diff --git a/migrations/0069_orb_relay_registration.sql b/migrations/0069_orb_relay_registration.sql
new file mode 100644
index 0000000000..acfffd1a40
--- /dev/null
+++ b/migrations/0069_orb_relay_registration.sql
@@ -0,0 +1,11 @@
+-- Orb event RELAY (#1255): a brokered self-host registers its public relay URL so the central Orb can FORWARD its
+-- repos' webhook events to the container (which reviews + acts via brokered tokens). The container's enrollment
+-- secret is stored ENCRYPTED here (AES-256-GCM via TOKEN_ENCRYPTION_SECRET) so the Orb can HMAC-sign each forwarded
+-- event with it; the container verifies the signature with its own ORB_ENROLLMENT_SECRET. Per-enrollment isolation
+-- (a leak of one container's secret never lets it forge to another), and a DB-only leak can't forge (the encryption
+-- key is a separate secret). The relay URL is SSRF-validated (https, public host) before it's ever forwarded to.
+ALTER TABLE orb_enrollments ADD COLUMN relay_url TEXT;
+ALTER TABLE orb_enrollments ADD COLUMN relay_secret_enc TEXT;
+ALTER TABLE orb_enrollments ADD COLUMN relay_secret_iv TEXT;
+ALTER TABLE orb_enrollments ADD COLUMN relay_secret_salt TEXT;
+ALTER TABLE orb_enrollments ADD COLUMN relay_registered_at TEXT;
diff --git a/src/api/routes.ts b/src/api/routes.ts
index f0e8d49357..b27e393fdf 100644
--- a/src/api/routes.ts
+++ b/src/api/routes.ts
@@ -126,6 +126,7 @@ import { handleOrbIngest, readOrbIngestBody } from "../orb/ingest";
 import { handleOrbWebhook } from "../orb/webhook";
 import { handleOrbOAuthCallback } from "../orb/oauth";
 import { brokerOrbToken, isOrbBrokerEnabled, issueOrbEnrollment } from "../orb/broker";
+import { registerOrbRelay } from "../orb/relay";
 import { computeFleetAnalytics } from "../orb/analytics";
 import { handleMcpRequest } from "../mcp/server";
 import { buildOpenApiSpec } from "../openapi/spec";
@@ -2887,6 +2888,24 @@ export function createApp() {
     return c.json(result);
   });
 
+  // Orb event relay (#1255) — a brokered self-host registers its public relay URL so the Orb can forward its
+  // repos' events to it. Auth: the container's own enrollment secret (Bearer). Flag-gated (404 until enabled).
+  app.post("/v1/orb/relay/register", async (c) => {
+    if (!isOrbBrokerEnabled(c.env)) return c.json({ error: "not_found" }, 404);
+    const auth = c.req.header("authorization") ?? "";
+    const secret = auth.startsWith("Bearer ") ? auth.slice(7).trim() : "";
+    if (!secret) return c.json({ error: "missing_enrollment_secret" }, 401);
+    const body = (await c.req.json().catch(() => null)) as { relayUrl?: unknown } | null;
+    const relayUrl = typeof body?.relayUrl === "string" ? body.relayUrl.trim() : "";
+    if (!relayUrl) return c.json({ error: "missing_relay_url" }, 400);
+    const result = await registerOrbRelay(c.env, secret, relayUrl);
+    if ("error" in result) {
+      const status = result.error === "invalid_enrollment" ? 401 : result.error === "installation_not_eligible" ? 403 : result.error === "encryption_unavailable" ? 500 : 400;
+      return c.json(result, status);
+    }
+    return c.json(result);
+  });
+
   // Gittensory Orb (#1255) — central fleet-calibration collector. Receives anonymized, reversal-aware
   // outcome batches from self-hosted instances. No auth required: all data is HMAC-anonymized by the sender;
   // dedup is enforced via UNIQUE(instance_id, repo_hash, pr_hash) in orb_signals. Rate-limited (strict, #1254).
@@ -4935,6 +4954,7 @@ function requiresApiToken(path: string): boolean {
   if (path === "/v1/orb/webhook") return false;
   if (path === "/v1/orb/oauth/callback") return false;
   if (path === "/v1/orb/token") return false;
+  if (path === "/v1/orb/relay/register") return false;
   if (path === "/v1/orb/ingest") return false;
   if (path.startsWith("/v1/internal/")) return false;
   return path.startsWith("/v1/");
diff --git a/src/auth/rate-limit.ts b/src/auth/rate-limit.ts
index ddcdea4c6b..53b95b33f9 100644
--- a/src/auth/rate-limit.ts
+++ b/src/auth/rate-limit.ts
@@ -101,6 +101,7 @@ export function routeClassForPath(path: string): RateLimitClass {
   if (path === "/v1/orb/webhook") return "strict";
   if (path === "/v1/orb/oauth/callback") return "strict";
   if (path === "/v1/orb/token") return "strict";
+  if (path === "/v1/orb/relay/register") return "strict";
   // Orb telemetry ingest: unauthenticated + write, accepting anonymized batches from untrusted
   // self-host instances. Strict (10/min per IP) caps abuse — legitimate instances export hourly.
   if (path === "/v1/orb/ingest") return "strict";
diff --git a/src/orb/relay.ts b/src/orb/relay.ts
new file mode 100644
index 0000000000..b0c78fb176
--- /dev/null
+++ b/src/orb/relay.ts
@@ -0,0 +1,40 @@
+// Orb event RELAY (#1255) — registration side. A brokered self-host registers its public relay URL so the central
+// Orb can FORWARD its repos' webhook events to the container (which reviews + acts via brokered tokens). The
+// container's enrollment secret is stored ENCRYPTED here (AES-256-GCM via TOKEN_ENCRYPTION_SECRET) so the Orb can
+// HMAC-sign each forwarded event with it; the container verifies the signature with its own ORB_ENROLLMENT_SECRET.
+// Per-enrollment isolation (one container's secret can never forge to another), and a DB-only leak can't forge
+// (the encryption key is a separate secret).
+import { hashToken } from "../auth/security";
+import { isSafeHttpUrl } from "../review/content-lane/safe-url";
+import { encryptSecret } from "../utils/crypto";
+
+export type RegisterResult =
+  | { ok: true; installationId: number }
+  | { error: "invalid_enrollment" | "installation_not_eligible" | "invalid_relay_url" | "encryption_unavailable" };
+
+/** Register (or update) the container's relay target for a valid enrollment. Validates the secret (→ the bound,
+ *  registered, non-suspended install — same gate as the token broker), SSRF-validates the relay URL, then stores
+ *  the URL + the enrollment secret encrypted at rest (for the forward-time HMAC). The container presents its OWN
+ *  plaintext enrollment secret as the Bearer, so this is self-service + bound to that install. */
+export async function registerOrbRelay(env: Env, secret: string, relayUrl: string): Promise<RegisterResult> {
+  const row = await env.DB
+    .prepare("SELECT enroll_id, installation_id, state, revoked_at FROM orb_enrollments WHERE secret_hash = ?")
+    .bind(await hashToken(secret))
+    .first<{ enroll_id: string; installation_id: number; state: string; revoked_at: string | null }>();
+  if (!row || row.state !== "enrolled" || row.revoked_at !== null) return { error: "invalid_enrollment" };
+  const install = await env.DB
+    .prepare("SELECT registered, suspended_at, removed_at FROM orb_github_installations WHERE installation_id = ?")
+    .bind(row.installation_id)
+    .first<{ registered: number; suspended_at: string | null; removed_at: string | null }>();
+  if (!install || install.registered !== 1 || install.suspended_at !== null || install.removed_at !== null) return { error: "installation_not_eligible" };
+  // SSRF guard: the Orb will POST events to this URL — it must be a public https endpoint (no loopback / private /
+  // link-local host), so a registered relay URL can never coerce the Orb into hitting an internal service.
+  if (!isSafeHttpUrl(relayUrl)) return { error: "invalid_relay_url" };
+  if (!env.TOKEN_ENCRYPTION_SECRET) return { error: "encryption_unavailable" };
+  const enc = await encryptSecret(secret, env.TOKEN_ENCRYPTION_SECRET);
+  await env.DB
+    .prepare("UPDATE orb_enrollments SET relay_url = ?, relay_secret_enc = ?, relay_secret_iv = ?, relay_secret_salt = ?, relay_registered_at = CURRENT_TIMESTAMP WHERE enroll_id = ?")
+    .bind(relayUrl, enc.ciphertext, enc.iv, enc.salt, row.enroll_id)
+    .run();
+  return { ok: true, installationId: row.installation_id };
+}
diff --git a/test/integration/orb-relay.test.ts b/test/integration/orb-relay.test.ts
new file mode 100644
index 0000000000..dd81421690
--- /dev/null
+++ b/test/integration/orb-relay.test.ts
@@ -0,0 +1,95 @@
+import { describe, expect, it } from "vitest";
+import { createApp } from "../../src/api/routes";
+import { issueOrbEnrollment } from "../../src/orb/broker";
+import { registerOrbRelay } from "../../src/orb/relay";
+import { createTestEnv, type TestD1Database } from "../helpers/d1";
+
+const db = (e: Env) => e.DB as unknown as TestD1Database;
+const seedInstall = (e: Env, id: number, cols: Record<string, string | number | null> = {}) => {
+  const all: Record<string, string | number | null> = { installation_id: id, registered: 1, ...cols };
+  const keys = Object.keys(all);
+  return db(e).prepare(`INSERT INTO orb_github_installations (${keys.join(", ")}) VALUES (${keys.map(() => "?").join(", ")})`).bind(...keys.map((k) => all[k] as string | number | null)).run();
+};
+const brokeredEnv = () => createTestEnv({ ORB_BROKER_ENABLED: "true", TOKEN_ENCRYPTION_SECRET: "test-encryption-key-material-0001" });
+const enroll = async (e: Env, id: number): Promise<string> => {
+  await seedInstall(e, id);
+  return ((await issueOrbEnrollment(e, id)) as { secret: string }).secret;
+};
+
+describe("registerOrbRelay", () => {
+  it("stores the relay URL + the ENCRYPTED secret for a valid enrollment", async () => {
+    const e = brokeredEnv();
+    const secret = await enroll(e, 700);
+    expect(await registerOrbRelay(e, secret, "https://my-host.example/v1/orb/relay")).toEqual({ ok: true, installationId: 700 });
+    const row = await db(e).prepare("SELECT relay_url, relay_secret_enc, relay_secret_iv FROM orb_enrollments WHERE installation_id=700").first<{ relay_url: string; relay_secret_enc: string; relay_secret_iv: string }>();
+    expect(row?.relay_url).toBe("https://my-host.example/v1/orb/relay");
+    expect(row?.relay_secret_enc).toBeTruthy();
+    expect(row?.relay_secret_iv).toBeTruthy();
+    expect(row?.relay_secret_enc).not.toContain(secret); // stored encrypted, never plaintext
+  });
+
+  it("rejects an unknown / revoked enrollment secret", async () => {
+    expect(await registerOrbRelay(brokeredEnv(), "orbsec_bogus", "https://x.example")).toEqual({ error: "invalid_enrollment" });
+  });
+
+  it("rejects an ineligible install — unregistered, suspended, removed, or deleted", async () => {
+    const e = brokeredEnv();
+    const s1 = await enroll(e, 701);
+    await db(e).prepare("UPDATE orb_github_installations SET registered=0 WHERE installation_id=701").run();
+    expect(await registerOrbRelay(e, s1, "https://x.example")).toEqual({ error: "installation_not_eligible" }); // registered!=1
+    const s2 = await enroll(e, 702);
+    await db(e).prepare("UPDATE orb_github_installations SET suspended_at=CURRENT_TIMESTAMP WHERE installation_id=702").run();
+    expect(await registerOrbRelay(e, s2, "https://x.example")).toEqual({ error: "installation_not_eligible" }); // suspended
+    const s3 = await enroll(e, 703);
+    await db(e).prepare("UPDATE orb_github_installations SET removed_at=CURRENT_TIMESTAMP WHERE installation_id=703").run();
+    expect(await registerOrbRelay(e, s3, "https://x.example")).toEqual({ error: "installation_not_eligible" }); // removed
+    const s4 = await enroll(e, 704);
+    await db(e).prepare("DELETE FROM orb_github_installations WHERE installation_id=704").run();
+    expect(await registerOrbRelay(e, s4, "https://x.example")).toEqual({ error: "installation_not_eligible" }); // !install
+  });
+
+  it("SSRF-rejects a loopback / private / non-https relay URL", async () => {
+    const e = brokeredEnv();
+    const secret = await enroll(e, 705);
+    expect(await registerOrbRelay(e, secret, "http://127.0.0.1/relay")).toEqual({ error: "invalid_relay_url" });
+    expect(await registerOrbRelay(e, secret, "https://localhost/relay")).toEqual({ error: "invalid_relay_url" });
+  });
+
+  it("errors when the server's encryption secret is unavailable", async () => {
+    const e = createTestEnv({ ORB_BROKER_ENABLED: "true" }); // no TOKEN_ENCRYPTION_SECRET
+    const secret = await enroll(e, 706);
+    expect(await registerOrbRelay(e, secret, "https://x.example/relay")).toEqual({ error: "encryption_unavailable" });
+  });
+});
+
+describe("POST /v1/orb/relay/register", () => {
+  const app = createApp();
+
+  it("404s when the broker flag is off (byte-identical deploy)", async () => {
+    expect((await app.request("/v1/orb/relay/register", { method: "POST" }, createTestEnv())).status).toBe(404);
+  });
+
+  it("401 without a secret, 400 without a relayUrl, 200 on success", async () => {
+    const e = brokeredEnv();
+    const secret = await enroll(e, 710);
+    expect((await app.request("/v1/orb/relay/register", { method: "POST" }, e)).status).toBe(401);
+    expect((await app.request("/v1/orb/relay/register", { method: "POST", headers: { authorization: `Bearer ${secret}` }, body: "{bad" }, e)).status).toBe(400); // unparseable body → catch → null → 400
+    const ok = await app.request("/v1/orb/relay/register", { method: "POST", headers: { authorization: `Bearer ${secret}` }, body: JSON.stringify({ relayUrl: "https://my-host.example/v1/orb/relay" }) }, e);
+    expect(ok.status).toBe(200);
+    expect(await ok.json()).toMatchObject({ ok: true, installationId: 710 });
+  });
+
+  it("maps each failure to its status: 401 bad secret, 403 ineligible, 400 SSRF, 500 no-encryption", async () => {
+    const e = brokeredEnv();
+    const sBad = "Bearer orbsec_bad";
+    expect((await app.request("/v1/orb/relay/register", { method: "POST", headers: { authorization: sBad }, body: JSON.stringify({ relayUrl: "https://x.example" }) }, e)).status).toBe(401);
+    const s1 = await enroll(e, 711);
+    expect((await app.request("/v1/orb/relay/register", { method: "POST", headers: { authorization: `Bearer ${s1}` }, body: JSON.stringify({ relayUrl: "http://127.0.0.1" }) }, e)).status).toBe(400);
+    const s2 = await enroll(e, 712);
+    await db(e).prepare("UPDATE orb_github_installations SET registered=0 WHERE installation_id=712").run();
+    expect((await app.request("/v1/orb/relay/register", { method: "POST", headers: { authorization: `Bearer ${s2}` }, body: JSON.stringify({ relayUrl: "https://x.example" }) }, e)).status).toBe(403);
+    const noEnc = createTestEnv({ ORB_BROKER_ENABLED: "true" });
+    const s3 = await enroll(noEnc, 713);
+    expect((await app.request("/v1/orb/relay/register", { method: "POST", headers: { authorization: `Bearer ${s3}` }, body: JSON.stringify({ relayUrl: "https://x.example/relay" }) }, noEnc)).status).toBe(500);
+  });
+});