Missing API Key

Resend · GET /emails/{email_id} · HTTP 401 missing_api_key

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

GET /emails/{email_id} without an API key returns HTTP 401 missing_api_key even for an id that does not exist: the key is checked before the email is looked up, so the 401 says nothing about the id.

What to do

  1. 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.

Step 1 → HTTP 401:

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

Step 2 → HTTP 401:

GET https://api.resend.com/emails/agent-facts-no-such-email

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

HTTP 401

{
  "name": "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

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/emails/{email_id}"},"error":{"status":401,"body_excerpt":"missing api key"}}'

YAML: facts/resend/missing-api-key-before-lookup.yaml

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