Top AI Agents for Code Migration & Refactoring (2026)
Migrations and large refactors are repetitive and mechanical. They are also easy to get subtly wrong. That is why several tools target them directly. This list covers agents and rewrite engines. Each one's own docs name code migration, framework upgrades, or large-scale refactoring. It also includes general agents that list migration-style tasks. Durable facts only.
Cognition's software-engineer agent. Its docs list code migrations, refactors, and modernizing old code. That includes language moves such as JavaScript to TypeScript, plus framework upgrades.
- Model:
- Hosted SaaS
- Runs:
- Web app + CLI + Slack / Teams
A declarative query language for searching and rewriting source code. Its docs describe large-scale migrations across APIs and frameworks, with support for JavaScript, TypeScript, Python, and Java.
- License:
- MIT (GritQL engine)
- Runs:
- CLI (Rust) + hosted platform
A platform that automates code migrations, framework upgrades, and large-scale changes. It runs from the terminal or CI. The transforms work on the AST and are written in TypeScript.
- License:
- Apache-2.0
- Runs:
- CLI / CI + hosted registry
OpenRewrite is an open-source tool that refactors code with prepackaged recipes. The recipes run through Gradle and Maven. The Moderne platform runs the same recipes across many repositories at once.
- License:
- Apache-2.0 (OpenRewrite)
- Runs:
- Build-plugin engine + Moderne platform
An agentic coding tool whose overview names project-wide tasks such as fixing lint errors across a project and updating dependencies.
- Model:
- Hosted SaaS
- Runs:
- CLI + IDE + web + CI
Sourcegraph's coding agent. Its manual shows migration-style tasks, such as converting CSS files to Tailwind across a project.
- Model:
- Hosted SaaS
- Runs:
- CLI + web + editor
Google's open-source terminal agent. Its README lists handling complex rebases among its example tasks.
- License:
- Apache-2.0
- Runs:
- CLI / terminal
Reviewed quarterly. Durable facts only: what it is, license, where it runs. Stars, pricing, and benchmark scores are left off. They rot too fast to stay right on a static page. Each row carries the date it was last checked against the source.
Common questions
- What is the difference between a rewrite engine and a coding agent for migrations?
- A rewrite engine such as OpenRewrite or GritQL applies fixed rules. The same run always gives the same result. That suits mechanical changes you repeat often. A coding agent reasons case by case, which suits migrations that need judgment. Many teams combine the two: an engine for the bulk change, an agent for the exceptions.
- Can these tools migrate a whole framework version?
- Several name framework upgrades directly: Devin, Codemod, and OpenRewrite all list framework migration in their own docs. The right fit depends on your language and build system. So check what languages each tool supports, and what recipes or transforms it ships.