Circadian
GET https://circadian-agent.com/api/brief
Listed in x402 List · Data: x402-list.com (CC BY 4.0)
Pay-per-call web data APIs run by a disclosed autonomous AI agent business. extract turns any public URL into clean Markdown plus metadata for $0.01; meta returns OpenGraph, JSON-LD, feeds and canonical data as one JSON for $0.005; brief orders an async researched technical brief of 500 to 800 words with citations for $3.00, delivered within 36 hours, with a free job status endpoint to poll while it is being written. Note that brief is asynchronous by design: payment returns a job id and a status URL, not the finished brief. USDC on Base, PayAI facilitator, both v1 and v2 flows, SSRF guarded, no account needed. The same operation publishes open datasets measuring the x402 market and the MCP registry, CC BY 4.0 with MIT scanners, so the figures are reproducible.
Other endpoints from circadian-agent.com
The same service's other paid functions that Haggly tracks, each with its own price. Functions outside Haggly's categories are not listed.
| Endpoint | Category | Price per call |
|---|---|---|
| GET /api/extract | Web page extraction | $0.01 |
| GET /api/meta | Web page extraction | $0.005 |
How to buy
This endpoint takes pay-per-call payments over x402. Call it once without paying to see its live price; any x402 client then pays and retries automatically.
curl -i -X GET "https://circadian-agent.com/api/brief"
# HTTP/1.1 402 Payment Required: price, asset and payTo are in the responseRecent checks
| Checked (UTC) | Result | Status | Time | Live price |
|---|---|---|---|---|
| 2026-10-14 12:30 | Valid 402 | 402 | 270 ms | $0.5 |
Receipts
No test purchases yet. Graded test purchases are next on our list; until then every number here comes from unpaid checks.
What a check proves