---
title: "TypeScript vs Flow"
slug: "typescript-vs-flow"
category: "comparisons"
tags: ["comparisons", "typescript", "flow", "static-typing", "javascript", "tooling"]
status: "stable"
last_updated: 2026-10-01
summary: "Use TypeScript for every new project (TypeScript 7 is the native Go compiler); keep Flow only in codebases that already run it under active Meta-style tooling."
related: ["[[comparisons/typescript-vs-javascript]]", "[[comparisons/swc-vs-babel]]", "[[comparisons/eslint-vs-biome]]", "[[coding/typescript]]", "[[comparisons/jest-vs-vitest]]", "[[comparisons/vite-vs-webpack]]", "[[tooling/github]]"]
---

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>
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## Overview

Use TypeScript for new code and treat Flow as a legacy dependency to keep only while it earns its place. TypeScript 7.0 (released 2026-07-08) is a Go rewrite of the compiler that its authors describe as about 10 times faster than 6.0, the last JavaScript-based release. Flow is still released (`flow-bin` 0.333 in September 2026) but its ecosystem is narrow. React Native's own template targets TypeScript by default, with JavaScript and Flow still supported.

## Comparison

| Dimension | TypeScript 7 | Flow |
| --- | --- | --- |
| Library types | Built in or `@types/*` (DefinitelyTyped) | Inline types or `flow-typed` stubs; coverage is far smaller |
| Build step | Strip with SWC, Oxc, esbuild, or Node 22.18+ native stripping; check with `tsc` | Babel or `flow-remove-types` |
| Frameworks | React, Vue, Angular, Svelte, Next.js, Astro | React and React Native |
| Recent direction | Native compiler, ongoing language work | React component and hook syntax, mapped and conditional types, literal inference |

## Pick TypeScript when

Pick TypeScript for any project that is not already on Flow.

- Nearly every major library ships TypeScript types or has `@types/*` coverage.
- Node.js strips TypeScript types by default since 22.18 and 23.6, but it ignores `tsconfig.json` and rejects enums, runtime namespaces, and parameter properties; use `erasableSyntaxOnly` to keep code compatible.
- Turn on `strict: true`; see [[coding/typescript]].
- Hiring, tooling, and answers (including from LLM agents) overwhelmingly assume TypeScript.

## Pick Flow when

Keep Flow only if all of these hold.

- The codebase already uses Flow and the team maintains type coverage and keeps `flow-bin` current.
- The stack is React Native or Relay and depends on Flow-specific syntax or Meta tooling.
- Conversion cost is larger than the cost of a narrow ecosystem.

## Migrate from Flow

Convert module by module; the two type systems cannot be mixed within one file.

- Use `flow-to-ts` for mechanical syntax conversion, then fix by hand. Note its last release was in 2019, and `ts-migrate` (2022) is also unmaintained; expect manual work on opaque types, variance, and `$ObjMap`-style utilities.
- Keep Flow and TypeScript in separate packages during the transition.
- Source missing third-party types from DefinitelyTyped.
- Moving from TypeScript back to Flow has no supported path.

## Related

- [[comparisons/typescript-vs-javascript]]
- [[comparisons/swc-vs-babel]]
- [[comparisons/eslint-vs-biome]]
- [[coding/typescript]]
- [[comparisons/jest-vs-vitest]]
- [[comparisons/vite-vs-webpack]]
- [[tooling/github]]