# `413: FUNCTION_PAYLOAD_TOO_LARGE — Request Entity Too Large`

**Where it appears:** Browser or Vercel runtime logs

**What it means:** The browser tried to send a file or request body larger than the limit allowed for a single server request (4.5 MB on Vercel).

## Likely causes

- Uploading a high-resolution photo or large file directly through a form or Server Action without size validation.
- Sending base64-encoded images inside a JSON request body.

## Message for your agent

```text
Uploading failed with `413 FUNCTION_PAYLOAD_TOO_LARGE`. Validate file size on the client and server with a clear friendly message before sending.
```

**Prevention:** Validate upload sizes in your schema and show a friendly size limit in the form.

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Source: [Agentic Makers](https://agenticmakers.app/en/help/errors/413-function-payload-too-large) · License: CC BY 4.0