Bun guide

Protect a Bun HTTP server with API keys. Bun.serve has one fetch handler, so you call a verify helper at the top of it, and keys.verifyKey decides whether the request goes on.

You need a root key with the permissions listed on this page. Create one in the dashboard under Settings > Root Keys, and pass it as Authorization: Bearer <root key>. See Permission reference for every permission.

Create a root key and a keyspace

In the dashboard, go to Settings > Root Keys and create a root key with api.*.create_api, api.*.create_key, and api.*.verify_key. Put it in your server’s UNKEY_ROOT_KEY environment variable. Never send it to a browser or mobile app.Then create a keyspace, which holds your keys. Use Keyspaces (APIs) in the dashboard, or apis.createApi:

create a keyspace

curl -X POST https://api.unkey.com/v2/apis.createApi \
  -H "Authorization: Bearer $UNKEY_ROOT_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "name": "my-api" }'

Keep the data.apiId from the response. You need it to create keys. See Root keys for more on root keys.

Install the SDK

@unkey/api (version ) runs unchanged on Bun.

bun add @unkey/api

Create a key for a user

Create a key from your backend when a user signs up or asks for one. externalId links the key to the user, so verification tells you who’s calling. meta comes back on every verification. You get data.key only once: show it to the user and store only data.keyId.

curl -X POST https://api.unkey.com/v2/keys.createKey \
  -H "Authorization: Bearer $UNKEY_ROOT_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "apiId": "api_...", "prefix": "sk_live", "externalId": "user_123", "meta": { "plan": "free" } }'

import { Unkey } from "@unkey/api";

const unkey = new Unkey({ rootKey: process.env.UNKEY_ROOT_KEY ?? "" });

const created = await unkey.keys.createKey({
  apiId: process.env.UNKEY_API_ID ?? "",
  prefix: "sk_live",
  externalId: "user_123",
  meta: { plan: "free" },
});
// created.data.key is the plaintext, created.data.keyId the handle you keep

Every field is described in Creating keys.

Verify the key in the fetch handler

The helper returns either the verification data or a Response to send back. Its optional second argument is a permission query, for routes that need more than a valid key. You can read the root key from Bun.env or process.env.

server.ts

import { Unkey } from "@unkey/api";
import * as errors from "@unkey/api/models/errors";

const unkey = new Unkey({ rootKey: Bun.env.UNKEY_ROOT_KEY ?? "" });

async function authenticate(req: Request, permissions?: string) {
  const auth = req.headers.get("authorization") ?? "";
  const key = auth.startsWith("Bearer ") ? auth.slice("Bearer ".length) : "";
  if (!key) {
    return Response.json({ error: "missing API key" }, { status: 401 });
  }
  try {
    const result = await unkey.keys.verifyKey({ key, permissions });
    if (!result.data.valid) {
      return Response.json({ error: result.data.code }, { status: statusFor(result.data.code) });
    }
    return result.data;
  } catch (err) {
    if (err instanceof errors.UnkeyError) {
      console.error("unkey", err.statusCode, err.message);
    }
    return Response.json({ error: "authentication unavailable" }, { status: 503 });
  }
}

function statusFor(code: string): number {
  switch (code) {
    case "RATE_LIMITED":
      return 429;
    case "USAGE_EXCEEDED":
      return 402;
    case "FORBIDDEN":
    case "INSUFFICIENT_PERMISSIONS":
      return 403;
    default:
      return 401;
  }
}

Bun.serve({
  port: 3000,
  async fetch(req) {
    const url = new URL(req.url);
    if (url.pathname === "/items") {
      const auth = await authenticate(req);
      if (auth instanceof Response) return auth;
      return Response.json({ items: [], owner: auth.identity?.externalId });
    }
    if (url.pathname === "/exports") {
      const auth = await authenticate(req, "exports.create");
      if (auth instanceof Response) return auth;
      return Response.json({ started: true });
    }
    return new Response("not found", { status: 404 });
  },
});

bun run server.ts
curl http://localhost:3000/items -H "Authorization: Bearer sk_live_..."

Handle the outcome codes

keys.verifyKey returns HTTP 200 for every outcome. Check data.valid, then data.code for the reason, and return the matching status from your API:

`data.code`	Meaning	Return
`VALID`	Every check passed.	continue
`NOT_FOUND`	No such key, or your root key may not verify this keyspace.	401
`DISABLED`	The key was disabled.	401
`EXPIRED`	The key’s expiry passed.	401
`FORBIDDEN`	Client IP not on the keyspace allow list, or the workspace is disabled.	403
`INSUFFICIENT_PERMISSIONS`	The `permissions` query was not satisfied.	403
`RATE_LIMITED`	A on the key or its identity was exceeded.	429
`USAGE_EXCEEDED`	The key has no credits left.	402 or 429

Remaining credits are in data.credits, and each checked rate limit is in data.ratelimits with remaining and reset. The call only fails with an HTTP error (which the SDKs throw) when the call itself is wrong, such as a bad root key or a malformed body. See Verifying keys for every field.

Next steps

Verifying keys

Every request field, the order of checks, and every response field.

Credits and refill

Meter usage per key and refill balances on a schedule.

Cookbook

Copy-ready recipes for rate limits, billing, and subscription tiers.

Get started

Framework guides

Keyspaces

Keys

Rate limiting

Identities

Authorization

Analytics

Audit logs

Developer portal

Security

Cookbook

Create a root key and a keyspace

Install the SDK

Create a key for a user

Verify the key in the fetch handler

Handle the outcome codes

Next steps

Verifying keys

Credits and refill

Cookbook