Is my sample data sent to Google or any server?

No. The schema is inferred entirely in your browser with JavaScript. Your JSON is never uploaded, so you can safely paste production samples that contain sensitive fields.

What schema format does it produce?

It emits the JSON array format that bq load --schema accepts. Each field has a name, a type such as STRING, INTEGER, FLOAT, BOOLEAN or RECORD, and a mode of REQUIRED, NULLABLE or REPEATED.

How are nested objects and arrays mapped?

Nested objects become RECORD fields, arrays become REPEATED fields, and a null value marks a field NULLABLE. The root of your sample must be an object or an array of objects.

JSON to BigQuery Schema Converter

JSON to BigQuery Schema Converter — Free Online Tool

Generate a BigQuery table schema from sample JSON instantly in your browser. Free and private: your data never leaves your device.

Instant Private Zero cookies

Indentation

JSON input

BigQuery output

Why generate a BigQuery schema from JSON?

Hand-writing a BigQuery table schema for a deeply nested payload is tedious and easy to get wrong. Paste a representative JSON sample above and get a ready-to-load schema in an instant, with types and modes inferred from the actual data you provide.

How it works

The converter inspects your JSON locally and builds the schema array that bq load --schema expects. Scalars are mapped to STRING, INTEGER, FLOAT or BOOLEAN, nested objects become RECORD fields with their own sub-fields, and arrays are marked REPEATED. A null value flags a field as NULLABLE, while present values default to REQUIRED. Everything runs client-side, so nothing ever leaves your machine.

Frequently asked questions

Is my sample data sent to Google or any server?: No. The schema is inferred entirely in your browser with JavaScript. Your JSON is never uploaded, so you can safely paste production samples that contain sensitive fields.
What schema format does it produce?: It emits the JSON array format that bq load --schema accepts. Each field has a name, a type such as STRING, INTEGER, FLOAT, BOOLEAN or RECORD, and a mode of REQUIRED, NULLABLE or REPEATED.
How are nested objects and arrays mapped?: Nested objects become RECORD fields, arrays become REPEATED fields, and a null value marks a field NULLABLE. The root of your sample must be an object or an array of objects.