diff --git a/go.mod b/go.mod
index f803688..a7ae7e1 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,6 @@ module gitlab.michelsen.id/phillmichelsen/tessera
 go 1.25.1
 
 require (
-	github.com/coder/websocket v1.8.14
 	github.com/google/uuid v1.6.0
 	github.com/lmittmann/tint v1.1.2
 	google.golang.org/grpc v1.75.0
@@ -11,8 +10,10 @@ require (
 )
 
 require (
+	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
 	golang.org/x/net v0.43.0 // indirect
 	golang.org/x/sys v0.35.0 // indirect
 	golang.org/x/text v0.28.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250826171959-ef028d996bc1 // indirect
+	lukechampine.com/blake3 v1.4.1 // indirect
 )
diff --git a/go.sum b/go.sum
index 9d0e5c6..f35afde 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,3 @@
-github.com/coder/websocket v1.8.14 h1:9L0p0iKiNOibykf283eHkKUHHrpG7f65OE3BhhO7v9g=
-github.com/coder/websocket v1.8.14/go.mod h1:NX3SzP+inril6yawo5CQXx8+fk145lPDC6pumgx0mVg=
 github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
 github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
@@ -10,6 +8,8 @@ github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/klauspost/cpuid/v2 v2.0.9 h1:lgaqFMSdTdQYdZ04uHyN2d/eKdOMyi2YLSvlQIBFYa4=
+github.com/klauspost/cpuid/v2 v2.0.9/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
 github.com/lmittmann/tint v1.1.2 h1:2CQzrL6rslrsyjqLDwD11bZ5OpLBPU+g3G/r5LSfS8w=
 github.com/lmittmann/tint v1.1.2/go.mod h1:HIS3gSy7qNwGCj+5oRjAutErFBl4BzdQP6cJZ0NfMwE=
 go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=
@@ -38,3 +38,5 @@ google.golang.org/grpc v1.75.0 h1:+TW+dqTd2Biwe6KKfhE5JpiYIBWq865PhKGSXiivqt4=
 google.golang.org/grpc v1.75.0/go.mod h1:JtPAzKiq4v1xcAB2hydNlWI2RnF85XXcV0mhKXr2ecQ=
 google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
 google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
+lukechampine.com/blake3 v1.4.1 h1:I3Smz7gso8w4/TunLKec6K2fn+kyKtDxr/xcQEN84Wg=
+lukechampine.com/blake3 v1.4.1/go.mod h1:QFosUxmjB8mnrWFSNwKmvxHpfY72bmD2tQ0kBMM3kwo=
diff --git a/services/data_service/cmd/data_service/main.go b/services/data_service/cmd/data_service/main.go
index 49e8254..beb57ad 100644
--- a/services/data_service/cmd/data_service/main.go
+++ b/services/data_service/cmd/data_service/main.go
@@ -6,9 +6,6 @@ import (
 	"time"
 
 	"github.com/lmittmann/tint"
-	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/manager"
-	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/router"
-	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/worker"
 )
 
 func initLogger() *slog.Logger {
@@ -49,10 +46,5 @@ func main() {
 	slog.SetDefault(initLogger())
 	slog.Info("starting", "svc", "data-service")
 
-	// Setup
-	wr := worker.NewRegistry()
-	r, _ := router.NewRouter("actor", 2048, 512)
-	_ = manager.NewManager(r, wr)
-
 	select {}
 }
diff --git a/services/data_service/internal/control/control.go b/services/data_service/internal/control/control.go
index 9a3bee4..8f87ef2 100644
--- a/services/data_service/internal/control/control.go
+++ b/services/data_service/internal/control/control.go
@@ -1,2 +1,25 @@
 // Package control
 package control
+
+import (
+	"github.com/google/uuid"
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/node"
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/node/processor"
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/router"
+)
+
+type nodeEntry struct {
+	Template            node.Template
+	TemplateFingerprint string
+}
+
+type Controller struct {
+	router            router.Router
+	sourceRegistry    any // source.Registry
+	processorRegistry processor.Registry
+	sinkRegistry      any // sink.Registry
+
+	sourceNodes    map[uuid.UUID]any
+	processorNodes map[uuid.UUID]processor.Processor
+	sinkNodes      map[uuid.UUID]any
+}
diff --git a/services/data_service/internal/control/fingerprint.go b/services/data_service/internal/control/fingerprint.go
new file mode 100644
index 0000000..3078ca9
--- /dev/null
+++ b/services/data_service/internal/control/fingerprint.go
@@ -0,0 +1,43 @@
+package control
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"sort"
+
+	"lukechampine.com/blake3"
+)
+
+func StreamFingerprint(templateFP, outPort string, inMap map[string]string) string {
+	// Sort input keys for determinism.
+	keys := make([]string, 0, len(inMap))
+	for k := range inMap {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	h := blake3.New(32, nil)
+
+	write := func(s string) {
+		var lenbuf [4]byte
+		binary.LittleEndian.PutUint32(lenbuf[:], uint32(len(s)))
+		_, _ = h.Write(lenbuf[:])
+		_, _ = h.Write([]byte(s))
+	}
+
+	// templateFP, outPort, input count, then pairs.
+	write(templateFP)
+	write(outPort)
+
+	var nbuf [4]byte
+	binary.LittleEndian.PutUint32(nbuf[:], uint32(len(keys)))
+	_, _ = h.Write(nbuf[:])
+
+	for _, k := range keys {
+		write(k)
+		write(inMap[k])
+	}
+
+	sum := h.Sum(nil)
+	return hex.EncodeToString(sum)
+}
diff --git a/services/data_service/internal/control/planner.go b/services/data_service/internal/control/planner.go
new file mode 100644
index 0000000..e69de29
diff --git a/services/data_service/internal/control/registry.go b/services/data_service/internal/control/registry.go
new file mode 100644
index 0000000..e69de29
diff --git a/services/data_service/internal/control/wiring.go b/services/data_service/internal/control/wiring.go
new file mode 100644
index 0000000..e69de29
diff --git a/services/data_service/internal/node/exit/session.go b/services/data_service/internal/node/exit/session.go
deleted file mode 100644
index 2a668c7..0000000
--- a/services/data_service/internal/node/exit/session.go
+++ /dev/null
@@ -1,2 +0,0 @@
-// Package exit
-package exit
diff --git a/services/data_service/internal/node/io.go b/services/data_service/internal/node/io.go
index d418de2..06590f1 100644
--- a/services/data_service/internal/node/io.go
+++ b/services/data_service/internal/node/io.go
@@ -5,10 +5,10 @@ import (
 	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/domain"
 )
 
-type In interface {
+type Receiver interface {
 	Receive() (port string, message domain.Message, ok bool)
 }
 
-type Out interface {
+type Sender interface {
 	Send(port string, message domain.Message) error
 }
diff --git a/services/data_service/internal/node/node.go b/services/data_service/internal/node/node.go
new file mode 100644
index 0000000..2bb5f16
--- /dev/null
+++ b/services/data_service/internal/node/node.go
@@ -0,0 +1,16 @@
+package node
+
+type Type string
+
+const (
+	Source    Type = "source"
+	Processor Type = "processor"
+	Sink      Type = "sink"
+)
+
+type Template struct {
+	Kind    Type
+	Type    string
+	Version string
+	Config  string
+}
diff --git a/services/data_service/internal/node/processor/processor.go b/services/data_service/internal/node/processor/processor.go
index 0cc7738..028e348 100644
--- a/services/data_service/internal/node/processor/processor.go
+++ b/services/data_service/internal/node/processor/processor.go
@@ -1,2 +1,18 @@
 // Package processor
 package processor
+
+import (
+	"context"
+
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/node"
+)
+
+type Processor interface {
+	Start(ctx context.Context, cfg string, io IO) error
+	Stop()
+}
+
+type IO interface {
+	node.Receiver
+	node.Sender
+}
diff --git a/services/data_service/internal/node/processor/registry.go b/services/data_service/internal/node/processor/registry.go
index e69de29..6e14d99 100644
--- a/services/data_service/internal/node/processor/registry.go
+++ b/services/data_service/internal/node/processor/registry.go
@@ -0,0 +1,11 @@
+package processor
+
+type Registry struct{}
+
+type Factory interface {
+	New() Processor
+	Type() string
+	Version() string
+
+	TemplateFingerprint(cfg string) (string, error)
+}
diff --git a/services/data_service/internal/node/sink/sink.go b/services/data_service/internal/node/sink/sink.go
new file mode 100644
index 0000000..13972e8
--- /dev/null
+++ b/services/data_service/internal/node/sink/sink.go
@@ -0,0 +1,17 @@
+// Package sink
+package sink
+
+import (
+	"context"
+
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/node"
+)
+
+type Sink interface {
+	Start(ctx context.Context, io IO) error
+	Stop()
+}
+
+type IO interface {
+	node.Sender
+}
diff --git a/services/data_service/internal/node/source/registry.go b/services/data_service/internal/node/source/registry.go
index e69de29..d150341 100644
--- a/services/data_service/internal/node/source/registry.go
+++ b/services/data_service/internal/node/source/registry.go
@@ -0,0 +1 @@
+package source
diff --git a/services/data_service/internal/node/source/source.go b/services/data_service/internal/node/source/source.go
index 4d6e6bc..5f4006c 100644
--- a/services/data_service/internal/node/source/source.go
+++ b/services/data_service/internal/node/source/source.go
@@ -1,2 +1,20 @@
 // Package source
 package source
+
+import (
+	"context"
+
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/node"
+)
+
+type Source interface {
+	Start(ctx context.Context, cfg string, io IO) error
+	Stop()
+
+	Serve(key string) error
+	Unserve(key string) error
+}
+
+type IO interface {
+	node.Sender
+}
diff --git a/services/data_service/internal/router/router.go b/services/data_service/internal/router/router.go
index e69de29..fef5b05 100644
--- a/services/data_service/internal/router/router.go
+++ b/services/data_service/internal/router/router.go
@@ -0,0 +1,9 @@
+// Package router
+package router
+
+import "github.com/google/uuid"
+
+type Router interface {
+	Route(fromNode uuid.UUID, fromOutPort string, toNode uuid.UUID, toInPort string)
+	Unroute(fromNode uuid.UUID, fromOutPort string, toNode uuid.UUID, toInPort string)
+}
diff --git a/services/data_service/internal/router/single/engine.go b/services/data_service/internal/router/single/engine.go
index e69de29..62c7ddc 100644
--- a/services/data_service/internal/router/single/engine.go
+++ b/services/data_service/internal/router/single/engine.go
@@ -0,0 +1,2 @@
+// Package single
+package single