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Rails at a glance

x402

Endpoint style: /{network}/*

MPP (Tempo)

Endpoint style: /mpp/*

MPP (Solana)

Endpoint style: /mpp-solana/*

Protocol differences

Topicx402MPP
Challenge headerPayment-Required + accepts[]WWW-Authenticate: Payment ...
Retry headerPAYMENT-SIGNATUREAuthorization: Payment ...
Typical success signalJSON paid: truePayment-Receipt header + JSON
Discovery source/.well-known/x402OpenAPI (/openapi*.json)

Naming differences to watch

x402MPP
repostsxreposts
commentsxcomments
bookmarksxbookmarks
dexdex-rocket

Amount defaults and requirements

  • x402 social quick routes often allow omitted amount and default to 40.
  • MPP social routes usually require explicit amount (or equivalent winners alias).
  • Many quick social actions are priced per slot (commonly $0.025, with some follower/member flows at $0.04).

x402 flow

  1. Call paid /{network}/... endpoint without payment.
  2. Receive 402 with requirements.
  3. Sign challenge data and retry with PAYMENT-SIGNATURE.
  4. Store returned jobId and secret when present.

MPP flow

  1. Call /mpp/... or /mpp-solana/... without Authorization.
  2. Receive 402 with payment challenge in WWW-Authenticate.
  3. Build payment credential from challenge.
  4. Retry with Authorization: Payment ....
  5. Store Payment-Receipt.

Choosing the right rail

  • You already use x402 clients (@x402/fetch).
  • Your workload is mostly on /{network} endpoint families.
  • You want simple challenge -> signature -> retry behavior.

Practical rail selection

SituationRecommended choiceWhy
First-time WURK integratorx402 on SolanaFastest path to first paid success
Existing Payment credential stackMPP TempoNative auth model for MPP clients
Solana MPP-native infraMPP SolanaStrong alignment with Solana MPP tooling

Runtime availability

  • x402 routes are generally available with the x402 server rail.
  • MPP Tempo routes depend on MPP Tempo enablement.
  • MPP Solana routes depend on MPP Solana enablement.
  • OpenAPI documents can be reachable even when specific runtime rails are disabled.

Canonical references

  • https://wurkapi.fun/.well-known/x402
  • https://wurkapi.fun/openapi-x402.json
  • https://wurkapi.fun/openapi.json
  • https://wurkapi.fun/openapi-mpp-solana.json
  • https://wurkapi.fun/skill.md