Comby review
A free, open-source tool for structural code matching and rewrite automation.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Comby is an open-source command-line tool for searching, matching, and rewriting code structures across many programming languages and data formats. It is aimed at developers handling one-off refactoring, large-scale code changes, reusable rewrite rules, and pattern-based maintenance. Structural matching covers balanced delimiters, strings, and comments, giving Comby a focus beyond plain text search while retaining embedded PCRE regular-expression support.
Its standout capability is template-driven structural rewriting. Named holes let users describe the parts of a pattern that may vary, then reuse those values in proposed changes. Recursive directory processing and file filtering extend that approach across a codebase, while interactive review provides a step for inspecting changes before applying them. Configuration files and reusable rewrite-template catalogs support repeatable workflows, and JSON-lines output exposes matched ranges and holes for downstream processing.
Comby runs locally through pre-built binaries, source installation, Docker, Python bindings, or a local HTTP server. Its Windows, macOS, and Linux support suits teams that want codebase processing under their own control, while the Python bindings and HTTP API provide integration paths beyond the command line. The tradeoff is that Comby is a self-hosted tool rather than a managed service, so teams need to choose and maintain their preferred installation and execution method. Pick it for structural search-and-rewrite automation with reviewable, reusable rules; choose another tool if the priority is a non-technical interface or a hosted workflow.
Comby pros and cons
- Where it wins
- Matches balanced code blocks, strings, and comments structurally
- Named-hole templates support repeatable search-and-rewrite workflows
- Interactive review, JSON-lines output, and local API access
- Where it doesn't
- Self-hosted operation places setup and runtime management on the team
- Command-line workflows may be less suitable for non-technical users
- Rewrite automation requires creating templates and configuring matching rules
Comby fact sheet, pricing and score →
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