tieline

Static frontend↔backend contract-drift checker. Pact without writing a single contract test.

tieline reads the code you already wrote on both sides of an API boundary — the HTTP calls your frontend makes and the routes your backend exposes — and tells you where they disagree. No contract tests to author, no broker to run, no backend to boot. It finishes in well under a second and is built to run in CI as a gate.

Delete the LLM and a developer still installs it. tieline is a deterministic tool first; an agent reading its output is a bonus.

How it works

  frontend code                                  backend code
  (axios, rtk-query, …)                          (express, nestjs, openapi, …)
        │                                                │
   client adapter                                   server adapter
        │            normalize  ${id} :id {id} → {}       │
        └───────────────►  join on (METHOD, path)  ◄──────┘
                                   │
              ✅ matched   ❌ drift   ⚠️ unverifiable   🟡 dead

Both sides are reduced to a canonical (METHOD, path) and joined. The matcher is adapter-agnostic — any client adapter pairs with any server adapter, so the same engine checks a React app against Express, an Angular app against Spring, or anything against an OpenAPI spec.

tieline vs alternatives

These tools solve neighbouring problems — pick by what you have and what you want guaranteed.

... View full README on GitHub