413 Payload Too Large

Meaning & Description

Common Causes

• File uploads exceeding the maximum permitted size configured in Nginx/Apache.
• Framework-level body parser limits (e.g., Express.js `body-parser` default is usually 100kb).
• Ingress controllers or API gateways blocking large payloads before they reach the application.

How to fix a 413 error

1. Check your reverse proxy or web server settings (e.g., `client_max_body_size` in Nginx).
2. Check your application framework's body parser configuration (e.g., Express `express.json({ limit: "50mb" })`).
3. If the limit is intentional, compress the payload on the client or implement chunked/resumable file uploads.
4. Check if a `Retry-After` header is present in the response.

Browser & SEO Behaviour

Code Examples

HTTP/1.1 413 Payload Too Large
Connection: close
Content-Type: application/json

{
  "error": "File exceeds maximum allowed size of 5MB."
}

const express = require("express");
const app = express();

// Set a payload limit; Express returns 413 automatically if exceeded
app.use(express.json({ limit: "5mb" }));

app.post("/data", (req, res) => {
  res.send("Payload accepted");
});

from fastapi import FastAPI, Request, HTTPException

app = FastAPI()
MAX_SIZE = 5 * 1024 * 1024  # 5MB

@app.post("/upload")
async def upload(request: Request):
    body = await request.body()
    if len(body) > MAX_SIZE:
        raise HTTPException(status_code=413, detail="Payload Too Large")
    return {"message": "Success"}

func handler(w http.ResponseWriter, r *http.Request) {
    // Limit body to 5MB. If exceeded, returns 413 automatically by some middlewares or manual check
    r.Body = http.MaxBytesReader(w, r.Body, 5<<20)
    err := r.ParseForm()
    if err != nil {
        http.Error(w, "Payload Too Large", http.StatusRequestEntityTooLarge)
        return
    }
    w.WriteHeader(http.StatusOK)
}

[HttpPost("upload")]
[RequestSizeLimit(5_000_000)] // 5MB limit
public IActionResult Upload()
{
    return Ok();
}

# Attempting to send a massive file
curl -X POST -F "file=@huge_video.mp4" https://api.example.com/upload

Raw HTTP Response Example

HTTP/1.1 413 Payload Too Large
Date: Wed, 21 Oct 2026 07:28:00 GMT
Connection: close
Content-Type: application/json

{"error": "Max upload size is 10MB"}

Real-world Examples

Frequently Asked Questions

Developer Tips

• Implement client-side validation to check file sizes before initiating an upload. This saves bandwidth and provides a faster, better user experience.
• For very large uploads, consider implementing a chunked upload mechanism (e.g., using Tus protocol) or presigned URLs directly to cloud storage (like S3) to bypass your application server.
• Always ensure your reverse proxy (like Nginx), API gateway, and application framework have their max body size limits aligned so the error is caught at the earliest possible stage.

Interview Questions

These are questions you might face in a backend or API design interview that touch on HTTP 413.