Base64 Codec X402 MCP Server

Base64 Codec API

Encode text to base64 or decode base64 to text. Supports standard and URL-safe variants with metadata. 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": {
    "base64-codec": {
      "url": "https://base64-codec.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://base64-codec.api.klymax402.com/api/encode" \
  -H "Content-Type: application/json" \
  -d '{"data":"..."}'
# -> 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

utility_encode_base64

Use this when you need to encode text to base64 or decode base64 back to plaintext. Returns the result string with encoding metadata.

Parameters

Example response:

{"result":"SGVsbG8gV29ybGQ=","action":"encode","inputLength":11,"outputLength":16,"urlSafe":false}

When to use: embedding binary data in JSON, preparing email attachments (MIME), or decoding base64 tokens from APIs. Use this BEFORE sending data through channels that only support ASCII.

Not for: hashing (use crypto_generate_hash), JWT decoding (use security_decode_jwt), URL slug creation (use text_generate_slug).

Example agent prompts

• "Encode text to base64 or decode base64 back to plaintext"

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