FormatJS vs Project Fluent
No leader: the top candidate FormatJS has only 0.22 confidence (low), below the 0.35 needed to declare a winner. The attribute-by-attribute breakdown below, with a source and date on every value, is the honest way to compare them.
Capabilities
Feature-by-feature on the axes that matter for localization i18n. “-” means undocumented, not absent.
What each one is
The product in its own terms, so the numbers below have context.
FormatJS
A monorepo hosting FormatJS libraries, with react-intl as a primary component. Provides tools for implementing internationalization and localization functionality in JavaScript applications.
Project Fluent
A localization system that enables translations to use the full range of grammatical features in their target language, including proper handling of plurals, gender, dates, times, numbers, and right-to-left text.
Pricing
List pricing as published by each vendor, with the date we read it. Always verify at the source before you buy.
FormatJS
Pricing not documented yet.
Platform & deployment
Where each product runs and how it can be hosted. A dash means undocumented, not unsupported.
FormatJS or Project Fluent: which one depends on you
A composite score cannot know your constraints. Describe them and both get re-weighted against what you actually need, with the evidence behind every position.
Free to run, no account needed to start. How the evaluation works
Comparison generated from independently-sourced facts. Every value links to its source and retrieval date. See the method.