Size Limitation for Server Actions in Next.js 14

[cornelvonwyl]

https://nextjs.org/docs/app/api-reference/functions/server-actions#size-limitation

How can I increase the size limit for Server Actions in Next.js 14? Since Server Actions are stable, the documentation is outdated.

[amplicity]

ditto -- where is this documentation?

[SidKH]

https://nextjs.org/docs/app/api-reference/next-config-js/serverActions#bodysizelimit

[amplicity]

In next 14, server actions are no longer experimental. Specifying the options stated in those docs does nothing. Output from the server on start reads:

 ⚠  Unrecognized key(s) in object: 'serverActions' at "experimental"
 ⚠ See more info here: https://nextjs.org/docs/messages/invalid-next-config
 ⚠ Server Actions are available by default now, `experimental.serverActions` option can be safely removed.

I can confirm that specifying the body limit within the options does not work as stated in documentation. Documentation is outdated and broken for next 14.

[SidKH]

Enabling server actions via experimental.serverActions = true should trigger the warning.
However, changing the bodySizeLimit should work fine.

CleanShot.2024-01-21.at.21.07.28.mp4

[amplicity]

I tried your exact settings and get

However, it does appear to work with some preliminary testing. My next.config is below. Note that I'm on 14.0.1, vs your 14.0.4

/** @type {import('next').NextConfig} */
const { version } = require("./package.json");
module.exports = {
  env: {
    version,
  },
  reactStrictMode: true,
  experimental: {
    serverActions: {
      bodySizeLimit:"100mb",
    },
  },
  images: {
    remotePatterns: [
      {
        protocol: "https",
        hostname: "**",
      },
    ],
  },
};

[abundiko]

https://nextjs.org/docs/app/api-reference/next-config-js/serverActions#bodysizelimit

this doesn't work
currently using next 14.2.2

adding the config specified on the docs does not seem to have any effect.
My walkaround was to upload the files on the client side

[DaveCole]

Running into a similar issue - it seems that regardless of whether serverActions: { bodySizeLimit: ... } is put in experimental or in the main config body for 14.1.4 it doesn't seem to matter. I have a page (using the old pages folder method) that attempts to do a POST via a form with a field that exceeds 1MB in size, and I get this error (the getServerSideProps code doesn't even execute - I tried to throw an error to catch it and it doesn't get reached):

web-1       |  ⨯ Error: {"errors":[{"name":"FIELD_SIZE_EXCEEDED","message":"field \"body\" exceeds 0B"}]}
web-1       |     at getProperError (/app/node_modules/next/dist/lib/is-error.js:41:12)
web-1       |     at DevServer.renderToResponseImpl (/app/node_modules/next/dist/server/base-server.js:1904:53)
web-1       |     at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
web-1       |     at async DevServer.pipeImpl (/app/node_modules/next/dist/server/base-server.js:895:25)
web-1       |     at async NextNodeServer.handleCatchallRenderRequest (/app/node_modules/next/dist/server/next-server.js:269:17)
web-1       |     at async DevServer.handleRequestImpl (/app/node_modules/next/dist/server/base-server.js:791:17)
web-1       |     at async /app/node_modules/next/dist/server/dev/next-dev-server.js:331:20
web-1       |     at async Span.traceAsyncFn (/app/node_modules/next/dist/trace/trace.js:151:20)
web-1       |     at async DevServer.handleRequest (/app/node_modules/next/dist/server/dev/next-dev-server.js:328:24)
web-1       |     at async invokeRender (/app/node_modules/next/dist/server/lib/router-server.js:174:21)
web-1       |     at async handleRequest (/app/node_modules/next/dist/server/lib/router-server.js:353:24)
web-1       |     at async requestHandlerImpl (/app/node_modules/next/dist/server/lib/router-server.js:377:13)
web-1       |     at async Server.requestListener (/app/node_modules/next/dist/server/lib/start-server.js:140:13) {
web-1       |   page: '/admin/customers/1/dashboards/1/edit'
web-1       | }

[amplicity]

At this point, I'm convinced that there is not an official way to increase serverActions bodySizeLimit. After testing, I don't believe the limit I've put in place above actually works as expected. I followed the instructions here for 14, which yields an 'incorrect config' error upon application start, and does not seem to work as expected.

Can someone from the nextjs team comment as to whether this is definitively supported or not? If so, we'd really appreciate the documentation being updated to reflect the best practice.

[zdaar]

I have the same issue. Doc has not been updated, and there seem to be no way to do this.

[DaveCole]

The workaround I came up with in the meantime is to compress the body of the POST before sending it and decompress it on the API side afterwards. For strings, I use lz-string but not sure what's out there for binaries.

[vubui]

How do we flag this to the Next.js team?

I followed the documentation; however, the config seems to have no effect on the body size limit.

[angelpadillar]

This is still an ongoing issue in Next.js 14 had to compress and then decompress in the API route to work around.

[LuisGilGB]

I have a small PoC in v15.0.0-canary.68 to test some transcription issues with Whisper and it looks like the limit of server functions is being applied to server actions when you have the app deployed on Vercel.

Basically my PoC consists in a local video uploader, the file is then sent on a button click to Whisper to get the transcription. Everything happens in the client except the request to OpenAI, which is made from the server (to keep access keys private). First I implemented it defining an API, and when I hit the 4.5MB size limit of the payload of server functions (I'm dealing with videos that usually are up to 10MB), I used a server action instead. Server actions did fine in local environment; but when deployed the app on Vercel I got the FUNCTION_PAYLOAD_TOO_LARGE error again.

Summing it up, these were my findings:

Using a Server action to send a file in a form data payload. Size limit of 25MB in Next Config:

	Local	Vercel Preview
4MB video	Ok	Ok
5MB video	Ok	KO