CodeScene

CodeScene answers a different question than the rest of this category: not "write this code for me" but "which part of this codebase is actually dangerous". Its behavioural code analysis combines code metrics with the history of how a file has been changed and by whom, surfacing hotspots — code that is both complex and frequently modified — as the places refactoring effort actually pays off, rather than treating every code-smell warning as equally urgent.

CodeScene AB is Swedish, founded in 2015 by Adam Tornhill in Malmö, and its Core Product is available either as downloadable software you run yourself (CodeScene On Premise) or as CodeScene Cloud. The CodeScene ACE add-on layers AI-based automated refactoring on top, explicitly built on large language models from third-party providers — an opt-in step up from the self-hostable core rather than something forced on every user.

There is no public price list: Community/open-source projects get a free Cloud Service, and On Premise, Cloud and ACE are all quoted through a sales conversation. That is a heavier sales process than most tools here, and CodeScene is an analysis and prioritisation tool rather than an autocomplete or chat assistant — it tells you where to focus, and something else still has to write the fix.

What CodeScene does well

• On Premise option keeps analysis off any vendor's servers
• Behavioural analysis prioritises technical debt by real impact, not just code smells
• CodeScene ACE adds AI-based automated refactoring as an add-on
• Swedish vendor with a decade of research behind the method
• Free Cloud Service for open-source projects

Where CodeScene falls short

• No public pricing — quote-only for every paid tier
• ACE add-on sends code to third-party LLM providers
• Analysis and prioritisation, not code generation
• Best value shows up on larger, older codebases

Standout feature. It ranks technical debt by how the code actually gets changed and by whom — a different, evidence-based answer to "what do we fix first".