`Missing API Key`

Resend · GET /domains · HTTP 401 missing_api_key

Status: ✅ verified:server:prod · first seen 2026-10-31 · last confirmed 2026-10-31 · 1 confirmation from 1 vantage

A request without an API key returns HTTP 401 with the flat body {statusCode: 401, name: "missing_api_key", message: "Missing API Key"}: the error code is in name.

What to do

Send header Authorization = the account setting bearer_api_key.

Example

What probe af:resend:probe:no-key sends (prod) and what it checks in the answer.

GET https://api.resend.com/domains

Response (only what the probe asserts; other fields omitted):

HTTP 401

{
  "statusCode": 401,
  "name": "missing_api_key",
  "message": "Missing API Key"
}

In your code

When an SDK receives this response:

SDK	Raises	Check
Python `resend`	`resend.exceptions.MissingApiKeyError`	`e.code == 401` · `e.error_type == "missing_api_key"`
Node `resend`	returns `{ data: null, error }`	`error.statusCode === 401` · `error.name === "missing_api_key"`

Read from the SDK source: resend 2.50.1: resend/request.py Request.perform, resend/exceptions.py ERRORS; resend 6.37.0: dist/index.cjs Resend.fetchRequest.

Fix 1:

headers["Authorization"] = YOUR_BEARER_API_KEY

Dimensions

env: prod · plan: any · region: any · account_state: anonymous

Evidence

Probe af:resend:probe:no-key (declarative, source)

Observations: none from reporters yet.

Related errors

Missing API Key · GET /emails/{email_id} · HTTP 401 missing_api_key
API key is invalid · GET /domains · HTTP 400 validation_error

Machine access

Match signature (what check() matches): missing api key

curl -s https://apifacts.dev/v0/check \
  -H 'content-type: application/json' \
  -d '{"target":{"method":"GET","url":"https://api.resend.com/domains"},"error":{"status":401,"body_excerpt":"missing api key"}}'

YAML: facts/resend/missing-api-key-401.yaml

Data: CC BY 4.0 · apifacts registry · This page is generated; edit the YAML, not the page.