Free CSV to TypeScript Converter — generate TypeScript interfaces from CSV in your browser

🧬 CSV to TypeScript — Free Online Tool

Convert CSV to TypeScript online, free. CSV is a flat, row/column tabular format every spreadsheet and database understands. TypeScript interfaces give compile-time types for data crossing your app. CSV to TypeScript conversion parses your CSV against the RFC 4180 grammar (https://www.rfc-editor.org/rfc/rfc4180), builds an in-memory model of its keys, nested objects and arrays, then emits ready-to-use TypeScript types as interfaces with optional members following the TypeScript Handbook conventions. Processing runs in your browser in JavaScript with no upload or server round-trip — no size limit beyond your device's memory, so multi-megabyte documents convert in milliseconds and sensitive payloads never leave your machine. Typical uses include typed API clients, React/Next.js props and shared front/back types.

🚀 Why use this CSV to TypeScript tool?

It maps the full structure of your CSV onto idiomatic TypeScript types, following the TypeScript Handbook conventions. 100% free, no registration, and complete privacy — everything runs locally in your browser, so your data never touches a server.

Key Features

Instant, in-browser

Paste CSV and generate TypeScript types from TypeScript immediately. Conversion runs client-side, so there is no upload wait and large documents stay fast.

🧩Structure-aware mapping

Nested CSV objects, tables and arrays are mapped faithfully onto TypeScript, including nested types and optional fields.

🔒100% private

Your CSV never leaves your device — everything is processed locally in JavaScript, with nothing logged or stored.

🆓Free, no signup

Unlimited conversions with no account, no quotas, and no watermark. Works on desktop and mobile.

Popular Use Cases

Typed models from samples

  • Turn a sample CSV payload into TypeScript types
  • Skip hand-writing boilerplate models
  • Keep front-end and back-end shapes in sync

typed API clients

  • typed API clients
  • React/Next.js props
  • shared front/back types

Onboarding a new API

  • Paste an example CSV response
  • Get typed TypeScript to consume it safely
  • Catch shape mismatches at compile time

What It Handles

Structure

  • Nested objects & tables
  • Arrays / lists
  • Deeply nested documents

Values

  • Inferred types (string, number, boolean)
  • Optional / nullable fields
  • Nested type names

Workflow

  • Copy or download output
  • Load an example to try it
  • Validate & format the input

Worked example

A CSV document and its TypeScript equivalent:

CSV input:

name,age,active
Ada,36,true

Output:

interface Contact {
  name: string;
  age: number;
  active: boolean;
}

Sources & References

Frequently Asked Questions

How do I convert CSV to TypeScript?

Paste your CSV into the editor and press "Convert to TypeScript". The tool parses it against the RFC 4180 grammar, then generates TypeScript types following TypeScript Handbook conventions — instantly and entirely in your browser. You can validate or format the CSV first to be sure it is clean.

How is CSV structure represented in TypeScript?

CSV is flat and untyped: the header row supplies the field names and every column is read as text, so each row becomes one TypeScript record whose fields you may want to retype.

Are optional fields detected when generating TypeScript?

Optional or nullable members in the generated TypeScript are inferred from keys missing in some records of your CSV, following TypeScript Handbook. Include the optional fields in your sample so they are typed correctly.

What is the difference between CSV and TypeScript?

CSV (Comma-Separated Values) (CSV) — CSV is a flat, row/column tabular format every spreadsheet and database understands. TypeScript interfaces (TypeScript) — TypeScript interfaces give compile-time types for data crossing your app. This converter maps the structure of your CSV onto TypeScript so you can use it for typed API clients.

Does the converter validate my CSV first?

Yes. Invalid CSV is flagged with a clear error before anything is converted. Common CSV problems to check are a consistent column count per row and proper quoting of fields that contain commas. Starting from clean input keeps the generated TypeScript accurate.

Is my CSV data private?

Yes. The entire CSV-to-TypeScript conversion runs locally in your browser in JavaScript — your CSV is never uploaded, logged or stored. That matters when the data is something like spreadsheet import/export, which should not leave your machine.

Where can I use the TypeScript output?

The generated TypeScript is ready for typed API clients, React/Next.js props and shared front/back types. Copy or download it and drop it straight into your codebase.

🎓 Pro Tips

  • Tip 1: Validate or format your CSV first (the Validate / Format buttons) so the converter works from clean, RFC 4180-conformant input.
  • Tip 2: Give the tool a representative CSV sample — optional fields are only detected from the keys actually present, so include them if they matter.
  • Tip 3: Authoritative reference for the input format: RFC 4180 — https://www.rfc-editor.org/rfc/rfc4180.
  • Tip 4: For the output, follow the TypeScript Handbook (https://www.typescriptlang.org/docs/) conventions in your codebase.

What Is CSV to TypeScript Conversion?

CSV to TypeScript conversion turns the columns of a CSV file into a typed interface describing one row of data. Each header becomes a property, and the converter infers the field type from the column values — a column of whole numbers becomes number, true/false becomes boolean, and anything else stays string. This gives you a ready-to-use type for loading CSV data into a typed codebase, instead of treating every field as a raw string.

How Type Inference Works

CSV itself carries no type information — every cell is text. To produce a professional interface, this tool scans all rows of each column and picks the narrowest type that fits the whole column:

  • number — every non-empty value is numeric (integer or decimal).
  • boolean — every value is true or false (any case).
  • string — the fallback for mixed, text, or empty columns.

Inference follows the same data-driven approach used by tools like quicktype, and the output follows the TypeScript interface syntax.

How to Use the CSV to TypeScript Converter

  • Paste CSV with a header row into the input, or load the example.
  • Click Convert to TypeScript to generate the interface.
  • Copy the result and drop it into your .ts file.

Common Use Cases

Type a CSV import in a Node or front-end project, scaffold a row model for a data-loading script, generate fixtures for tests, or quickly understand the shape of an unfamiliar spreadsheet — all without uploading your data anywhere.

Frequently Asked Questions

Does it detect numbers and booleans, or is everything a string?

It detects types. The converter checks every value in a column and emits number or boolean when the whole column qualifies; otherwise the field is string.

Does the output represent one row or the whole file?

One row. The interface describes a single record; in your code you would type the parsed CSV as an array of that interface (e.g. Row[]).

What if a column mixes numbers and text?

Mixed columns fall back to string, which is the safe, lossless choice — you can refine the type by hand afterwards.

Is my CSV uploaded to a server?

No. Conversion runs entirely in your browser — your data never leaves your device.