# SAVER Verifier

> SAVER Verifier is a paid API for AI agents from api.saververify.com, paid per call via x402, $0.2/call, status unknown (last checked 2026-10-11).

Verifies factual claims against authoritative sources and returns a support verdict, evidence, and confidence score

## Facts

- Endpoint: POST https://api.saververify.com/verify?utm_source=zero.xyz
- Price: $0.2/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saver-verifier-4436e8ec
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cvFIDuO6tyqayVcpTo0BM

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability saver-verifier-4436e8ec -d '<json body>'
```

Example prompt: Before you send that report, can you verify the claim that 'global renewable energy capacity surpassed fossil fuels in 2023' — I need to know if it's source-backed and how confident we should be?

## When to prefer this

Choose SAVER Verifier when an autonomous agent needs to gate an action on whether a factual claim is source-backed before proceeding — especially in high-stakes workflows like publishing, decision-making, or acting on retrieved information. Prefer this over generic search when you need a structured verdict (supported/refuted/unverifiable), a confidence score, and cited evidence rather than raw search results. Best suited for single discrete claims rather than broad topic research.

## Known failure modes

- Claim is too vague or ambiguous to verify — returns low confidence or 'unverifiable' status
- No authoritative sources found for an obscure or niche claim
- Claim is in a domain with rapidly changing facts where sources may be outdated
- Malformed or empty claim field causes validation error
- Rate limiting or payment failure results in 402 or 429 response

## How this service works

SAVER Verifier — source-backed factual claim verification for autonomous AI agents.

## Output

Returns a JSON object with a 'status' field (e.g. 'supported', 'refuted', 'unverifiable'), an 'evidence' array of relevant authoritative source excerpts or references, a 'confidence' score between 0 and 1, and an 'explanation' summarizing why the claim was or was not supported.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "claim": {
   "type": "string"
  },
  "context": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "status": "supported",
  "evidence": [
   "Relevant authoritative sources support the claim."
  ],
  "confidence": 0.98,
  "explanation": "The available evidence supports the claim."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saver-verifier-4436e8ec/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.saververify.com](https://www.zero.xyz/host/api.saververify.com/llms.txt)