diff --git a/bun.lock b/bun.lock
index 8860431..796f356 100644
--- a/bun.lock
+++ b/bun.lock
@@ -40,7 +40,7 @@
       "version": "0.1.0",
       "dependencies": {
         "@shade/core": "workspace:*",
-        "hono": "^4.0.0",
+        "hono": "^4.12.12",
       },
     },
     "packages/shade-transport": {
diff --git a/packages/shade-proto/src/index.ts b/packages/shade-proto/src/index.ts
new file mode 100644
index 0000000..49153f5
--- /dev/null
+++ b/packages/shade-proto/src/index.ts
@@ -0,0 +1 @@
+export { encodeEnvelope, decodeEnvelope, encodePreKeyMessage, encodeRatchetMessage } from './wire.js';
diff --git a/packages/shade-proto/src/wire.ts b/packages/shade-proto/src/wire.ts
new file mode 100644
index 0000000..7256506
--- /dev/null
+++ b/packages/shade-proto/src/wire.ts
@@ -0,0 +1,172 @@
+/**
+ * Shade Wire Format — compact binary encoding for protocol messages.
+ *
+ * Format: [version:1][type:1][payload...]
+ *
+ * Types:
+ *   0x01 = PreKeyMessage
+ *   0x02 = RatchetMessage
+ *
+ * All multi-byte integers are big-endian.
+ * All byte arrays are length-prefixed (2-byte length + data).
+ */
+
+import type { PreKeyMessage, RatchetMessage, ShadeEnvelope } from '@shade/core';
+
+const VERSION = 0x01;
+
+const TYPE_PREKEY = 0x01;
+const TYPE_RATCHET = 0x02;
+
+// ─── Encode ──────────────────────────────────────────────────
+
+export function encodeEnvelope(envelope: ShadeEnvelope): Uint8Array {
+  if (envelope.type === 'prekey') {
+    return encodePreKeyMessage(envelope.content as PreKeyMessage);
+  }
+  return encodeRatchetMessage(envelope.content as RatchetMessage);
+}
+
+export function encodePreKeyMessage(msg: PreKeyMessage): Uint8Array {
+  const ratchetBytes = encodeRatchetMessageInner(msg.message);
+  const parts: Uint8Array[] = [];
+
+  // Header
+  parts.push(new Uint8Array([VERSION, TYPE_PREKEY]));
+
+  // registrationId (4 bytes)
+  parts.push(uint32(msg.registrationId));
+
+  // preKeyId (4 bytes, 0xFFFFFFFF = none)
+  parts.push(uint32(msg.preKeyId ?? 0xFFFFFFFF));
+
+  // signedPreKeyId (4 bytes)
+  parts.push(uint32(msg.signedPreKeyId));
+
+  // ephemeralKey (length-prefixed)
+  parts.push(lpBytes(msg.ephemeralKey));
+
+  // identityDHKey (length-prefixed)
+  parts.push(lpBytes(msg.identityDHKey));
+
+  // embedded ratchet message (length-prefixed)
+  parts.push(lpBytes(ratchetBytes));
+
+  return concat(parts);
+}
+
+export function encodeRatchetMessage(msg: RatchetMessage): Uint8Array {
+  const parts: Uint8Array[] = [];
+  parts.push(new Uint8Array([VERSION, TYPE_RATCHET]));
+  parts.push(encodeRatchetMessageInner(msg));
+  return concat(parts);
+}
+
+function encodeRatchetMessageInner(msg: RatchetMessage): Uint8Array {
+  const parts: Uint8Array[] = [];
+  parts.push(lpBytes(msg.dhPublicKey));
+  parts.push(uint32(msg.previousCounter));
+  parts.push(uint32(msg.counter));
+  parts.push(lpBytes(msg.ciphertext));
+  parts.push(lpBytes(msg.nonce));
+  return concat(parts);
+}
+
+// ─── Decode ──────────────────────────────────────────────────
+
+export function decodeEnvelope(data: Uint8Array): ShadeEnvelope {
+  if (data.length < 2) throw new Error('Too short');
+  const version = data[0];
+  if (version !== VERSION) throw new Error(`Unknown version: ${version}`);
+
+  const type = data[1];
+  const payload = data.slice(2);
+
+  if (type === TYPE_PREKEY) {
+    const msg = decodePreKeyMessageInner(payload);
+    return { type: 'prekey', content: msg, timestamp: 0, senderAddress: '' };
+  }
+  if (type === TYPE_RATCHET) {
+    const msg = decodeRatchetMessageInner(payload, 0).value;
+    return { type: 'ratchet', content: msg, timestamp: 0, senderAddress: '' };
+  }
+  throw new Error(`Unknown type: ${type}`);
+}
+
+function decodePreKeyMessageInner(data: Uint8Array): PreKeyMessage {
+  let offset = 0;
+
+  const registrationId = readUint32(data, offset); offset += 4;
+  const preKeyIdRaw = readUint32(data, offset); offset += 4;
+  const preKeyId = preKeyIdRaw === 0xFFFFFFFF ? undefined : preKeyIdRaw;
+  const signedPreKeyId = readUint32(data, offset); offset += 4;
+
+  const ephemeral = readLP(data, offset); offset = ephemeral.end;
+  const identityDH = readLP(data, offset); offset = identityDH.end;
+  const ratchetData = readLP(data, offset); offset = ratchetData.end;
+
+  const ratchet = decodeRatchetMessageInner(ratchetData.value, 0);
+
+  return {
+    registrationId,
+    preKeyId,
+    signedPreKeyId,
+    ephemeralKey: ephemeral.value,
+    identityDHKey: identityDH.value,
+    message: ratchet.value,
+  };
+}
+
+function decodeRatchetMessageInner(data: Uint8Array, offset: number): { value: RatchetMessage; end: number } {
+  const dhPub = readLP(data, offset); offset = dhPub.end;
+  const prevCounter = readUint32(data, offset); offset += 4;
+  const counter = readUint32(data, offset); offset += 4;
+  const ciphertext = readLP(data, offset); offset = ciphertext.end;
+  const nonce = readLP(data, offset); offset = nonce.end;
+
+  return {
+    value: {
+      dhPublicKey: dhPub.value,
+      previousCounter: prevCounter,
+      counter,
+      ciphertext: ciphertext.value,
+      nonce: nonce.value,
+    },
+    end: offset,
+  };
+}
+
+// ─── Helpers ─────────────────────────────────────────────────
+
+function uint32(n: number): Uint8Array {
+  const buf = new Uint8Array(4);
+  new DataView(buf.buffer).setUint32(0, n, false);
+  return buf;
+}
+
+function lpBytes(data: Uint8Array): Uint8Array {
+  const len = new Uint8Array(2);
+  new DataView(len.buffer).setUint16(0, data.length, false);
+  return concat([len, data]);
+}
+
+function readUint32(data: Uint8Array, offset: number): number {
+  return new DataView(data.buffer, data.byteOffset + offset).getUint32(0, false);
+}
+
+function readLP(data: Uint8Array, offset: number): { value: Uint8Array; end: number } {
+  const len = new DataView(data.buffer, data.byteOffset + offset).getUint16(0, false);
+  const value = data.slice(offset + 2, offset + 2 + len);
+  return { value, end: offset + 2 + len };
+}
+
+function concat(parts: Uint8Array[]): Uint8Array {
+  const total = parts.reduce((sum, p) => sum + p.length, 0);
+  const result = new Uint8Array(total);
+  let offset = 0;
+  for (const p of parts) {
+    result.set(p, offset);
+    offset += p.length;
+  }
+  return result;
+}
diff --git a/packages/shade-proto/tests/wire.test.ts b/packages/shade-proto/tests/wire.test.ts
new file mode 100644
index 0000000..b9d6d36
--- /dev/null
+++ b/packages/shade-proto/tests/wire.test.ts
@@ -0,0 +1,185 @@
+import { describe, test, expect } from 'bun:test';
+import { encodeEnvelope, decodeEnvelope, encodePreKeyMessage, encodeRatchetMessage } from '../src/index.js';
+import type { PreKeyMessage, RatchetMessage, ShadeEnvelope } from '@shade/core';
+
+function randBytes(n: number): Uint8Array {
+  const buf = new Uint8Array(n);
+  crypto.getRandomValues(buf);
+  return buf;
+}
+
+function makeRatchetMessage(): RatchetMessage {
+  return {
+    dhPublicKey: randBytes(32),
+    previousCounter: 42,
+    counter: 7,
+    ciphertext: randBytes(64),
+    nonce: randBytes(12),
+  };
+}
+
+function makePreKeyMessage(): PreKeyMessage {
+  return {
+    registrationId: 12345,
+    preKeyId: 100,
+    signedPreKeyId: 1,
+    ephemeralKey: randBytes(32),
+    identityDHKey: randBytes(32),
+    message: makeRatchetMessage(),
+  };
+}
+
+describe('Wire Format', () => {
+  // ─── RatchetMessage ────────────────────────────────────────
+
+  describe('RatchetMessage', () => {
+    test('encode/decode roundtrip', () => {
+      const msg = makeRatchetMessage();
+      const envelope: ShadeEnvelope = {
+        type: 'ratchet',
+        content: msg,
+        timestamp: Date.now(),
+        senderAddress: 'alice',
+      };
+
+      const encoded = encodeEnvelope(envelope);
+      const decoded = decodeEnvelope(encoded);
+
+      expect(decoded.type).toBe('ratchet');
+      const rm = decoded.content as RatchetMessage;
+      expect(rm.dhPublicKey).toEqual(msg.dhPublicKey);
+      expect(rm.previousCounter).toBe(42);
+      expect(rm.counter).toBe(7);
+      expect(rm.ciphertext).toEqual(msg.ciphertext);
+      expect(rm.nonce).toEqual(msg.nonce);
+    });
+
+    test('compact size (smaller than JSON)', () => {
+      const msg = makeRatchetMessage();
+      const envelope: ShadeEnvelope = {
+        type: 'ratchet',
+        content: msg,
+        timestamp: 0,
+        senderAddress: '',
+      };
+
+      const binary = encodeEnvelope(envelope);
+      const json = new TextEncoder().encode(JSON.stringify(envelope));
+
+      // Binary should be significantly smaller
+      expect(binary.length).toBeLessThan(json.length);
+    });
+  });
+
+  // ─── PreKeyMessage ─────────────────────────────────────────
+
+  describe('PreKeyMessage', () => {
+    test('encode/decode roundtrip with preKeyId', () => {
+      const msg = makePreKeyMessage();
+      const envelope: ShadeEnvelope = {
+        type: 'prekey',
+        content: msg,
+        timestamp: Date.now(),
+        senderAddress: 'alice',
+      };
+
+      const encoded = encodeEnvelope(envelope);
+      const decoded = decodeEnvelope(encoded);
+
+      expect(decoded.type).toBe('prekey');
+      const pm = decoded.content as PreKeyMessage;
+      expect(pm.registrationId).toBe(12345);
+      expect(pm.preKeyId).toBe(100);
+      expect(pm.signedPreKeyId).toBe(1);
+      expect(pm.ephemeralKey).toEqual(msg.ephemeralKey);
+      expect(pm.identityDHKey).toEqual(msg.identityDHKey);
+
+      // Nested ratchet message
+      expect(pm.message.dhPublicKey).toEqual(msg.message.dhPublicKey);
+      expect(pm.message.counter).toBe(msg.message.counter);
+      expect(pm.message.ciphertext).toEqual(msg.message.ciphertext);
+      expect(pm.message.nonce).toEqual(msg.message.nonce);
+    });
+
+    test('encode/decode roundtrip without preKeyId', () => {
+      const msg = makePreKeyMessage();
+      msg.preKeyId = undefined;
+
+      const envelope: ShadeEnvelope = {
+        type: 'prekey',
+        content: msg,
+        timestamp: 0,
+        senderAddress: '',
+      };
+
+      const encoded = encodeEnvelope(envelope);
+      const decoded = decodeEnvelope(encoded);
+
+      const pm = decoded.content as PreKeyMessage;
+      expect(pm.preKeyId).toBeUndefined();
+    });
+  });
+
+  // ─── Edge Cases ────────────────────────────────────────────
+
+  describe('edge cases', () => {
+    test('empty ciphertext', () => {
+      const msg: RatchetMessage = {
+        dhPublicKey: randBytes(32),
+        previousCounter: 0,
+        counter: 0,
+        ciphertext: new Uint8Array(0),
+        nonce: randBytes(12),
+      };
+
+      const encoded = encodeRatchetMessage(msg);
+      const decoded = decodeEnvelope(encoded);
+      expect((decoded.content as RatchetMessage).ciphertext.length).toBe(0);
+    });
+
+    test('large ciphertext (10KB)', () => {
+      const msg: RatchetMessage = {
+        dhPublicKey: randBytes(32),
+        previousCounter: 0,
+        counter: 0,
+        ciphertext: randBytes(10240),
+        nonce: randBytes(12),
+      };
+
+      const encoded = encodeRatchetMessage(msg);
+      const decoded = decodeEnvelope(encoded);
+      expect((decoded.content as RatchetMessage).ciphertext).toEqual(msg.ciphertext);
+    });
+
+    test('max counter values', () => {
+      const msg: RatchetMessage = {
+        dhPublicKey: randBytes(32),
+        previousCounter: 0xFFFFFFFF - 1,
+        counter: 0xFFFFFFFF - 1,
+        ciphertext: randBytes(16),
+        nonce: randBytes(12),
+      };
+
+      const encoded = encodeRatchetMessage(msg);
+      const decoded = decodeEnvelope(encoded);
+      const rm = decoded.content as RatchetMessage;
+      expect(rm.previousCounter).toBe(0xFFFFFFFF - 1);
+      expect(rm.counter).toBe(0xFFFFFFFF - 1);
+    });
+
+    test('rejects unknown version', () => {
+      const data = new Uint8Array([0xFF, 0x01]);
+      expect(() => decodeEnvelope(data)).toThrow('Unknown version');
+    });
+
+    test('rejects unknown type', () => {
+      const data = new Uint8Array([0x01, 0xFF]);
+      expect(() => decodeEnvelope(data)).toThrow('Unknown type');
+    });
+
+    test('rejects too-short data', () => {
+      expect(() => decodeEnvelope(new Uint8Array([0x01]))).toThrow('Too short');
+      expect(() => decodeEnvelope(new Uint8Array([]))).toThrow('Too short');
+    });
+  });
+});
diff --git a/packages/shade-proto/tsconfig.json b/packages/shade-proto/tsconfig.json
new file mode 100644
index 0000000..a086b14
--- /dev/null
+++ b/packages/shade-proto/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src"
+  },
+  "include": ["src"]
+}
diff --git a/packages/shade-server/Dockerfile b/packages/shade-server/Dockerfile
new file mode 100644
index 0000000..097289a
--- /dev/null
+++ b/packages/shade-server/Dockerfile
@@ -0,0 +1,11 @@
+FROM oven/bun:1-alpine
+
+WORKDIR /app
+COPY package.json bun.lock ./
+RUN bun install --production --frozen-lockfile
+
+COPY src/ src/
+
+EXPOSE 3900
+
+CMD ["bun", "run", "src/standalone.ts"]
diff --git a/packages/shade-server/package.json b/packages/shade-server/package.json
index 2d4b827..aa41aa8 100644
--- a/packages/shade-server/package.json
+++ b/packages/shade-server/package.json
@@ -6,6 +6,6 @@
   "types": "src/index.ts",
   "dependencies": {
     "@shade/core": "workspace:*",
-    "hono": "^4.0.0"
+    "hono": "^4.12.12"
   }
 }
diff --git a/packages/shade-server/src/index.ts b/packages/shade-server/src/index.ts
new file mode 100644
index 0000000..9b6bd6b
--- /dev/null
+++ b/packages/shade-server/src/index.ts
@@ -0,0 +1,28 @@
+import { Hono } from 'hono';
+import { createPrekeyRoutes } from './routes.js';
+import { MemoryPrekeyStore } from './memory-store.js';
+import type { PrekeyStore } from './store.js';
+
+export { createPrekeyRoutes } from './routes.js';
+export { MemoryPrekeyStore } from './memory-store.js';
+export type { PrekeyStore } from './store.js';
+
+/**
+ * Create a standalone Shade Prekey Server.
+ *
+ * Can be used standalone (Docker) or embedded in another Hono app.
+ *
+ * Standalone:
+ *   const server = createPrekeyServer();
+ *   export default { port: 3900, fetch: server.fetch };
+ *
+ * Embedded:
+ *   const app = new Hono();
+ *   app.route('/shade', createPrekeyServer());
+ */
+export function createPrekeyServer(options?: {
+  store?: PrekeyStore;
+}): Hono {
+  const store = options?.store ?? new MemoryPrekeyStore();
+  return createPrekeyRoutes(store);
+}
diff --git a/packages/shade-server/src/memory-store.ts b/packages/shade-server/src/memory-store.ts
new file mode 100644
index 0000000..5252ef8
--- /dev/null
+++ b/packages/shade-server/src/memory-store.ts
@@ -0,0 +1,64 @@
+import type { PrekeyStore } from './store.js';
+
+interface IdentityRecord {
+  identitySigningKey: Uint8Array;
+  identityDHKey: Uint8Array;
+}
+
+interface SignedPreKeyRecord {
+  keyId: number;
+  publicKey: Uint8Array;
+  signature: Uint8Array;
+}
+
+interface OneTimePreKeyRecord {
+  keyId: number;
+  publicKey: Uint8Array;
+}
+
+/**
+ * In-memory PrekeyStore for testing and embedded use.
+ */
+export class MemoryPrekeyStore implements PrekeyStore {
+  private identities = new Map<string, IdentityRecord>();
+  private signedPreKeys = new Map<string, SignedPreKeyRecord>();
+  private oneTimePreKeys = new Map<string, OneTimePreKeyRecord[]>();
+
+  async saveIdentity(address: string, identitySigningKey: Uint8Array, identityDHKey: Uint8Array): Promise<void> {
+    this.identities.set(address, { identitySigningKey, identityDHKey });
+  }
+
+  async getIdentity(address: string): Promise<IdentityRecord | null> {
+    return this.identities.get(address) ?? null;
+  }
+
+  async saveSignedPreKey(address: string, keyId: number, publicKey: Uint8Array, signature: Uint8Array): Promise<void> {
+    this.signedPreKeys.set(address, { keyId, publicKey, signature });
+  }
+
+  async getSignedPreKey(address: string): Promise<SignedPreKeyRecord | null> {
+    return this.signedPreKeys.get(address) ?? null;
+  }
+
+  async saveOneTimePreKeys(address: string, keys: Array<{ keyId: number; publicKey: Uint8Array }>): Promise<void> {
+    const existing = this.oneTimePreKeys.get(address) ?? [];
+    existing.push(...keys);
+    this.oneTimePreKeys.set(address, existing);
+  }
+
+  async consumeOneTimePreKey(address: string): Promise<OneTimePreKeyRecord | null> {
+    const keys = this.oneTimePreKeys.get(address);
+    if (!keys || keys.length === 0) return null;
+    return keys.shift()!;
+  }
+
+  async getOneTimePreKeyCount(address: string): Promise<number> {
+    return this.oneTimePreKeys.get(address)?.length ?? 0;
+  }
+
+  async deleteAll(address: string): Promise<void> {
+    this.identities.delete(address);
+    this.signedPreKeys.delete(address);
+    this.oneTimePreKeys.delete(address);
+  }
+}
diff --git a/packages/shade-server/src/routes.ts b/packages/shade-server/src/routes.ts
new file mode 100644
index 0000000..7b46815
--- /dev/null
+++ b/packages/shade-server/src/routes.ts
@@ -0,0 +1,130 @@
+import { Hono } from 'hono';
+import type { PrekeyStore } from './store.js';
+
+/**
+ * Create the Shade Prekey Server Hono app.
+ *
+ * Routes:
+ *   POST   /v1/keys/register        — Register identity + upload prekey bundle
+ *   GET    /v1/keys/bundle/:address  — Fetch a prekey bundle (consumes one OTP key)
+ *   POST   /v1/keys/replenish       — Upload additional one-time prekeys
+ *   GET    /v1/keys/count/:address   — Get remaining one-time prekey count
+ *   DELETE /v1/keys/:address         — Unregister (delete all keys)
+ */
+export function createPrekeyRoutes(store: PrekeyStore): Hono {
+  const app = new Hono();
+
+  // ─── Register ──────────────────────────────────────────────
+  app.post('/v1/keys/register', async (c) => {
+    const body = await c.req.json();
+    const { address, identitySigningKey, identityDHKey, signedPreKey, oneTimePreKeys } = body;
+
+    if (!address || !identitySigningKey || !identityDHKey || !signedPreKey) {
+      return c.json({ error: 'Missing required fields' }, 400);
+    }
+
+    // Decode base64 keys
+    const signingKey = b64ToBytes(identitySigningKey);
+    const dhKey = b64ToBytes(identityDHKey);
+
+    await store.saveIdentity(address, signingKey, dhKey);
+    await store.saveSignedPreKey(
+      address,
+      signedPreKey.keyId,
+      b64ToBytes(signedPreKey.publicKey),
+      b64ToBytes(signedPreKey.signature),
+    );
+
+    if (oneTimePreKeys && Array.isArray(oneTimePreKeys)) {
+      const keys = oneTimePreKeys.map((k: any) => ({
+        keyId: k.keyId,
+        publicKey: b64ToBytes(k.publicKey),
+      }));
+      await store.saveOneTimePreKeys(address, keys);
+    }
+
+    return c.json({ ok: true });
+  });
+
+  // ─── Fetch Bundle ──────────────────────────────────────────
+  app.get('/v1/keys/bundle/:address', async (c) => {
+    const address = c.req.param('address');
+
+    const identity = await store.getIdentity(address);
+    if (!identity) {
+      return c.json({ error: 'Address not found' }, 404);
+    }
+
+    const signedPreKey = await store.getSignedPreKey(address);
+    if (!signedPreKey) {
+      return c.json({ error: 'No signed prekey' }, 404);
+    }
+
+    // Consume one one-time prekey (if available)
+    const oneTimePreKey = await store.consumeOneTimePreKey(address);
+
+    const bundle: any = {
+      identitySigningKey: bytesToB64(identity.identitySigningKey),
+      identityDHKey: bytesToB64(identity.identityDHKey),
+      signedPreKey: {
+        keyId: signedPreKey.keyId,
+        publicKey: bytesToB64(signedPreKey.publicKey),
+        signature: bytesToB64(signedPreKey.signature),
+      },
+    };
+
+    if (oneTimePreKey) {
+      bundle.oneTimePreKey = {
+        keyId: oneTimePreKey.keyId,
+        publicKey: bytesToB64(oneTimePreKey.publicKey),
+      };
+    }
+
+    return c.json(bundle);
+  });
+
+  // ─── Replenish One-Time Prekeys ────────────────────────────
+  app.post('/v1/keys/replenish', async (c) => {
+    const body = await c.req.json();
+    const { address, oneTimePreKeys } = body;
+
+    if (!address || !oneTimePreKeys || !Array.isArray(oneTimePreKeys)) {
+      return c.json({ error: 'Missing address or oneTimePreKeys' }, 400);
+    }
+
+    const keys = oneTimePreKeys.map((k: any) => ({
+      keyId: k.keyId,
+      publicKey: b64ToBytes(k.publicKey),
+    }));
+    await store.saveOneTimePreKeys(address, keys);
+
+    const count = await store.getOneTimePreKeyCount(address);
+    return c.json({ ok: true, remaining: count });
+  });
+
+  // ─── Get Count ─────────────────────────────────────────────
+  app.get('/v1/keys/count/:address', async (c) => {
+    const address = c.req.param('address');
+    const count = await store.getOneTimePreKeyCount(address);
+    return c.json({ count });
+  });
+
+  // ─── Delete ────────────────────────────────────────────────
+  app.delete('/v1/keys/:address', async (c) => {
+    const address = c.req.param('address');
+    await store.deleteAll(address);
+    return c.json({ ok: true });
+  });
+
+  return app;
+}
+
+// ─── Base64 helpers ──────────────────────────────────────────
+
+function bytesToB64(bytes: Uint8Array): string {
+  return Buffer.from(bytes).toString('base64');
+}
+
+function b64ToBytes(b64: string): Uint8Array {
+  return new Uint8Array(Buffer.from(b64, 'base64'));
+}
diff --git a/packages/shade-server/src/standalone.ts b/packages/shade-server/src/standalone.ts
new file mode 100644
index 0000000..6fd4bf9
--- /dev/null
+++ b/packages/shade-server/src/standalone.ts
@@ -0,0 +1,10 @@
+import { createPrekeyServer } from './index.js';
+
+const server = createPrekeyServer();
+
+export default {
+  port: Number(process.env.PORT ?? 3900),
+  fetch: server.fetch,
+};
+
+console.log(`Shade Prekey Server listening on port ${process.env.PORT ?? 3900}`);
diff --git a/packages/shade-server/src/store.ts b/packages/shade-server/src/store.ts
new file mode 100644
index 0000000..e873683
--- /dev/null
+++ b/packages/shade-server/src/store.ts
@@ -0,0 +1,48 @@
+/**
+ * PrekeyStore — server-side storage interface for prekey bundles.
+ *
+ * The prekey server stores public keys only (never private keys).
+ */
+export interface PrekeyStore {
+  /** Save or update an identity for an address */
+  saveIdentity(
+    address: string,
+    identitySigningKey: Uint8Array,
+    identityDHKey: Uint8Array,
+  ): Promise<void>;
+
+  /** Get an identity by address */
+  getIdentity(
+    address: string,
+  ): Promise<{ identitySigningKey: Uint8Array; identityDHKey: Uint8Array } | null>;
+
+  /** Save or update a signed prekey for an address */
+  saveSignedPreKey(
+    address: string,
+    keyId: number,
+    publicKey: Uint8Array,
+    signature: Uint8Array,
+  ): Promise<void>;
+
+  /** Get the current signed prekey for an address */
+  getSignedPreKey(
+    address: string,
+  ): Promise<{ keyId: number; publicKey: Uint8Array; signature: Uint8Array } | null>;
+
+  /** Add one-time prekeys for an address */
+  saveOneTimePreKeys(
+    address: string,
+    keys: Array<{ keyId: number; publicKey: Uint8Array }>,
+  ): Promise<void>;
+
+  /** Consume (pop) one one-time prekey for an address. Returns null if none left. */
+  consumeOneTimePreKey(
+    address: string,
+  ): Promise<{ keyId: number; publicKey: Uint8Array } | null>;
+
+  /** Get remaining one-time prekey count for an address */
+  getOneTimePreKeyCount(address: string): Promise<number>;
+
+  /** Delete all keys for an address */
+  deleteAll(address: string): Promise<void>;
+}
diff --git a/packages/shade-server/tests/server.test.ts b/packages/shade-server/tests/server.test.ts
new file mode 100644
index 0000000..558ed9d
--- /dev/null
+++ b/packages/shade-server/tests/server.test.ts
@@ -0,0 +1,231 @@
+import { describe, test, expect, beforeEach } from 'bun:test';
+import { createPrekeyServer, MemoryPrekeyStore } from '../src/index.js';
+import type { PrekeyStore } from '../src/index.js';
+
+function b64(bytes: Uint8Array): string {
+  return Buffer.from(bytes).toString('base64');
+}
+
+function randBytes(n: number): Uint8Array {
+  const buf = new Uint8Array(n);
+  crypto.getRandomValues(buf);
+  return buf;
+}
+
+describe('Shade Prekey Server', () => {
+  let store: PrekeyStore;
+  let app: ReturnType<typeof createPrekeyServer>;
+
+  beforeEach(() => {
+    store = new MemoryPrekeyStore();
+    app = createPrekeyServer({ store });
+  });
+
+  function req(method: string, path: string, body?: any) {
+    const init: RequestInit = { method, headers: { 'Content-Type': 'application/json' } };
+    if (body) init.body = JSON.stringify(body);
+    return app.request(path, init);
+  }
+
+  // ─── Registration ──────────────────────────────────────────
+
+  describe('POST /v1/keys/register', () => {
+    test('registers identity and signed prekey', async () => {
+      const res = await req('POST', '/v1/keys/register', {
+        address: 'alice',
+        identitySigningKey: b64(randBytes(32)),
+        identityDHKey: b64(randBytes(32)),
+        signedPreKey: {
+          keyId: 1,
+          publicKey: b64(randBytes(32)),
+          signature: b64(randBytes(64)),
+        },
+      });
+      expect(res.status).toBe(200);
+      expect(await res.json()).toEqual({ ok: true });
+    });
+
+    test('registers with one-time prekeys', async () => {
+      const res = await req('POST', '/v1/keys/register', {
+        address: 'alice',
+        identitySigningKey: b64(randBytes(32)),
+        identityDHKey: b64(randBytes(32)),
+        signedPreKey: {
+          keyId: 1,
+          publicKey: b64(randBytes(32)),
+          signature: b64(randBytes(64)),
+        },
+        oneTimePreKeys: [
+          { keyId: 100, publicKey: b64(randBytes(32)) },
+          { keyId: 101, publicKey: b64(randBytes(32)) },
+          { keyId: 102, publicKey: b64(randBytes(32)) },
+        ],
+      });
+      expect(res.status).toBe(200);
+
+      // Verify count
+      const countRes = await req('GET', '/v1/keys/count/alice');
+      expect((await countRes.json()).count).toBe(3);
+    });
+
+    test('rejects missing fields', async () => {
+      const res = await req('POST', '/v1/keys/register', { address: 'alice' });
+      expect(res.status).toBe(400);
+    });
+  });
+
+  // ─── Fetch Bundle ──────────────────────────────────────────
+
+  describe('GET /v1/keys/bundle/:address', () => {
+    test('returns bundle with one-time prekey', async () => {
+      // Register first
+      const sigKey = b64(randBytes(32));
+      const dhKey = b64(randBytes(32));
+      const spkPub = b64(randBytes(32));
+      const spkSig = b64(randBytes(64));
+      const otpkPub = b64(randBytes(32));
+
+      await req('POST', '/v1/keys/register', {
+        address: 'bob',
+        identitySigningKey: sigKey,
+        identityDHKey: dhKey,
+        signedPreKey: { keyId: 1, publicKey: spkPub, signature: spkSig },
+        oneTimePreKeys: [{ keyId: 100, publicKey: otpkPub }],
+      });
+
+      const res = await req('GET', '/v1/keys/bundle/bob');
+      expect(res.status).toBe(200);
+
+      const bundle = await res.json();
+      expect(bundle.identitySigningKey).toBe(sigKey);
+      expect(bundle.identityDHKey).toBe(dhKey);
+      expect(bundle.signedPreKey.keyId).toBe(1);
+      expect(bundle.signedPreKey.publicKey).toBe(spkPub);
+      expect(bundle.signedPreKey.signature).toBe(spkSig);
+      expect(bundle.oneTimePreKey.keyId).toBe(100);
+      expect(bundle.oneTimePreKey.publicKey).toBe(otpkPub);
+    });
+
+    test('returns bundle without one-time prekey when depleted', async () => {
+      await req('POST', '/v1/keys/register', {
+        address: 'bob',
+        identitySigningKey: b64(randBytes(32)),
+        identityDHKey: b64(randBytes(32)),
+        signedPreKey: { keyId: 1, publicKey: b64(randBytes(32)), signature: b64(randBytes(64)) },
+      });
+
+      const res = await req('GET', '/v1/keys/bundle/bob');
+      expect(res.status).toBe(200);
+
+      const bundle = await res.json();
+      expect(bundle.oneTimePreKey).toBeUndefined();
+    });
+
+    test('consumes one-time prekeys on each fetch', async () => {
+      await req('POST', '/v1/keys/register', {
+        address: 'bob',
+        identitySigningKey: b64(randBytes(32)),
+        identityDHKey: b64(randBytes(32)),
+        signedPreKey: { keyId: 1, publicKey: b64(randBytes(32)), signature: b64(randBytes(64)) },
+        oneTimePreKeys: [
+          { keyId: 100, publicKey: b64(randBytes(32)) },
+          { keyId: 101, publicKey: b64(randBytes(32)) },
+        ],
+      });
+
+      // First fetch consumes key 100
+      const res1 = await req('GET', '/v1/keys/bundle/bob');
+      expect((await res1.json()).oneTimePreKey.keyId).toBe(100);
+
+      // Second fetch consumes key 101
+      const res2 = await req('GET', '/v1/keys/bundle/bob');
+      expect((await res2.json()).oneTimePreKey.keyId).toBe(101);
+
+      // Third fetch has none left
+      const res3 = await req('GET', '/v1/keys/bundle/bob');
+      expect((await res3.json()).oneTimePreKey).toBeUndefined();
+
+      // Count should be 0
+      const countRes = await req('GET', '/v1/keys/count/bob');
+      expect((await countRes.json()).count).toBe(0);
+    });
+
+    test('404 for unknown address', async () => {
+      const res = await req('GET', '/v1/keys/bundle/nobody');
+      expect(res.status).toBe(404);
+    });
+  });
+
+  // ─── Replenish ─────────────────────────────────────────────
+
+  describe('POST /v1/keys/replenish', () => {
+    test('adds more one-time prekeys', async () => {
+      await req('POST', '/v1/keys/register', {
+        address: 'bob',
+        identitySigningKey: b64(randBytes(32)),
+        identityDHKey: b64(randBytes(32)),
+        signedPreKey: { keyId: 1, publicKey: b64(randBytes(32)), signature: b64(randBytes(64)) },
+        oneTimePreKeys: [{ keyId: 100, publicKey: b64(randBytes(32)) }],
+      });
+
+      const res = await req('POST', '/v1/keys/replenish', {
+        address: 'bob',
+        oneTimePreKeys: [
+          { keyId: 200, publicKey: b64(randBytes(32)) },
+          { keyId: 201, publicKey: b64(randBytes(32)) },
+        ],
+      });
+
+      expect(res.status).toBe(200);
+      const body = await res.json();
+      expect(body.remaining).toBe(3); // 1 original + 2 new
+    });
+  });
+
+  // ─── Delete ────────────────────────────────────────────────
+
+  describe('DELETE /v1/keys/:address', () => {
+    test('removes all keys for an address', async () => {
+      await req('POST', '/v1/keys/register', {
+        address: 'bob',
+        identitySigningKey: b64(randBytes(32)),
+        identityDHKey: b64(randBytes(32)),
+        signedPreKey: { keyId: 1, publicKey: b64(randBytes(32)), signature: b64(randBytes(64)) },
+        oneTimePreKeys: [{ keyId: 100, publicKey: b64(randBytes(32)) }],
+      });
+
+      const delRes = await req('DELETE', '/v1/keys/bob');
+      expect(delRes.status).toBe(200);
+
+      // Should be gone
+      const bundleRes = await req('GET', '/v1/keys/bundle/bob');
+      expect(bundleRes.status).toBe(404);
+
+      const countRes = await req('GET', '/v1/keys/count/bob');
+      expect((await countRes.json()).count).toBe(0);
+    });
+  });
+
+  // ─── Multiple Addresses ────────────────────────────────────
+
+  describe('multi-address isolation', () => {
+    test('different addresses are independent', async () => {
+      for (const addr of ['alice', 'bob', 'charlie']) {
+        await req('POST', '/v1/keys/register', {
+          address: addr,
+          identitySigningKey: b64(randBytes(32)),
+          identityDHKey: b64(randBytes(32)),
+          signedPreKey: { keyId: 1, publicKey: b64(randBytes(32)), signature: b64(randBytes(64)) },
+          oneTimePreKeys: [{ keyId: 1, publicKey: b64(randBytes(32)) }],
+        });
+      }
+
+      // Delete bob, others remain
+      await req('DELETE', '/v1/keys/bob');
+
+      expect((await req('GET', '/v1/keys/bundle/alice')).status).toBe(200);
+      expect((await req('GET', '/v1/keys/bundle/bob')).status).toBe(404);
+      expect((await req('GET', '/v1/keys/bundle/charlie')).status).toBe(200);
+    });
+  });
+});
diff --git a/packages/shade-server/tsconfig.json b/packages/shade-server/tsconfig.json
new file mode 100644
index 0000000..a086b14
--- /dev/null
+++ b/packages/shade-server/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src"
+  },
+  "include": ["src"]
+}