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Example Apps

enlace-examples has a runnable sample app per adapter — aspnetcore/, express/, fastapi/, java/, nest/ — each already wired up to Enlace, so you can see a real chain working before you touch your own API.

🚀 Try it live — no setup at all​

The fastapi/ example is deployed and running right now, Postgres-backed, with real OAuth2 auth:

👉 enlace-fastapi.onrender.com/enlace

Open it, drop in the seeded demo credentials, and build the chain below — nothing to install, nothing to run locally.

The two reference chains​

The four CRUD-only examples (aspnetcore/, express/, java/, nest/) implement one shared, unauthenticated contract — customers, products, orders — so a chain built against one works unmodified against any other:

  1. POST /customers — capture the new customer's id.
  2. POST /products (×2) — capture both ids.
  3. POST /orders, mapping customerId from step 1 and each item's productId from step 2 — capture the order's id and its server-computed total.
  4. PUT /orders/{id}/status, with id mapped from step 3, body { "status": "paid" }.
  5. GET /orders/{id} — confirm the status change.

fastapi/ goes further: it's the production reference implementation — three real credential types across three actors (customer, admin, carrier), a compound cart→checkout→payment→fulfillment→shipment flow, and an 8-step chain with two credential switches mid-run:

  1. GET /products (no credential) — pick a product's id.
  2. POST /carts (customer credential) — capture the cart's id.
  3. POST /carts/{cartId}/items, productId mapped from step 1.
  4. POST /carts/{cartId}/checkout — capture both order.id and payment.id out of one compound response.
  5. POST /payments/{id}/confirm, id mapped from step 4's payment.id.
  6. POST /orders/{id}/fulfill, id mapped from step 4's order.id — switch to the admin credential here — capture the shipment's trackingNumber.
  7. PUT /shipments/{trackingNumber}/status, mapped from step 6 — switch to the carrier credential here.
  8. GET /shipments/{trackingNumber} (no credential) — confirm status: "delivered".

See fastapi/README.md for the exact demo credential values, or CONTRACT.md for the full API shape behind both chains. The CRUD-only examples will grow into this same richer contract over time — for now, fastapi/ is the one that's actually there, and it's the one that's live.