Resend · api · fg-0410

Resend returns 429 rate_limit_exceeded when sending a list with Promise.all

429 rate_limit_exceeded: Too many requests. Please limit the number of requests per second.

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

Resend allows 10 requests per second per team with no burst, and every API key on the team shares that pool. Firing one request per recipient in parallel overruns it instantly.

Fix

Use the batch endpoint for up to 100 emails per call, throttle the rest, and on 429 wait for the retry-after header before retrying.

Apply

for (const chunk of chunks(emails, 100)) { await resend.batch.send(chunk); await sleep(150); }

Affects: Resend API, default team limit 10 requests per second as of 2026-10

Sources

• https://resend.com/docs/api-reference/rate-limit
• https://resend.com/docs/knowledge-base/account-quotas-and-limits

claude mcp add --transport http footgun https://getfootgun.com/api/mcp