Pxxl Functions

Pxxl Functions lets a frontend repository expose lightweight HTTP handlers from api/**. Pxxl detects the files, bundles them during the build, and deploys the frontend and functions as one immutable runtime generation. Route activation happens only after the new runtime is healthy, so a deployment cannot combine old functions with new frontend files.

Pxxl Functions is available on staging first. It runs as a warm, gVisor-isolated Node.js workload in your project’s compute pool. Function requests are not billed a second time per invocation.

Create a function

Add a JavaScript or TypeScript file below api/. Each file becomes a route with the same path.

File	Route
`api/index.ts`	`/api`
`api/og.ts`	`/api/og`
`api/users/[id].ts`	`/api/users/:id`
`api/files/[...path].ts`	`/api/files/:path*`

Pxxl bundles up to 64 function files, with up to eight directory levels. Supported extensions are .js, .mjs, .cjs, .ts, .mts, and .cts. Declaration, test, and spec files are ignored.

Use a Vercel-style handler

Existing @vercel/node handlers can normally move without source changes. Type-only imports are removed by the TypeScript bundle.

import type { VercelRequest, VercelResponse } from "@vercel/node";

export default async function handler(req: VercelRequest, res: VercelResponse) {
  const username = req.query.username;
  res.setHeader("Content-Type", "text/html; charset=utf-8");
  res.setHeader("Cache-Control", "public, s-maxage=300");
  return res.status(200).send(`<h1>${username}</h1>`);
}

The response supports status(), send(), json(), redirect(), setHeader(), getHeader(), write(), and end(). The request includes parsed query, cookies, and JSON body values.

Use a Web handler

You can also export a Web API handler that returns a Response.

export async function GET(request: Request) {
  const username = new URL(request.url).searchParams.get("username");
  return Response.json({ username });
}

Named HTTP method exports take precedence over the default export. A default export with two parameters is treated as a Vercel-style handler; a one-parameter export is treated as a Web handler.

Route requests to a function

An internal rewrite can send a public page request to a detected function. The browser keeps the original URL. A pxxl.toml rewrite whose destination is /api or /api/** also explicitly selects the function runtime. This keeps deployment classification deterministic if repository directory discovery is temporarily unavailable; the build still verifies that the referenced handler exists before activating routes.

version = 1

[[rewrites]]
source = "/:slug"
destination = "/api/og?username=:slug"
has_header = { key = "user-agent", regex = "(?i).*(twitterbot|whatsapp|discordbot|googlebot).*" }

[[rewrites]]
source = "/(.*)"
destination = "/spa.html"

You can keep an equivalent vercel.json unchanged when pxxl.toml is absent. Pxxl applies its rewrites to both static and function-enabled deployments. Real asset requests such as /favicon.ico and /assets/app.js win over parameter rewrites.

Cache function responses

Return Cache-Control with s-maxage to cache a successful function response in the warm workload.

res.setHeader("Cache-Control", "public, s-maxage=300");

The cache is bounded to 128 responses by default, caps s-maxage at one hour, and skips responses that are private, use no-store, set cookies, exceed 1 MiB, or return an error. Its key includes the deployment generation, method, rewritten path, and query string. A new deployment therefore starts with a fresh cache automatically.

Limits and safety

Request bodies are limited to 4 MiB by default.
Function builds fail when a TypeScript or JavaScript bundle cannot be produced.
Invalid conditional or /api/** rewrites fail the deployment instead of publishing a partially working release.
Function errors are written to project logs. Callers receive a generic error response without the internal exception message.
Secrets come from project environment variables. Do not store secrets in pxxl.toml or vercel.json.

Function CPU and memory usage appears with the rest of the project runtime usage. Scaling replaces the active generation through the normal zero-downtime route cutover; it does not create a separate function invoice.

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Pxxl Functions

Create a function

Use a Vercel-style handler

Use a Web handler

Route requests to a function

Cache function responses

Limits and safety

​Create a function

​Use a Vercel-style handler

​Use a Web handler

​Route requests to a function

​Cache function responses

​Limits and safety

Create a function

Use a Vercel-style handler

Use a Web handler

Route requests to a function

Cache function responses

Limits and safety