VerifyAPI
officialFact-check any claim with live web sources. Ed25519-signed receipts. Catches hallucinations. One MCP tool: verify_claim. $0.02 per check, free trial.
What can you do with VerifyAPI MCP?
- Verify a factual claim — Ask your AI to check a claim and get a
supported,refuted, orinsufficient_evidenceverdict with a verbatim source quote viaverify_claim. - Try before paying — Have your assistant test a claim using the free
/v1/verify/trialendpoint, no API key or account required. - Create an API account — Instruct your AI to sign up for an API key instantly via
POST /v1/accounts, with no email or card needed. - Top up your balance — Ask your assistant to add credit using preset tiers ($10–$1,000) or a custom amount via the
/v1/balance/topupendpoints.
Documentation
Verify a claim.Get a verdict backed by a real quote.
POST one factual claim. We search the live web, extract the sources, adjudicate, and return supported / refuted / insufficient_evidence — with the exact verbatim passage the verdict came from. $0.02 per verified claim, billed only on success.
curl https://api.verify-api.dev/v1/verify \
-H "Authorization: Bearer csk_live_..." \
-H "Idempotency-Key: 018f4c8a-1234-4321-abcd-e3f6a7b8c9d0" \
-d '{"claim":"The iPhone 15 launched on September 22, 2023."}'
{
"verdict": "supported",
"confidence": 0.97,
"source_url": "https://www.apple.com/newsroom/2023/09/...",
"published_date": "2023-09-12",
"exact_quote": "iPhone 15 and iPhone 15 Plus will be available … on Friday, September 22.",
"cache": "miss",
"billed_usd": 0.02
}
Try it before you sign up
No account, no key, no card. POST /v1/verify/trial from anywhere, rate-limited per IP. Same verdict shape, same signed receipt.
curl -X POST https://api.verify-api.dev/v1/verify/trial \
-H "Content-Type: application/json" \
-d '{"claim":"The iPhone 15 launched on September 22, 2023."}'
Verdicts, not documents
Everyone else returns pages. We return a decision — with a quote you can show your user.
Billed only on success
insufficient_evidence, out_of_scope, and malformed are free. Our incentives are aligned with yours.
Verbatim-quote gate
Every verdict includes text that appears character-for-character in the cited source. No hallucinated citations, by construction.
Works everywhere agents live
Native REST for programmatic callers, MCP server for Claude Desktop, Cursor, Windsurf, ChatGPT Desktop, and any MCP-capable host.
One line of pricing.
$0.02 per verified claim
- Prepaid balance, top up any amount ≥ $5
- Free:
insufficient_evidence,out_of_scope,malformed - Semantic cache hits still count as billable if we return a verdict
- No seats, no monthly minimum, no rate-limit tiers Start with $5
Drop-in for MCP clients.
Add one block to your MCP config and the model gets a verify_claim tool alongside its other tools. Works with Claude Desktop, Cursor, Windsurf, VS Code Copilot agent mode, and any other MCP-capable host.
{
"mcpServers": {
"verifyapi": {
"command": "npx",
"args": ["-y", "@verify-api/mcp"],
"env": { "VERIFYAPI_API_KEY": "csk_live_..." }
}
}
}
Get an API key. Instantly.
One POST, no email, no waitlist, no card. Free trial calls with no key at /v1/verify/trial, or grab a key here and top up when you're ready. Same endpoint, whether you're an agent, a script, or a human.
curl -X POST https://api.verify-api.dev/v1/accounts \
-H "Content-Type: application/json" \
-d '{"source":"curl"}'
Response includes api_key (shown once — save it). Balance starts at $0 — top up any amount, or use the free trial endpoint first.
Limit: 3 signups per IP per day. If you hit that, wait 24h or use /v1/verify/trial in the meantime.
Top up your balance
Add credit via Stripe Checkout — pay-as-you-go, no minimums past $1, no expiry. Cache hits within your account are always free.
One-click preset ($10 / $50 / $200 / $1,000)
curl -X POST https://api.verify-api.dev/v1/balance/topup/preset \
-H "Authorization: Bearer csk_live_..." \
-H "Content-Type: application/json" \
-d '{
"tier": "50",
"success_url": "https://your-app.example/topup/done",
"cancel_url": "https://your-app.example/topup/cancel"
}'
Returns {checkout_url, session_id}. Redirect the user to checkout_url. Valid tier values are the strings "10", "50", "200", "1000" (dollar amounts).
curl -X POST https://api.verify-api.dev/v1/balance/topup \
-H "Authorization: Bearer csk_live_..." \
-H "Content-Type: application/json" \
-d '{
"amount_usd": 25,
"success_url": "https://your-app.example/topup/done",
"cancel_url": "https://your-app.example/topup/cancel"
}'
All three fields are required. amount_usd must be a positive number ≥ the server minimum (currently $1).
For long-running agents, enable auto-refill in the dashboard — save a card once, never get stuck mid-task on an empty balance.