Functions

One handler, one trigger. No container, no scaling config. The mesh handles cold start, hot path, scale-out, and tear-down. Billed in joules per invocation — an idle function literally costs nothing.

A function

// hello.js — exported as the default handler
export default async function (req) {
  const body = await req.json();
  return new Response(JSON.stringify({ hello: body.name }), {
    headers: { "content-type": "application/json" },
  });
}

Deploying

invisible fn deploy hello.js   --route /hello   --runtime node-22   --memory 256MB

Live in a few seconds at https://<account>.fn.greenjoules.cloud/hello. Or attach a custom domain via the route block.

Runtimes

Triggers

• HTTP — the default; one function per route
• Cron — --cron "0 * * * *"
• Object Store events — --on bucket/jc-uploads/object-created
• Queue — --on queue/jobs

Energy & billing

Cold start joules + execution joules + waiting-on-IO joules (which are tiny, because the runtime is suspended). Each invocation produces a receipt with energy.cold_start_j and energy.execution_j as separate fields so you can see what your function actually costs.

Limits at launch

• 30s max execution per HTTP invocation; 15min for cron / event triggers
• Memory: 128 MB – 4 GB
• Up to 1000 functions per account
• Per-function concurrency cap configurable; defaults to 1000 simultaneous

Compared to Lambda / Cloud Functions / Cloudflare Workers

Joule-billed instead of GB-second-billed, no per-region deploys (one deploy, the mesh places it), and the cold-start cost shows up on the receipt instead of being invisible. For request-heavy edge work, very competitive on price. For long-running batch work, prefer Compute.