# SpyFu Related Keywords API

> SpyFu Related Keywords API is a paid API for AI agents from spyfu.x402.paysponge.com, paid per call via x402, $0.01/call, status down (last checked 2026-09-14).

Returns related keywords for a given seed keyword using SpyFu's keyword relationship data

## Facts

- Endpoint: GET https://spyfu.x402.paysponge.com/apis/keyword_api/v2/related/getRelatedKeywords
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-09-14
- Activations on Zero: 2
- Tags: x402
- Canonical page: https://www.zero.xyz/c/spyfu-d6f6654b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hwPYpVnHffC3JPjUCasdz

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 spyfu-d6f6654b
```

Example prompt: What keywords are related to 'project management software' according to SpyFu? I want to expand my SEO keyword list.

## When to prefer this

Use this endpoint when you need to discover semantically or contextually related keywords for a given seed term, particularly for SEO expansion, content clustering, or paid search campaign broadening. Prefer this over competitor-focused endpoints when the goal is keyword discovery rather than competitive analysis.

## Known failure modes

- Missing required query parameters returns an error or empty result
- Invalid keyword input may return no related keywords
- Payment failure via x402 prevents API access
- Rate limiting if too many requests are made in quick succession

## How this service works

GET /apis/keyword_api/v2/related/getRelatedKeywords

## Output

A list of related keywords associated with the input seed keyword, drawn from SpyFu's keyword relationship database, useful for expanding SEO campaigns and content strategy.

## 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
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "additionalProperties": true
    }
   },
   "additionalProperties": false
  }
 },
 "additionalProperties": false
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/spyfu-d6f6654b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from spyfu.x402.paysponge.com](https://www.zero.xyz/host/spyfu.x402.paysponge.com/llms.txt)