The Best Feature Flags for TypeScript in 2025
For TypeScript developers building modern SaaS applications, feature flags have become essential infrastructure. But while the market offers dozens of options, most solutions treat TypeScript as an afterthought despite adoption soaring past 60% of professional developers.
Traditional platforms like LaunchDarkly focus on enterprise B2C use cases, while newer alternatives often lack the TypeScript-native experience modern development teams demand, so let’s take a look at some of the best options available:
#1 Top Pick for TypeScript: Reflag
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Score: 5/5
Reflag is the first feature flag platform built specifically for SaaS teams using TypeScript.
Native TypeScript integration
The platform's CLI automatically generates comprehensive type definitions for all flags, ensuring compile-time safety and eliminating runtime errors from typos or undefined flags. With a `npx @reflag/cli new` command, you can initialize a project, create flags, and generate types in a single step. This tight integration enables developers to maintain their flow without context switching between tools.
There are native SDKs for React, Vue, Node, Next and a client-side Browser SDK. Types are bundled together with the library and exposed automatically when importing through a package manager.
Self-cleaning flags
Reflag’s focus on TypeScript has enabled it to innovate, such as releasing the first-ever self-cleaning flags.
Flag cleanup is a bugbear for anyone who uses flags day-to-day. Traditional feature flag implementations require manual cleanup processes that development teams often defer indefinitely. Reflag's automated approach eliminates this technical debt before it accumulates, maintaining code quality while reducing maintenance overhead.
Reflag’s self-cleaning flags auto-detect stale flags, and generate PRs to remove obsolete flag code for you, archiving the flags once merged.
While Reflag leads the TypeScript-first category, other solutions deserve consideration for specific use cases.
#2 All-in-one solution: PostHog
Score: 4/5
PostHog feature flags are fully usable within TypeScript projects, and PostHog’s main libraries provide TypeScript types to ensure correct usage of feature flag APIs. PostHog’s browser library (posthog-js) and React hooks (posthog-js/react) offer built-in TypeScript support, letting developers get type-checked access to feature flag values, variants, and payloads. However, its support could be improved by defining feature flag schemas in TypeScript.
Overall, though, PostHog has a unique approach in combining feature flags with a comprehensive platform. Their website claims “We’re building every tool for product engineers,” and it really is an expansive offering. As a result, few people choose PostHog for its feature flag capabilities alone. Its strength is as an all-in-one tool. Although, this breadth means its feature flagging functionality lacks depth. For example, PostHog lacks self-cleaning flags, Linear integration, release stages, and the data export capabilities that Reflag offers.
Plus, all the products makes for a confusing UI if all you want is to roll out features.
Instead, PostHog can be used alongside Reflag to get best-in-class feature flags with Reflag, while using the rest of the PostHog platform.
#3 Enterprise solution: LaunchDarkly
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Score: 4/5
For organizations looking for an enterprise solution with mature feature management capabilities with TypeScript support, LaunchDarkly is a safe bet.
LaunchDarkly feature flags support usage with TypeScript and provide several type definitions to enhance type checking in both Node.js and React projects. However, it’s not fully type-safe and does not offer native schema enforcement for flag values. This means importing the relevant SDKs in a TypeScript project will give autocompletion and basic type safety for standard flag types, but custom app setups may require some type coercion or adjustments as it doesn’t offer strict compile-time flag schemas or automated flag type inference.
Beyond TypeScript, LaunchDarkly’s platform has developed to incorporate observability, experimentation, and analytics capabilities alongside feature flags. This is compelling but contributes to the complexity and price of their solution, which increasingly is best fit for large B2C organizations rather than agile SaaS teams.
While they claim ‘automated flag cleanup’ support, their solution doesn’t actually clean up the flags. Instead, it implements checks that highlight stale flags. This is nice, but you’re still on the hook to do the cleanup work.
Conclusion
As TypeScript adoption continues its upward trajectory, development teams can now prioritize tools built with type safety and developer experience at their core. Reflag delivers on the need for a TypeScript-native solution that integrates seamlessly into modern development workflows.