Verification API

Determine whether a claim is supported by the evidence you supply. This is not a chatbot: verification is deterministic, every conclusion traces to a supplied value, and no evidence is ever fabricated. Accepts raw JSON.

Endpoint

POST /api/v1/verify

Metered as one verification per call; evidence volume counts toward your monthly record allowance.

Request fields

Field	Type	Description
claim*	string	The statement to verify. Treated strictly as data, never as instructions.
evidence	object[]	Evidence items. Each is { source?, record_id?, field?, value }. Only these values are ever used.

Result classifications

Field	Type	Description
verified	result	Supplied evidence supports the claim and nothing contradicts it.
contradicted	result	Supplied evidence disagrees with the claim (or both supports and contradicts it).
unsupported	result	Evidence was supplied but none of it bears on the claim.
insufficient_evidence	result	No relevant evidence was supplied to assess the claim.

Evidence & economic integrity

For a monetary claim, the result is only verified when a supplied number actually matches the claimed amount. Counts are never converted into dollars and amounts are never inferred. The response returns the exact supporting and contradicting evidence items plus a confidence derived from that evidence.

Prompt-injection defense

All customer-supplied text — the claim and every evidence value — is treated as data. Instruction-like content (for example "ignore all previous instructions") is detected and ignored; it can never change the verification outcome. When such content is seen, injection_detected is true in the response so you can audit it.

Example request

Request

POST /api/v1/verify
Authorization: Bearer stx_live_...
Content-Type: application/json

{
  "claim": "Customer owes $47,250",
  "evidence": [
    { "source": "billing", "record_id": "inv_881", "field": "amount", "value": 47250 },
    { "source": "billing", "record_id": "inv_881", "field": "status", "value": "unpaid" }
  ]
}

Example response

200 OK

{
  "request_id": "req_xxx",
  "result": "verified",
  "supported": true,
  "confidence": 0.9,
  "evidence": [
    { "source": "billing", "record_id": "inv_881", "field": "amount", "value": 47250, "index": 0 }
  ],
  "contradictions": [],
  "missing_evidence": [],
  "injection_detected": false,
  "reasoning": "A supplied amount matches the claimed amount with no contradicting evidence."
}

Code examples

cURL

curl -X POST https://crossstax.dev/api/v1/verify \
  -H "Authorization: Bearer $CROSSSTAX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "claim": "Customer owes $47,250",
    "evidence": [
      { "source": "billing", "record_id": "inv_881", "field": "amount", "value": 47250 }
    ]
  }'

JavaScript / TypeScript

import { CrossStax } from "@crossstax/sdk"

const crossstax = new CrossStax({ apiKey: process.env.CROSSSTAX_API_KEY! })

const result = await crossstax.verify({
  claim: "Customer owes $47,250",
  evidence: [
    { source: "billing", record_id: "inv_881", field: "amount", value: 47250 },
  ],
})

console.log(result.result, result.confidence) // "verified" 0.9

Python

import os, requests

resp = requests.post(
    "https://crossstax.dev/api/v1/verify",
    headers={"Authorization": f"Bearer {os.environ['CROSSSTAX_API_KEY']}"},
    json={
        "claim": "Customer owes $47,250",
        "evidence": [
            {"source": "billing", "record_id": "inv_881", "field": "amount", "value": 47250},
        ],
    },
)
data = resp.json()
print(data["result"], data["confidence"])