SReverseby Simpa Labs

Retrofit · Android HTTP APIs

Retrofit API extraction from an Android APK

Retrofit declarations reveal routes and fields. The working API also depends on the OkHttp client, converters, interceptors and session code around them. We rebuild the complete stack.

Retrofit describes the server API specification

Retrofit turns a Java or Kotlin interface into HTTP calls. Its method annotations define verbs and relative paths. Parameter annotations mark path values, query values, headers, bodies, forms and multipart parts. These declarations create a strong endpoint map even after class names have been shortened.

The interface is only the first layer. Retrofit uses a base URL, converter factories and call adapters. A converter controls the bytes sent for a model and the object created from a response. A call adapter controls whether the call returns a Retrofit call, coroutine result, reactive type or another wrapper.

The OkHttp layer changes every call

Retrofit sends requests through OkHttp. Application interceptors can add authentication, device headers, signatures and retries. Network interceptors can see redirects and the request that reaches the wire. An authenticator may refresh a token after a 401. Cookie storage, TLS settings and a custom request body can sit below the Retrofit interface.

We join the service declarations to the exact client instance that runs them. This prevents false endpoint lists built from unused interfaces or test code. Live requests confirm the active base URL, query encoding, body bytes, header order where relevant and response model.

The full APK becomes a full callable API

We rebuild the application’s complete server-facing behavior. The delivery includes Python, JavaScript and TypeScript clients, an importable Postman collection, and working request examples. Authentication, cookies, refresh rules, request order and error handling are built in.

Signature generation runs with fresh timestamps and nonces. Encryption and decryption are implemented in code. Binary bodies are serialized correctly. Each client can start a new session and repeat the application workflows without reusing an old capture.

We test the clients against the same server flows used by the APK. Send the APK on WhatsApp or by email. We handle the technical questions in the conversation.

Reviewed 30 August 2026 · SReverse research desk

One full APK. One complete delivery.

Projects start at $120. Most are delivered in 24 to 72 hours.

Every format included

Python, JavaScript/TypeScript, Postman and complete API documentation cover the same full endpoint set. Your team runs the clients in its own server or system.

Ready in 24–72 hours

The delivery window starts after we receive the APK and any account access needed to run it. The fixed quote states the deadline. Most projects finish sooner.

Deployment checked before the quote

The package includes signing, encryption, decryption and session handling. We verify device-bound keys and server integrity checks during review and document runtime requirements before you commit.

30 days of fixes

Report a defect within 30 days of delivery. We fix any delivered call that does not match the tested APK at no extra cost.

Start your full APK reconstruction

Send the full APK

Projects start at $120. Choose WhatsApp or email, then attach the APK in the app that opens. We reply within one hour with the next step and send the fixed quote after review.

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