JSON to Big Query Schema Converter - Free Online Data Mapping Tool

Online JSON to BigQuery Schema Converter

Simplify your data warehousing workflow with our JSON to BigQuery Schema tool. Manually defining table schemas for Google BigQuery can be time-consuming and prone to errors, especially with nested data. This tool allows you to paste a JSON object or a JSON Schema and instantly generate a valid BigQuery JSON schema file, ready to be used in the Google Cloud Console, CLI, or API.

Why Convert JSON to BigQuery Schema?

Google BigQuery requires a specific schema format to define the structure of your tables. If you are importing large datasets, getting the schema right is critical for data integrity and query performance.

Automate Table Definitions

Whether you are dealing with flat files or deeply nested JSON records, our tool analyzes the data types and structures to create a production-ready schema. This eliminates the need to manually write long arrays of name, type, and mode fields.

Handle Complex Nested Data

BigQuery supports RECORD (struct) and REPEATED (array) modes. Our converter intelligently identifies these structures in your JSON, mapping them to the correct BigQuery nested types so your relational data remains perfectly organized.

Key Features of Our Converter

Our tool is designed to meet the requirements of modern data engineering pipelines on GCP.

1. Intelligent Type Detection

The converter automatically maps standard JSON types to BigQuery's data types:

• string → STRING

• number (integer) → INTEGER / INT64

• number (decimal) → FLOAT64 / NUMERIC

• boolean → BOOL

• ISO 8601 strings → TIMESTAMP or DATE

2. Support for Mode Detection

Our engine recognizes the difference between single objects and arrays. It automatically assigns the REQUIRED, NULLABLE, or REPEATED mode based on your JSON Schema constraints or the presence of arrays in your sample data.

3. Ready-to-Use Output Format

The output is generated as a standard JSON array that BigQuery expects. You can copy this directly into the "Edit as Text" section when creating a table in the BigQuery UI or save it as a .json file for the bq load command.

How to Convert JSON to BigQuery

1. Input your Data: Paste a sample JSON object or a valid JSON Schema into the input box.

2. Analyze: The tool instantly parses the structure and identifies the fields.

3. Generate: View the generated BigQuery schema in the output window.

4. Copy & Deploy: Use the "Copy" button to take the schema and apply it to your Google Cloud project.

Technical Mapping: JSON vs. BigQuery Types

Dealing with Nulls and Optional Fields

In BigQuery, fields are NULLABLE by default. Our converter respects your JSON Schema's required properties to mark specific fields as REQUIRED in BigQuery, helping you maintain strict data quality standards.

Flattening vs. Nesting

By default, this tool preserves the nested structure of your JSON by using the RECORD type. This is the recommended approach for BigQuery to take advantage of its powerful analytical capabilities on semi-structured data.

Frequently Asked Questions (FAQ)

Can I use the output with the bq command-line tool?

Yes! Simply save the output as schema.json and use it in your command: bq make --schema schema.json mydataset.mytable

Does this tool support BigQuery's GEOGRAPHY or BYTES types?

If your JSON Schema specifies these formats or if the sample data follows specific patterns, the tool will attempt to map them. However, you can always manually edit the output for highly specific data types.

Is my data uploaded to any server?

No. All conversion and data analysis are performed locally in your browser using JavaScript. Your sensitive data structures never leave your machine.