Send evidence
Submit a factual claim, topic, or public source URL using JSON.
Research verification infrastructure
Pay only when your agent needs an answer.
Verify citations, extract evidence, compare claims, score sources, and build research briefs for $0.01–$0.10 per request. No account. No subscription. USDC settlement over x402 on Base Mainnet.
Every paid route first returns HTTP 402 with exact payment requirements. x402 client libraries can authorize payment and retry automatically.
12live paid APIs
$0.01lowest entry price
BaseMainnet USDC
● ● ●
# Test the live endpoint - no wallet or payment
curl -i -X POST https://apexibis.com/verify-citation -H "Content-Type: application/json" --data '{"claim":"The United States declared war on Japan on December 8, 1941.","sourceUrl":"https://www.archives.gov/milestone-documents/joint-address-to-congress-declaration-of-war-against-japan"}'
# Response: HTTP 402 Payment Required
# Inspect the PAYMENT-REQUIRED header for the price,
# network and receiving wallet before you sign.
# Complete a paid call with an x402 client.
# Step-by-step: https://apexibis.com/docs#quickstartWhat buyers get
One purchase. One exact price. One structured result.
Pay automatically
The client handles the 402 challenge, signs the exact USDC payment, and retries.
Use the answer
Receive machine-readable JSON for your agent, pipeline, application, or research workflow.
Live catalog
Twelve specialized research tools.
| Product | Endpoint | Price |
|---|---|---|
| Citation verification | POST /verify-citation |
$0.01 |
| Evidence extraction | POST /extract-evidence |
$0.02 |
| Claim comparison | POST /compare-claims |
$0.03 |
| Source credibility | POST /score-source |
$0.03 |
| Research brief | POST /research-brief |
$0.10 |
| Fact check | POST /fact-check |
$0.04 |
| Timeline extraction | POST /extract-timeline |
$0.04 |
| Conflict detection | POST /detect-conflicts |
$0.05 |
| Statistical claim check | POST /check-statistics |
$0.05 |
| Research questions | POST /generate-research-questions |
$0.03 |
| Company intelligence | POST /company-intelligence |
$0.08 |
| Document change analysis | POST /document-change |
$0.06 |
For AI agents
Use the OpenAPI document, machine manifest, Bazaar discovery metadata, or the included MCP bridge.
For developers
Use the automatic-paying Node buyer examples or call the REST endpoints from any x402-compatible client.
For research systems
Insert verification, evidence extraction, and source-quality checks directly into RAG and due-diligence pipelines.
Fastest integration path
Start with the one-cent citation verifier.
Run the buyer example, complete one real payment, inspect the structured result, then move the endpoint into your application.