API + MCP

Build on evidence.

Base URL: https://fluxproof.tryneverclosed.com. Send API keys as Authorization: Bearer fp_…. MCP endpoint: https://fluxproof.tryneverclosed.com/mcp.

Free preflight

POST /v1/preflight
{"url":"https://example.com"}

Get a key

POST /v1/keys/free
(MCP: fluxproof_get_free_key)

Free: one page, checked daily for 30 days, no card. Paid: the $9 Monitor Pass from Pricing. A key is shown once; store it like a password. Lost a paid key? Email bryan@tryneverclosed.com with your Stripe receipt.

Create monitor

POST /v1/monitors
Authorization: Bearer fp_…
{"url":"https://example.com/pricing","watch_terms":["price"]}

Read changes

GET /v1/monitors/{id}/changes
Authorization: Bearer fp_…

Evidence plans

Keys from an evidence plan add timestamped captures and proof packets. A capture is saved at the first check, at every change, and once a day while a page's declared price stays below its floor.

Price floor

POST /v1/monitors
{"url":"https://store.example/p","price_floor":49.99}

PATCH /v1/monitors/{id}
{"price_floor":44.99}

Many pages

POST /v1/monitors/bulk
{"pages":[{"url":"https://...","price_floor":49.99}]}

Packets

GET /v1/monitors/{id}/captures
GET /v1/captures/{id}/packet
GET /v1/changes/{id}/packet
POST /v1/monitors/{id}/capture

Packets are ZIP files. Signing key: /.well-known/fluxproof-signing-key.pem.

Renew a 30-day pass

POST /v1/plan/renew

Returns a Stripe Checkout URL; paying it adds 30 days to the same key (also after it expired) and resets its check allowance.

Cancel a monthly plan

POST /v1/subscription/cancel

No further charges; access lasts to the end of the paid month. People can also use /plan/cancel or the link in any FluxProof email.

Switch a pass to monthly

POST /v1/plan/renew
{"monthly":true}

Only when /health shows billing card_monthly. Returns a Stripe Checkout URL; the buyer agrees there to a charge every 30 days until canceled.

Agent discovery

GET /.well-known/agent-commerce.json
GET /.well-known/mcp/server-card.json
POST /mcp

Payment authority always belongs to the buyer. Offer discovery and free preflight never charge.

Coverage boundary

FluxProof fetches public HTTP or HTTPS text, HTML, JSON, and XML responses up to 3 MB. It does not sign in, solve bot challenges, or run a browser for JavaScript-only and authenticated pages.