“The fifth developer is an AI”: startup moves its entire backend to pair programming with a model

A European SaaS startup has announced that its core product team now includes a “virtual developer” – a specialized AI agent permanently connected to the repository and the issue tracker. Its role is not only to generate code on demand, but also to proactively suggest refactoring, detect duplication, write documentation and draft migration plans whenever the architecture changes. According to the company, a team of four people has now reached the productivity of roughly six to seven experienced engineers, while maintaining quality control.

The AI agent is integrated with version control: it creates separate branches, writes meaningful commit messages, attaches auto‑generated tests to each change and provides a brief technical summary. Human developers still have the final say – they accept or reject merge requests, and the agent further trains on their comments. A dedicated module tracks code style, established team practices and the tech stack, so the suggested changes “look as if they were written by the same person who wrote the rest of the project.”

After three months of use, the company reports fewer regression bugs and almost a twofold reduction in time spent on routine tasks such as building standard APIs, performing database schema migrations and tweaking configs. Developers say the hardest part is not technical but organizational: getting used to a “fifth entity” in the tracker and code review that never gets tired and constantly proposes improvements. Several other startups have already requested access to the technology as a B2B service, and experts expect the emergence of a whole class of “AI teammate” products across different fields – from software engineering to law.