Flatten a Financial API Response to Parquet

Parquet is a flat, typed file, so a nested financial API response has to be flattened to fit. Done well, it gives you a compact dataset for analysis.

Open the API Response to Table

Open API Response to Table. Either enter the endpoint and your sign-in (Bearer token, API key in a header, or username and password) and click Send request, or paste the JSON you already have. If the response holds more than one list, pick the list that has your records.

Look at how the columns are named. Nested objects become columns named by their path, so a field company.sector inside each record gives a column called company.sector. Records that lack a field get an empty cell, so a column with many blanks usually means the field is optional. The Data Profiler counts them.

Download Parquet. Each record is one row and every flattened field is a column with a type. Set the types before you export: amounts as numbers, dates as dates, ids as text. If the dates arrive as strings, fix them in Data Transformation first.

The file is usually much smaller than the same data as CSV or JSON, and DuckDB, pandas, Polars and Spark read it directly. Read it back as CSV with the Format Converter and compare the first and last rows with the response.

Everything runs in your browser and nothing is uploaded.

Open the API Response to Table

Related tool pages

  • JSON API Response to CSV: Turn the JSON from an API into a CSV file. Nested fields become columns and you pick which list to use. Free, in your browser, with an optional token.

How to use the API Response to Table: step by step

  1. Open API Response to Table.
  2. Send the request or paste the JSON.
  3. Check the column names and fix types if needed.
  4. Download Parquet and read it back.

When to use the API Response to Table

  • Build an analysis dataset from an API
  • Store snapshots compactly
  • Load a response into DuckDB or pandas
  • Keep column types in a shared file

Example

Input: GET https://api.example.com/users + Bearer token

Output: id,name,address.city 1,Ada,London

Frequently asked questions

How does the token work?

Choose Bearer token, API key in a header, or username and password, and paste the value. It is sent only to the API you call, kept in memory, and never saved or written to Data Lineage.

What if the API blocks the request?

Some APIs do not allow calls from other websites (CORS), so the browser blocks the request. Use an API that allows browser access, or ask its owner to enable CORS.

What happens to nested fields?

Nested objects are flattened into columns such as address.city. If the response has several lists, you can choose which one becomes the table.

Is it safe to use a token in API Response to Table?

Your token goes only to the API you call, straight from your browser. Data Utility never receives it or the response. It is kept in memory for that request, not saved, and not written to Data Lineage. Use a token with read-only access when you can.

Tip: Set date and number types before you export. Parquet keeps the type you give it.