diff --git a/src/ingress/bindings-port.test.ts b/src/ingress/bindings-port.test.ts
new file mode 100644
index 0000000..fcfdde0
--- /dev/null
+++ b/src/ingress/bindings-port.test.ts
@@ -0,0 +1,42 @@
+import { describe, expect, test } from "bun:test";
+import type { GranolaBindingsPort } from "./bindings-port.js";
+
+type FakeBinding = { folderId: string };
+
+function fakePort(): {
+  port: GranolaBindingsPort<FakeBinding>;
+  saved: { tenantId: string; principalId: string; bindings: FakeBinding[] }[];
+} {
+  const saved: { tenantId: string; principalId: string; bindings: FakeBinding[] }[] = [];
+  let stored: { bindings: FakeBinding[]; version: number } | undefined;
+
+  const port: GranolaBindingsPort<FakeBinding> = {
+    async load({ tenantId: _tenantId }) {
+      return stored;
+    },
+    async save({ tenantId, principalId, bindings }) {
+      saved.push({ tenantId, principalId, bindings });
+      stored = { bindings, version: (stored?.version ?? 0) + 1 };
+    },
+  };
+
+  return { port, saved };
+}
+
+describe("GranolaBindingsPort", () => {
+  test("load returns undefined when nothing has ever been saved", async () => {
+    const { port } = fakePort();
+    expect(await port.load({ tenantId: "t1" })).toBeUndefined();
+  });
+
+  test("save then load round-trips the bindings and bumps the version", async () => {
+    const { port, saved } = fakePort();
+    const bindings: FakeBinding[] = [{ folderId: "fol_1" }];
+
+    await port.save({ tenantId: "t1", principalId: "p1", bindings });
+    const loaded = await port.load({ tenantId: "t1" });
+
+    expect(loaded).toEqual({ bindings, version: 1 });
+    expect(saved).toEqual([{ tenantId: "t1", principalId: "p1", bindings }]);
+  });
+});
diff --git a/src/ingress/bindings-port.ts b/src/ingress/bindings-port.ts
new file mode 100644
index 0000000..1194448
--- /dev/null
+++ b/src/ingress/bindings-port.ts
@@ -0,0 +1,19 @@
+// The persistence seam for durable Granola bucket bindings (folder id ->
+// workflow type -> chat channel). This package never persists anything
+// itself — a host composing @corbits/granola/ingress supplies a concrete
+// GranolaBindingsPort backed by whatever storage it already has (a
+// database row, a config artifact, a file — this package doesn't care).
+// Generic over the binding shape so this file has zero dependency on any
+// host-specific or product-specific type.
+
+export interface GranolaBindingsLoadResult<Binding> {
+  bindings: Binding[];
+  version: number;
+}
+
+export interface GranolaBindingsPort<Binding> {
+  /** Current persisted bindings for a tenant, or `undefined` if none have ever been saved. */
+  load(args: { tenantId: string }): Promise<GranolaBindingsLoadResult<Binding> | undefined>;
+  /** Persists a whole new binding set as the tenant's current bindings. */
+  save(args: { tenantId: string; principalId: string; bindings: Binding[] }): Promise<void>;
+}
diff --git a/src/ingress/index.ts b/src/ingress/index.ts
index cab33e3..fa47930 100644
--- a/src/ingress/index.ts
+++ b/src/ingress/index.ts
@@ -5,3 +5,4 @@
 // structurally enforced.
 export { verifyGranolaSignature } from "./webhook.js";
 export type { GranolaIngressOptions, GranolaWebhookHandler } from "./webhook.js";
+export type { GranolaBindingsPort, GranolaBindingsLoadResult } from "./bindings-port.js";