Python backends, APIs and integrations

From business rules to an API

We start with what the product must do and who is allowed to do it. Payments, access, stock, documents and processing jobs each have different data and constraints. I use those requirements to design the database, API and module boundaries. FastAPI or Django is a choice based on the job and the existing codebase, not a checklist.

Not every integration has a ready-made API

GNU Backgammon had no suitable API for LearnBG. I built a wrapper around its CLI and parsed its output so the analysis could become part of a web product. When the documentation does not cover your use case, I first investigate the available interfaces and constraints. A missing SDK is not necessarily a dead end.

Keep long-running work out of the request

Game analysis or a large file batch should not leave the interface waiting on an open HTTP request. LearnBG uses a separate worker, RQ, Redis and S3 for this. For your system, we will separate immediate operations from background jobs and define how users see progress and receive results.

Build it to fit the surrounding system

An API may serve a React interface, a Telegram Mini App or another company’s system. Data formats, authorization, errors and compatibility need agreement. When joining an existing product, I begin with its contracts and dependencies so a change in one service does not silently break another.

The job continues through launch

The code needs an environment, configuration, access controls and a working database. I can handle that technical work as part of the agreed scope, along with later maintenance. You can also bring a single integration into an existing project; a new backend from scratch is not a prerequisite.

What helps us get started

• The user or business action you want to enable
• External API documentation, if available
• The existing stack and constraints, without secret keys

Missing something from the list? That does not prevent us from starting. Just explain the situation in your own words.