402cron — cron for AI agents, paid per delivery
402cron calls your https endpoint on a cron schedule, signs every request, and retries what fails.
An agent can set it up on its own: no account, no card, no human in the loop. Payment is
x402 — USDC on Base — and the only identity is the wallet that paid.
This repository holds documentation and runnable examples. The service runs at
https://402cron.com; its source code is not published.
Links
Further reading
Pricing
| Pack | Price | Deliveries | Per delivery |
|---|
trial | $0.02 | 20 | $0.001 |
starter | $2 | 4,000 | $0.0005 |
month | $25 | 50,000 | $0.0005 |
The balance counts deliveries, not money, and never expires. Each delivery attempt uses one
credit, so a failing delivery costs at most three. Current prices: https://402cron.com/api/pricing.
How it works
- Buy.
GET https://402cron.com/buy/trial answers 402 with the price in the
PAYMENT-REQUIRED header. Pay with any x402 client. The receipt carries your management
token, shown once.
- Register.
POST /api/destinations with {"url": "https://your.host/hook"} returns the
destination id and its signing secret, shown once.
- Verify. Call
POST /api/destinations/{id}/verify. We POST a challenge to your URL and your
endpoint echoes it back. The permission then covers that path and everything below it.
- Schedule.
POST /api/tasks with {"name", "url", "cron", "body"}. The response shows the
next three runs.
Management calls take Authorization: Bearer <token>. Lost the token? Buy again from the same
wallet with ?rotate=1; the old token stops working.
What your endpoint receives
Three kinds of requests arrive at the same URL. X-402cron-Event tells them apart:
X-402cron-Event | When | Signed | Your endpoint should |
|---|
verify | once, when you call /verify | no | answer with the X-402cron-Challenge value as the body, within 5 s |
delivery | on schedule, on retries, and when you call /run | yes | check the signature and answer 2xx within 2 s |
task_paused | once, when a task pauses | yes | read reasonCode, fix the cause, POST the resume URL |
The signature is X-402cron-Signature: sha256=<hex>, an HMAC-SHA256 keyed with your signing
secret over the bytes of:
{X-402cron-Timestamp}\n{X-402cron-Delivery-Id}\n{X-402cron-Attempt}\n{METHOD}\n{path+query}\n{raw body}
The event label is not signed: branch on it, but trust what the signature covers. Delivery is
at least once — the same X-402cron-Delivery-Id can arrive twice, so treat a repeat as
already handled. Deliveries also carry X-402cron-Task-Id and X-402cron-Deliveries-Left.
Retries and pausing
- A timeout or an unreachable host is retried: up to 3 attempts, 60 s and 120 s apart.
- A
4xx or 5xx is your server's answer, so it is not retried.
- 3 failed attempts, 20 refusals in a row, or 10 server errors in a row pause the task. You get one
task_paused notice; resuming is one call.
Limits
cron: 5 fields, always UTC, one minute at the finest. Names (MON-FRI, JAN) and macros
(@daily, @hourly, …) work; anything unsupported is refused with a code that says why.- Destinations must be
https://.
- Body up to 64 KB, custom headers up to 8 KB.
All limits: https://402cron.com/docs?section=limits
Examples
| Folder | What it is | Run |
|---|
receiver/node | a destination endpoint, no dependencies | SECRET_402CRON=… node server.mjs |
receiver/python | the same, standard library only | SECRET_402CRON=… python server.py |
client | buy a trial with x402, register, verify, schedule | npm install, then DRY_RUN=1 node buy-and-schedule.mjs |
Both receivers answer the challenge, verify signatures, drop duplicate deliveries and log pause
notices. The client reads the price from the PAYMENT-REQUIRED header like any standard x402
client, caps what it may spend (MAX_USD, default $0.05), and with DRY_RUN=1 signs without
paying anything. On Windows PowerShell, set variables with $env:SECRET_402CRON="…" first.
Use it from an MCP client
Claude Code:
claude mcp add --transport http 402cron https://402cron.com/mcp --header "Authorization: Bearer <token>"
Other clients: add a remote (streamable HTTP) server at https://402cron.com/mcp with the same
header. get_pricing, get_docs and get_service_status work without a token. There is no
purchase tool on purpose: pay over plain HTTP, because a signed payment should not travel through a
model's context.
Guarantee
We guarantee that we tried to deliver your task — not what someone else's server does with it.
Full terms: https://402cron.com/terms
License
The examples in this repository are MIT-licensed — see LICENSE.