What does 'TooManyRequestsException: Rate Exceeded' mean on Remotion Lambda?

TooManyRequestsException: Rate Exceeded.
ConcurrentInvocationLimitExceeded

What it means

Your AWS account has reached its Lambda concurrency limit.

• Concurrency limit: the maximum number of Lambda functions that can run at the same time, per region per account.
• Burst limit: the maximum increase in concurrency within 10 seconds. It is 1000.

By default the concurrency limit is 1000 functions per region, though in some regions the burst limit is only 500. The surprise is new accounts. According to AWS, some accounts new to Lambda get a very low limit such as 10 when they start. A distributed Remotion render wants many more than that, so it fails straight away, and it looks like Remotion is broken.

Fix: render anyway while you wait for a higher limit

From Remotion 4.0.517 you can set concurrency to 1 to render the whole video on the main function. It is slower than distributed rendering, but it lets you test:

npx remotion lambda render <serve-url> <composition-id> --concurrency=1

import { renderMediaOnLambda } from "@remotion/lambda/client";

await renderMediaOnLambda({
  region: "us-east-1",
  functionName: "remotion-render-bds9aab",
  serveUrl: "https://example.com",
  composition: "MyVideo",
  codec: "h264",
  concurrency: 1,
});

A progress request may briefly use one extra invocation.

You can also use limited distributed rendering by setting concurrency below your limit and leaving room for the launch function, progress requests, other renders and unrelated Lambda functions in the same region. For an account limit of 10, this uses up to eight renderer functions and one launch function, leaving one invocation for progress:

npx remotion lambda render <serve-url> <composition-id> --concurrency=8

Use a lower number if other workloads share the quota.

See your limits and request an increase

npx remotion lambda quotas
npx remotion lambda quotas increase

The first shows your limits. The second requests an increase, and works only for AWS root accounts. For accounts in an organisation, request it in the AWS Service Quotas console instead. If you get a permission error from quotas, repeat the user policy step in Remotion's Lambda setup guide and update your policy file in the AWS console.

Plan for production

Request a quota increase for any production workload that needs higher concurrency, and remember that the number of videos you can render at once is your account limit divided by the functions each render spawns. Rendering several videos concurrently on a limited account can exhaust it quickly. If that arithmetic is the real problem, see whether Remotion fits your use case.

Check it worked

A single small render with --concurrency=1 should complete. Then raise concurrency in steps while watching npx remotion lambda quotas.