Lingo.dev is a localization engineering platform for software teams. Teams configure localization engines, stateful translation APIs that hold a glossary, brand voice rules and per-locale model preferences, and every translation is scored against the team's own criteria before it goes live. Retrieval augmented localization sends that context to the best-scoring LLM for each language pair, an edit in the code repository or CMS kicks off a pipeline, and native-speaking proofreaders approve translations where the team decides. The CLI is open source under Apache-2.0, handles 18 file formats from JSON and YAML to XLIFF, Flutter ARB and Xcode strings, and has about 5,400 GitHub stars.
The company started as Replexica at a hackathon in December 2023, where the prototype won best dev tool, found its first paying customers, went through Y Combinator's Fall 2024 batch and took the Lingo.dev name that December. It now counts hundreds of users, a CLI that runs more than 10,000 times a week and over 300 million translated words, with Mistral, Solana, SoSafe, Cal.com (36 languages), freenet, Maze and Formbricks among the customers. Lingo.dev v1.0 shipped in March 2026 with research showing a 17 to 45% cut in terminology errors from retrieval augmented localization across five LLM providers. The platform is SOC 2 Type II, GDPR and CCPA compliant.