Open-source Lokalise alternatives

Weblate is a localization tool you use in the browser, closely integrated with version control. You connect your repository, translators work in the browser, and new strings and finished translations flow between the repository and Weblate so localization keeps pace with development.

The project website emphasizes quality and control. Translators get context, shared terminology and quality checks, and teams can work exclusively with people or add AI and machine translation. Repository topics reference gettext, continuous localization and crowdsourcing. It is used by both community projects and commercial products, and the Weblate project itself, along with many open-source applications, are translated on its hosted service.

Weblate is written in Python with Django and licensed under GPL-3.0. The homepage describes it as free to use, inspect, modify and share, suitable for organizations and communities. You can run it yourself or choose hosting and support options, which are compared on the vendor's hosting page.

Lingo.dev is a set of open-source localization engineering tools that connect to the Lingo.dev platform. It is aimed at product teams that translate their software into multiple languages and want that work to be consistent, measurable and automated, instead of passing strings around by hand.

On the platform, teams configure localization engines with glossaries, brand voice and per-locale chains of language models, and call them from code, the command line, CI/CD pipelines or MCP. Quality criteria that teams define in plain words are used to score translations from LLMs and from native speakers, so low-scoring languages can be found and traced back to a model, a rule or a missing glossary term.

The open-source repository, written in TypeScript and licensed under Apache-2.0, includes a command-line tool and a compiler package, and its topics point to React and React Native projects. A hosted platform with sign-in, pricing and enterprise options sits alongside it.

Tolgee is an open-source, web-based localization platform made to be friendly to both developers and translators. It is presented as an alternative to Crowdin, Phrase and Lokalise, with the aim of saving the time that localization tasks usually take.

Its distinctive feature is in-context translation: holding the Alt or Option key and clicking a text in your running app opens a dialog for editing the string, without digging through JSON or PO files. A one-click screenshot feature captures the page with the phrases highlighted, and translation works in production using the Tolgee Tools Chrome plugin with an API key, so non-developers can contribute.

Instead of only syncing files with a backend, Tolgee integrates into the app through SDKs for frameworks such as React, Angular, Vue and Svelte. Machine translation is available through DeepL, Google Translate, AWS Translate and Azure Translator, which speeds up the work of translators. The platform is written mainly in TypeScript.

Pontoon is a translation management system developed and used by the Mozilla localization community. It is built to support open-source localization that is driven by volunteers, and it works with version control systems for storing translations so that work done in the web interface flows back to project repositories.

Users translate strings in a browser-based translation app, while teams and project managers use dashboards to track progress across locales. Mozilla runs staging and production servers of its own, and the documentation explains how Mozilla deploys Pontoon as a Docker image on Google Cloud Platform, noting that other platforms may need adaptation. A separate developer setup is provided for local testing but is not suitable for production.

The software is written in Python and JavaScript on the Django framework and is licensed under the New BSD licence. Organizations can host their own instance, and GitHub Discussions is where feedback, support and third-party deployments are discussed. It suits open-source projects and communities that want to organize volunteer translators without paying for a commercial localization platform.

Intlayer is an internationalization (i18n) solution for web and mobile JavaScript applications. Instead of one large translation file, content is declared per component in per-locale files, which keeps translations next to the code that uses them and gives TypeScript autocompletion.

It is framework-agnostic, with support for Next.js, React, Vite, Vue, Nuxt, Preact, Express and React Native. Dictionaries are tree-shakable, CI/CD integration is available, and AI-powered translation can fill in locales. A free CMS and visual editor let non-developers manage multilingual content without touching code.

The project positions itself as a modern alternative to i18n libraries it considers too complex or too rigid. It is written in TypeScript, licensed under Apache-2.0, and documented with guides for Next.js and React with Vite, plus a Discord community.