diff --git a/services/data_service/internal/manager/api.go b/services/data_service/internal/manager/api.go
new file mode 100644
index 0000000..8995f04
--- /dev/null
+++ b/services/data_service/internal/manager/api.go
@@ -0,0 +1,22 @@
+package manager
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/domain"
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/provider"
+)
+
+type SessionController interface {
+	NewSession(idleAfter time.Duration) uuid.UUID
+	AttachClient(id uuid.UUID, inBuf, outBuf int) (chan<- domain.Message, <-chan domain.Message, error)
+	DetachClient(id uuid.UUID) error
+	ConfigureSession(id uuid.UUID, next []domain.Identifier) error
+	CloseSession(id uuid.UUID) error
+}
+
+type ProviderController interface {
+	AddProvider(name string, p provider.Provider) error
+	RemoveProvider(name string) error
+}
diff --git a/services/data_service/internal/manager/manager.go b/services/data_service/internal/manager/manager.go
index ff6192a..dbd490a 100644
--- a/services/data_service/internal/manager/manager.go
+++ b/services/data_service/internal/manager/manager.go
@@ -47,7 +47,7 @@ func NewManager(r *router.Router) *Manager {
 	return m
 }
 
-// Public API (posts commands to loop)
+// API
 
 // AddProvider adds and starts a new provider.
 func (m *Manager) AddProvider(name string, p provider.Provider) error {
diff --git a/services/data_service/internal/worker/stateful.go b/services/data_service/internal/worker/stateful.go
deleted file mode 100644
index 4df0094..0000000
--- a/services/data_service/internal/worker/stateful.go
+++ /dev/null
@@ -1 +0,0 @@
-package worker
diff --git a/services/data_service/internal/worker/stateless.go b/services/data_service/internal/worker/stateless.go
deleted file mode 100644
index 4df0094..0000000
--- a/services/data_service/internal/worker/stateless.go
+++ /dev/null
@@ -1 +0,0 @@
-package worker
diff --git a/services/data_service/internal/worker/worker.go b/services/data_service/internal/worker/worker.go
new file mode 100644
index 0000000..f52cdd8
--- /dev/null
+++ b/services/data_service/internal/worker/worker.go
@@ -0,0 +1,12 @@
+package worker
+
+import (
+	"github.com/google/uuid"
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/manager"
+)
+
+type Worker interface {
+	ID() uuid.UUID
+	Start(cfg map[string]string, controller manager.SessionController) error
+	Stop()
+}