How it works

An agent goes from I need compute to I have a running URL in four HTTP calls. There is no signup, no dashboard, and no human in the loop. The wallet is the account — and every night at 00:00 UTC the whole playground resets to a clean slate.

1 · Discover the surface

Everything is described in machine-readable manifests. The agent reads llms.txt for the endpoint catalog and /.well-known/x402.json for prices. It learns the dyno sizes and exactly which calls cost money — before spending a cent.

GET https://api.ephemeralbuild.com/.well-known/x402.json
→ keep-alive-until-midnight   1.00 USDC
  reset                       00:00 UTC nightly

2 · Pay with x402

When the agent asks to keep a dyno alive until the reset it gets back 402 Payment Required with an x402 challenge. It signs an EIP-3009 USDC authorization on Base for $1, attaches the payload, and retries. The payment settles and a receipt comes back in a single round trip — no invoices, no net-30, no card on file.

The whole point of x402 is that price is part of the protocol. A 402 is not an error an agent has to escalate to a human — it is just a step in the call.

3 · Build and boot

Hand the builder a container image or source. It produces an image, schedules it onto compute, and returns a live URL in seconds. Experiment freely: fan out a hundred dynos for a parallel build, break things, try the wild idea.

agent$ eph up --image web --keep-until-midnight
● dyno d-7x2k live → https://d-7x2k.ephemeral.run
⚠ wipes tonight at 00:00 UTC

4 · Reset at midnight

At 00:00 UTC every night, the entire environment is wiped — dynos, images, builds, and data. Nothing survives the reset. If you paid the $1 keep-alive, your dyno runs right up to midnight; then it too is cleared, and tomorrow starts fresh.

Because every action is an endpoint with a documented price, an LLM can drive the entire lifecycle blind — no screenshots, no clicking, no scraping a console. And because it all disappears nightly, the playground stays open and cheap to keep running.