How does it decide whether a value is a string or a number?

Each value is type-inferred. A value that parses as a finite number becomes a bare GraphQL number, true/false becomes a boolean, an empty cell becomes null, and everything else is emitted as a double-quoted string with internal quotes and backslashes escaped.

Can it handle quoted CSV fields with commas inside?

Yes. The parser follows RFC 4180 rules — fields wrapped in double quotes may contain commas, newlines and escaped double quotes ("") — so addresses and descriptions are split correctly.

How are multiple rows combined?

You can output each row as its own named operation, or alias them into a single mutation document (row0, row1, …) so the whole batch runs in one request. The tool labels each alias for readability.

Does it generate the variables block or inline values?

It inlines the values directly as mutation arguments, which is the quickest form for seeding and testing. You can adapt it to variables afterwards if you prefer parameterised operations.

Is my CSV uploaded anywhere?

No. Parsing and code generation run entirely in your browser, so customer records or seed data in the CSV never leave your device.

CSV to GraphQL Mutation Generator

When you need to seed a GraphQL API or import a spreadsheet of records, writing one mutation per row by hand is slow. This tool reads your CSV and emits a GraphQL document with one createX call per row, inferring the right scalar type for every value — so strings are quoted, numbers and booleans are bare, and empty cells become null.

How it works

Parse the CSV with an RFC 4180 parser that respects quoted fields containing commas, newlines and escaped "" quotes. The first row supplies the field names.
Infer each value’s type so the GraphQL is syntactically correct:
- empty → null
- true / false (case-insensitive) → boolean
- a finite number → numeric literal
- anything else → a double-quoted string, with " and \ escaped
Emit the mutation. Each row becomes mutationField(arg1: value1, arg2: value2) { id }. You can output one operation per row, or alias all rows into a single document (row0: createUser(...) { id }) so the batch runs in one request.

mutation Seed {
  row0: createUser(name: "Ada", age: 36, active: true) { id }
  row1: createUser(name: "Linus", age: 54, active: false) { id }
}

Tips and notes

Header names are used verbatim as argument names — make sure they match your schema’s input fields (or rename the CSV header row).
Quote a numeric-looking value in the CSV (e.g. a postcode or phone number) by wrapping it in "…" if you want it kept as a string; otherwise it is inferred as a number.
The selection set defaults to { id }; change it after generation if your mutation returns a different shape.
Everything runs locally, so the CSV’s contents stay on your device.