# Transaction Assurance

> Transaction Assurance is a paid API for AI agents from phion.systems, paid per call via x402, $0.015/call, status unknown (last checked 2026-10-20).

Independently verifies authorization, settlement, delivery, and deterministic acceptance of a transaction, then returns a signed portable assurance receipt

## Facts

- Endpoint: POST https://phion.systems/v1/paid/transaction-assurance?utm_source=zero.xyz
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/transaction-assurance-3c582123
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GCK-Z_b31IgK6pVBoKSdX

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 transaction-assurance-3c582123 -d '<json body>'
```

Example prompt: Can you independently verify that this transaction was properly authorized, settled, and delivered — and give me back a signed portable assurance receipt I can use as proof?

## When to prefer this

Choose this endpoint when you need independent, third-party verification of a payment transaction's full lifecycle — authorization, settlement, delivery, and acceptance — and require a signed portable receipt as cryptographic proof. Prefer it over simple payment status checks when auditability, non-repudiation, or cross-agent trust is required, such as before releasing goods, granting access, or chaining agent actions that depend on a confirmed prior payment.

## Known failure modes

- Transaction not found or unrecognizable — returns error indicating the provided transaction data could not be located or matched
- Authorization check fails — receipt indicates the transaction was not properly authorized
- Settlement not confirmed — assurance result shows settlement has not completed or is pending
- Delivery unverifiable — endpoint cannot confirm delivery status and flags it in the receipt
- Malformed input — missing or invalid transaction fields result in a validation error
- Deterministic acceptance not met — transaction fails acceptance criteria and receipt reflects rejection

## How this service works

Independently verify authorization, settlement, delivery and deterministic acceptance; return a signed portable assurance receipt

## Output

A signed portable assurance receipt confirming the independent verification of transaction authorization, settlement, delivery, and deterministic acceptance — usable as cryptographic proof that the transaction completed correctly.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input",
  "output"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "additionalProperties": true
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "example"
   ],
   "properties": {
    "example": {
     "type": "object",
     "additionalProperties": true
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/transaction-assurance-3c582123/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from phion.systems](https://www.zero.xyz/host/phion.systems/llms.txt)