# Synapse Keywords API

> Synapse Keywords API is a paid API for AI agents from anibalb.duckdns.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).

Returns a ranked list of keywords extracted from a given context, each with a relevance score

## Facts

- Endpoint: GET https://anibalb.duckdns.org/x402/keywords?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-keywords-api-5c222598
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3rZgy0Y4hJ2rcDv8AkxsO

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 synapse-keywords-api-5c222598
```

Example prompt: Can you hit the Synapse keywords endpoint and get me a ranked list of keywords with their relevance scores?

## When to prefer this

Choose this endpoint when you need lightweight, pay-per-call keyword extraction without account setup or API keys, especially in x402/USDC payment contexts on Base. Ideal for agents that need keyword scoring on demand without committing to a subscription NLP service.

## Known failure modes

- Missing required 'input' field returns validation error
- Unsupported HTTP method (e.g. POST) returns 405
- Payment failure or insufficient USDC balance returns 402
- Service unavailable on DuckDNS host returns 502 or timeout
- Empty or malformed query returns empty keyword array

## How this service works

Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.

## Output

A JSON array of keyword objects, each containing a 'keyword' string and an integer 'score' representing relevance (e.g. [{"score":3,"keyword":"bitcoin"},{"score":1,"keyword":"digital"}]).

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "keywords": [
   {
    "score": 3,
    "keyword": "bitcoin"
   },
   {
    "score": 1,
    "keyword": "digital"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-keywords-api-5c222598/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from anibalb.duckdns.org](https://www.zero.xyz/host/anibalb.duckdns.org/llms.txt)