# FastX402 Semver Match

> FastX402 Semver Match is a paid API for AI agents from fastx402.tools, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-17).

Given a list of semantic versions and a semver range constraint, returns which versions satisfy the constraint along with the highest matching version and match count.

## Facts

- Endpoint: GET https://fastx402.tools/semver-match?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fastx402-semver-match-0b993871
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cHamizehEJMotQGpTxlEU

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 fastx402-semver-match-0b993871
```

Example prompt: From these versions — 1.0.0, 1.2.3, 2.0.0, 2.4.0, 2.5.1, 3.0.0 — which ones satisfy the constraint ^2.4.0, and what's the highest match?

## When to prefer this

Use this endpoint when you need to programmatically evaluate which versions from a known set satisfy a semver range — ideal for CI/CD pipelines, dependency resolution logic, release automation, or any agent workflow that needs to pick the best compatible version from a list without spinning up a local Node.js/semver environment. Prefer this over general-purpose code execution when the task is purely semver filtering and you want a fast, cheap, stateless call.

## Known failure modes

- Malformed semver strings in the versions list may cause parsing errors or be skipped
- Invalid constraint syntax returns an error response
- More than 200 characters in constraint or versions string may be rejected
- Pre-release version matching can produce unexpected results if constraint does not explicitly include pre-release tags
- No matches found returns an empty matches array with count 0

## How this service works

146 pay-per-call tools for AI agents, from $0.001 per request in USDC on Base or Solana with x402. No account, no API key.

## Output

A JSON object containing: the constraint string echoed back, the total number of versions checked, the count of matching versions, an array of the matching version strings, and the highest (latest) version among the matches.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "versions",
      "constraint"
     ],
     "properties": {
      "versions": {
       "type": "string",
       "description": "Comma-separated semantic versions, e.g. 1.2.3,2.0.0-rc.1 (max 200)"
      },
      "constraint": {
       "type": "string",
       "description": "Semver range: ^, ~, >, >=, <, <=, =, x-ranges, hyphen ranges, space for AND, || for OR (max 200 chars)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "count": {
       "type": "integer"
      },
      "checked": {
       "type": "integer"
      },
      "highest": {
       "type": "string"
      },
      "matches": {
       "type": "array",
       "items": {
        "type": "string"
       }
      },
      "constraint": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 2,
  "checked": 6,
  "highest": "2.5.1",
  "matches": [
   "2.4.0",
   "2.5.1"
  ],
  "constraint": "^2.4.0"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fastx402-semver-match-0b993871/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fastx402.tools](https://www.zero.xyz/host/fastx402.tools/llms.txt)