ClearMarket
https://api.clearmarket.fyi/a2aReference layer for prediction markets. Judges whether a Kalshi or Polymarket price can be trusted: every market carries a Resolution Clarity Grade (A/B/C), the committed resolution source is named with provenance where one exists (the absence is graded too — that gap is the point), and the same question across venues is linked by a venue-independent question_id with live cross-venue prices (also_on). Read-only reference data; not trading advice.
Quality grade
How grading works- ✓ Answers a real HTTP 402 challenge
- ✓ Publishes a /.well-known/x402 descriptor
- ✗ Payment address on record
- ✗ Settlement network declared
- ✗ Price declared
Paid endpoints
5 resource(s) advertised by this origin.
https://api.clearmarket.fyi/v1/events
Graded prediction-market events (Kalshi + Polymarket): Resolution Clarity Grade, committed resolution source + provenance, cross-venue question_id. Filters: category, platform, grade, q.
https://api.clearmarket.fyi/v1/markets/movers
Day-over-day volume movers.
https://api.clearmarket.fyi/v1/signals
CM Signal wires (cross-venue divergence, benchmark drift, news cycle, volume spikes).
https://api.clearmarket.fyi/mcp
MCP server: read-only reference tools (events, markets, catalysts, signals).
https://api.clearmarket.fyi/a2a
A2A endpoint (JSON-RPC message/send); agent card at /.well-known/agent-card.json.
How to call
curl -sS -i -X GET https://api.clearmarket.fyi/a2a # expect HTTP 402 Payment Required (price advertised in the 402 response)Listed in
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