 +1 @@
+package kafka
diff --git a/pkg/external/ms-auth/client.go b/pkg/external/ms-auth/client.go
new file mode 100644
index 0000000..a8d771d
--- /dev/null
+++ b/pkg/external/ms-auth/client.go
@@ -0,0 +1 @@
+package ms_auth
diff --git a/internal/lib/pandoc.go b/pkg/external/pandoc/pandoc.go
similarity index 68%
rename from internal/lib/pandoc.go
rename to pkg/external/pandoc/pandoc.go
index 42701b0..af2427a 100644
--- a/internal/lib/pandoc.go
+++ b/pkg/external/pandoc/pandoc.go
@@ -1,4 +1,4 @@
-package lib
+package pandoc
 
 import (
 	"bytes"
@@ -8,13 +8,17 @@ import (
 	"net/http"
 )
 
-type PandocClient struct {
+type Client struct {
 	client  *http.Client
 	address string
 }
 
-func NewPandocClient(client *http.Client, address string) *PandocClient {
-	return &PandocClient{
+type PandocClient interface {
+	ConvertLatexToHtml5(ctx context.Context, text string) (string, error)
+}
+
+func NewPandocClient(client *http.Client, address string) *Client {
+	return &Client{
 		client:  client,
 		address: address,
 	}
@@ -26,7 +30,7 @@ type convertRequest struct {
 	To   string `json:"to"`
 }
 
-func (client *PandocClient) convert(ctx context.Context, text, from, to string) (string, error) {
+func (client *Client) convert(ctx context.Context, text, from, to string) (string, error) {
 	body, err := json.Marshal(convertRequest{
 		Text: text,
 		From: from,
@@ -62,6 +66,6 @@ func (client *PandocClient) convert(ctx context.Context, text, from, to string)
 	return string(body), nil
 }
 
-func (client *PandocClient) ConvertLatexToHtml5(ctx context.Context, text string) (string, error) {
+func (client *Client) ConvertLatexToHtml5(ctx context.Context, text string) (string, error) {
 	return client.convert(ctx, text, "latex", "html5")
 }
diff --git a/pkg/external/postgres/postgres.go b/pkg/external/postgres/postgres.go
new file mode 100644
index 0000000..b83463e
--- /dev/null
+++ b/pkg/external/postgres/postgres.go
@@ -0,0 +1,30 @@
+package postgres
+
+import (
+	"github.com/jmoiron/sqlx"
+	"time"
+)
+
+const (
+	maxOpenConns    = 60
+	connMaxLifetime = 120
+	maxIdleConns    = 30
+	connMaxIdleTime = 20
+)
+
+func NewPostgresDB(dsn string) (*sqlx.DB, error) {
+	db, err := sqlx.Open("pgx", dsn)
+	if err != nil {
+		return nil, err
+	}
+
+	db.SetMaxOpenConns(maxOpenConns)
+	db.SetConnMaxLifetime(connMaxLifetime * time.Second)
+	db.SetMaxIdleConns(maxIdleConns)
+	db.SetConnMaxIdleTime(connMaxIdleTime * time.Second)
+	if err = db.Ping(); err != nil {
+		return nil, err
+	}
+
+	return db, nil
+}
diff --git a/pkg/external/valkey/valkey.go b/pkg/external/valkey/valkey.go
new file mode 100644
index 0000000..c5a4900
--- /dev/null
+++ b/pkg/external/valkey/valkey.go
@@ -0,0 +1,12 @@
+package valkey
+
+import "github.com/valkey-io/valkey-go"
+
+func NewValkeyClient(dsn string) (valkey.Client, error) {
+	opts, err := valkey.ParseURL(dsn)
+	if err != nil {
+		return nil, err
+	}
+
+	return valkey.NewClient(opts)
+}
diff --git a/internal/lib/errors.go b/pkg/utils/errors.go
similarity index 99%
rename from internal/lib/errors.go
rename to pkg/utils/errors.go
index 888d17d..98bd286 100644
--- a/internal/lib/errors.go
+++ b/pkg/utils/errors.go
@@ -1,4 +1,4 @@
-package lib
+package utils
 
 import (
 	"errors"
diff --git a/pkg/utils/utils.go b/pkg/utils/utils.go
new file mode 100644
index 0000000..8492339
--- /dev/null
+++ b/pkg/utils/utils.go
@@ -0,0 +1,33 @@
+package utils
+
+import (
+	"google.golang.org/protobuf/types/known/timestamppb"
+	"time"
+)
+
+func AsTimeP(t time.Time) *time.Time {
+	return &t
+}
+
+func AsInt32P(v int32) *int32 {
+	return &v
+}
+
+func AsStringP(str string) *string {
+	return &str
+}
+
+func TimeP(t *timestamppb.Timestamp) *time.Time {
+	if t == nil {
+		return nil
+	}
+	tt := t.AsTime()
+	return &tt
+}
+
+func TimestampP(t *time.Time) *timestamppb.Timestamp {
+	if t == nil {
+		return nil
+	}
+	return timestamppb.New(*t)
+}