Merit Systems Authentication

generated: '2026-07-20'
method: searched
source:
  - https://github.com/merit-systems/sdk/blob/master/api.md
  - https://agentcash.dev/openapi.json
summary:
  types: [apiKey, x402, mpp, siwx]
  api_key_in: [header]
  notes: >-
    Two distinct auth models across Merit's surfaces. The Merit Systems REST API
    uses a static API key header. AgentCash uses wallet-based auth: free
    "SIWX" (Sign In With X-chain wallet) endpoints via a signed header, and paid
    endpoints settled per-call over x402/MPP micropayments (HTTP 402) — no API
    keys required for paid calls.
schemes:
  - name: apiKey
    api: Merit Systems API
    type: apiKey
    in: header
    parameter: x-api-key
    source: openapi/merit-systems-merit-api-openapi.yml
  - name: siwx
    api: AgentCash
    type: apiKey
    in: header
    parameter: SIGN-IN-WITH-X
    description: Sign In With X — wallet-based identity header for free AgentCash endpoints (search, invite-codes, organizations).
    source: openapi/merit-systems-agentcash-openapi.json
  - name: x402
    api: AgentCash
    type: payment
    scheme: x402
    description: >-
      HTTP-native micropayment protocol. Paid endpoints (e.g. POST /api/send)
      return 402 Payment Required; the agent's wallet settles the payment in
      USDC (Base, Solana, or Tempo) inside the same request. No accounts or API
      keys.
    networks: [base, solana, tempo]
    currency: USDC
  - name: mpp
    api: AgentCash
    type: payment
    scheme: mpp
    description: Machine Payments Protocol — per-request server payment, alternative rail to x402.