TypeScript Formatter
Format TypeScript with Prettier — consistent indentation, quotes and semicolons. It runs entirely on your device — nothing is uploaded.
Reviewed by the CalcCafe editorial team · Last updated 1 July 2026 · How we test our tools
Example
Format TypeScript with Prettier — consistent indentation, quotes and semicolons.
How it works
Prettier parses your TypeScript into an AST and re-prints it with a consistent, opinionated style.
Good to know
The TypeScript Formatter takes raw .ts or .tsx source and re-prints it with Prettier 3.3.3's opinionated style, fixing inconsistent indentation, mixed quote styles, missing or stray semicolons, trailing commas, and line wrapping in one pass. It is aimed at TypeScript developers who want a quick, no-install way to clean up a snippet, normalize code copied from a chat or pull request, or sanity-check formatting before pasting it back into a project.
Reach for it when you don't want to wire Prettier into a local toolchain, when you're on a machine without your usual editor config, or when you just need a single file tidied without committing anything. Because Prettier parses your code into an abstract syntax tree before re-printing, it only reformats valid TypeScript — so the tool doubles as a lightweight syntax check: if formatting fails, your input has a parse error somewhere.
Read the result as a faithful, restyled copy of your code: line breaks, spacing, and quotes may change, but the program's behavior does not. Prettier deliberately makes few choices configurable, so the output reflects its defaults (such as double quotes and 80-character print width) rather than your team's .prettierrc.
- Use it for snippets and one-off cleanups, not as a substitute for project-wide formatting in CI.
- If your repo enforces single quotes, 2 vs 4 space tabs, or a wider line length, expect the output here to differ from your committed style.
- Type annotations, generics, and JSX/TSX are preserved — formatting never strips or alters types.
Frequently asked questions
Is my data uploaded anywhere?
No — everything runs in your browser. Your code never leaves your device, so it's safe for private work and runs offline once loaded.
Is this tool free?
Yes, completely free with no sign-up and no limits.
People also ask
What is the difference between a TypeScript formatter and a linter?
A formatter like Prettier only changes how code looks — spacing, quotes, line breaks — without altering behavior. A linter such as ESLint analyzes code for bugs and style-rule violations and can flag or sometimes fix logic and quality issues, which formatting alone does not address.
Does formatting TypeScript change how the code runs?
No. Prettier reprints the same abstract syntax tree, so the program's logic, types, and output stay identical; only whitespace, quote style, semicolons, and wrapping change.
Can this tool format .tsx and React JSX files?
Yes. It loads Prettier's TypeScript and estree plugins, which handle TypeScript syntax including JSX in .tsx files, preserving components and props while normalizing formatting.
Will this formatter use my project's prettierrc settings?
No. It applies Prettier's built-in defaults rather than reading any local configuration file, so options like print width, tab width, and quote style follow Prettier's standard settings, not your repo's custom rules.
Why does Prettier use double quotes by default?
Prettier defaults to double quotes but will keep single quotes if doing so requires fewer escapes; the goal is consistency with minimal escaping. The default can be overridden in a full Prettier setup via the singleQuote option.
What happens if my TypeScript code has a syntax error?
Prettier cannot build an abstract syntax tree from invalid code, so formatting will fail instead of producing output. This means a successful format also confirms your snippet parses as valid TypeScript.
Is it safe to paste private or proprietary code into this tool?
Yes. The tool runs entirely in your browser using a client-side Prettier build, so your code is never uploaded to a server and works offline once the page has loaded.
How does Prettier decide where to break long lines?
Prettier wraps code to fit within its print width (80 characters by default), breaking expressions, arguments, and object literals across lines when they exceed that limit, and collapsing them when they fit.
Which is easier, TS or JS?
JavaScript is easier to start with because you can write and run it with no setup and no type annotations, while TypeScript adds a compile step and a type system you have to learn. TypeScript is often easier to work in once a project grows, because the compiler and your editor catch mistakes and autocomplete against real types. Since TypeScript is a superset of JavaScript syntax, you can learn JS first and add types gradually.
What program opens a tsx file?
A .tsx file is plain text, so any code editor opens it: Visual Studio Code, WebStorm, Sublime Text, Vim or even Notepad. To get syntax highlighting, type checking and JSX support you want an editor with TypeScript support, which VS Code includes out of the box. To actually run it, the file must first be compiled with the TypeScript compiler (tsc) or a bundler such as Vite, esbuild or Next.js.
Can you run TypeScript in a browser?
Not directly: browsers only execute JavaScript, so TypeScript has to be compiled (transpiled) to JavaScript first, which strips the type annotations. In practice a bundler or the tsc compiler does this as a build step, and the browser receives ordinary .js files. Tools like the official TypeScript Playground make it feel like the browser runs TypeScript, but they compile it in the page before executing the result; this formatter likewise runs Prettier in the browser without executing your code at all.
Is tsx a TypeScript file?
Yes. A .tsx file is a TypeScript file that is also allowed to contain JSX, the HTML-like syntax used by React and similar libraries; the extra x comes from XML. The .ts extension is for TypeScript without JSX, where angle brackets are reserved for generics and type assertions. This formatter handles both, since Prettier's TypeScript parser understands JSX.
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