Keyword Research API

SEO keyword research -- Google Suggest, intent classification, long-tail discovery, related queries. Content planning. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "keyword-research": {
      "url": "https://keyword-research.api.klymax402.com/mcp"
    }
  }
}

Related MCP server: @seodesignlab/mcp-server

Quickstart -- HTTP (x402)

curl "https://keyword-research.api.klymax402.com/api/keywords?query=..."
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

seo_research_keywords

Use this when you need keyword ideas, SEO research, or content planning data for a topic. Returns keyword suggestions and intent data in JSON.

Parameters

Example response:

{"query":"bitcoin trading","suggestions":["bitcoin trading platform","bitcoin trading bot","bitcoin trading for beginners"],"relatedQueries":{"vs":["bitcoin trading vs investing"],"howTo":["how to start bitcoin trading"]},"longTailKeywords":["best bitcoin trading app 2026","bitcoin trading strategy for beginners"],"searchIntent":"commercial","totalKeywords":47}

When to use: writing blog posts, FOR SEO content strategy, topic cluster planning, content gap analysis, and competitive keyword research.

Not for: page SEO audit (use seo_audit_page), content extraction (use web_scrape_to_markdown), domain intelligence (use domain_lookup_intelligence).

seo_research_keywords

Use this when you need keyword ideas, SEO research, or content planning data for a topic. Returns keyword suggestions and intent data in JSON. POST variant of seo_research_keywords -- same params passed as JSON body instead of query string.

Parameters

Example response:

{"query":"bitcoin trading","suggestions":["bitcoin trading platform","bitcoin trading bot","bitcoin trading for beginners"],"relatedQueries":{"vs":["bitcoin trading vs investing"],"howTo":["how to start bitcoin trading"]},"longTailKeywords":["best bitcoin trading app 2026","bitcoin trading strategy for beginners"],"searchIntent":"commercial","totalKeywords":47}

When to use: writing blog posts, FOR SEO content strategy, topic cluster planning, content gap analysis, and competitive keyword research.

Not for: page SEO audit (use seo_audit_page), content extraction (use web_scrape_to_markdown), domain intelligence (use domain_lookup_intelligence).

Example agent prompts

• "Keyword ideas, SEO research, or content planning data for a topic"

• "Keyword ideas, SEO research, or content planning data for a topic"

Payment

• Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key

• Network: Base L2 (eip155:8453)

• Asset: USDC

• Facilitator: Coinbase CDP (primary), PayAI (fallback)

• Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

• Catalog: https://klymax402.com/llms.txt

• Full API reference: https://klymax402.com/llms-full.txt

• Live stats: https://klymax402.com/stats

License

MIT