# Deal Verdict API – Used Market

> Deal Verdict API – Used Market is a paid API for AI agents from deal-verdict-api-production.up.railway.app, paid per call via x402, $0.08/call, status unknown (last checked 2026-09-14).

Checks whether a specific used product is meaningfully discounted right now on used-market retailers (e.g. eBay) and returns a single deal/no-deal verdict with confidence and discount data.

## Facts

- Endpoint: POST https://deal-verdict-api-production.up.railway.app/verdict/used
- Price: $0.08/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/deal-verdict-api-used-market-3a52529d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_D9YWomqEwbjiXmAoOIwZs

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 deal-verdict-api-used-market-3a52529d -d '<json body>'
```

Example prompt: Check if a used Sony A7III mirrorless camera is genuinely discounted right now — I want at least a 15% discount compared to the typical used market price before I'd consider it a deal.

## When to prefer this

Choose this endpoint when the user specifically wants to evaluate a used or secondhand product's price against the prevailing used-market rate — not new retail price. Use this over the standard verdict endpoint when condition is 'used' and you want the discount benchmarked only against other used listings, never new retail prices. Ideal for eBay-style secondhand market checks.

## Known failure modes

- Insufficient data: not enough used listings found to establish a reliable market basis price, returns 'insufficient_data' verdict
- Sources unreachable: eBay or other used-market retailers are temporarily inaccessible, returns partial or insufficient_data result
- Ambiguous product query: vague product name leads to mismatched listings and unreliable verdict
- Threshold not met: used price exists but discount is below the requested threshold, returns 'no_deal'
- No used listings found: product has no secondhand listings at the moment, returns insufficient_data

## How this service works

Answers one question for any product: is it meaningfully discounted right now at any retailer we can reach? Returns a resolved verdict - deal / no deal / insufficient data - never a data feed.

## Output

A JSON object with a verdict field ('deal_found', 'no_deal', or 'insufficient_data'), the best discount percentage found, the retailer offering the best price, the used-market basis price used for comparison, a human-readable summary explaining the verdict, a confidence level ('high'/'medium'/'low'), and lists of sources checked and sources unreachable.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "product": {
   "type": "string",
   "description": "The product to shop for used, in plain language."
  },
  "category": {
   "type": "string",
   "description": "Optional coarse category hint."
  },
  "location": {
   "type": "string",
   "description": "City or ZIP. Required for Facebook Marketplace; localizes results."
  },
  "variants": {
   "type": "array",
   "items": {
    "type": "string"
   },
   "description": "Optional size/variant hints."
  },
  "attribute": {
   "type": "string",
   "description": "A required attribute, e.g. 'stainless'."
  },
  "product_url": {
   "type": "string",
   "description": "Optional product page to pin the exact model. Never echoed."
  },
  "radius_miles": {
   "type": "integer",
   "description": "Facebook Marketplace search radius, miles."
  },
  "discount_threshold": {
   "type": "number",
   "description": "Fraction under the used-market basis to count as a deal."
  },
  "include_marketplace": {
   "type": "boolean",
   "description": "Opt in to Facebook Marketplace (slow; its own city/radius)."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "mode": "used",
  "basis": "used_market_history",
  "leads": [],
  "price": 1800,
  "summary": "A used deal was found: ebay has a used unit at $1,800.00, 18.2% below the $2,200.00 used-market price for a comparable condition, meeting your 15% threshold. Judged only against other used listings, never new retail.",
  "verdict": "deal_found",
  "retailer": "ebay",
  "condition": "used",
  "confidence": "high",
  "sources_checked": [
   "ebay"
  ],
  "used_market_basis": 2200,
  "best_discount_found": 0.182,
  "sources_unreachable": [],
  "threshold_requested": 0.15
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/deal-verdict-api-used-market-3a52529d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from deal-verdict-api-production.up.railway.app](https://www.zero.xyz/host/deal-verdict-api-production.up.railway.app/llms.txt)