REST API Market Data to CSV: Prices to a Table

Most market data APIs answer in JSON. Research code and spreadsheets want a table. Here is the shortest route between them.

Open the API Response to Table

For quant research, the first step is usually a price API, which returns a list of bars or ticks, each with a timestamp and a set of fields, often wrapped in a metadata object. Some give the prices as a list of arrays, some as a list of objects. The first job is to find the list that holds the records and flatten it into columns.

API Response to Table does this for GET endpoints. Enter the address, choose Bearer token, API key in a header or Username and password, and send the request. The records become rows, nested fields become columns named by their path, and if the response has several lists you choose the one you want. Download CSV, Excel, JSON or Parquet.

Then check the file. Look at the first rows and the last rows, confirm the timestamps are in the order and format you expect, and keep symbols as text. Run the Data Profiler to count blanks and duplicate timestamps. A response can be cut by a page limit, so compare the row count with what the API documentation says you should get, and request the next page if there is one.

Mind the limits. Only GET requests over https are supported, so an API that needs a POST body will not work. The request goes from your browser straight to the API, so an API that blocks browser calls (CORS) will be refused. Use a read-only key where possible, and respect the provider rate limits and licence terms. This is about moving data between formats and is not investment advice.

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. Enter the endpoint and your authentication, then click Send request.
  3. Pick the list that holds the bars and check the columns.
  4. Download CSV or Parquet and check the row count.

When to use the API Response to Table

  • Save a price history from an API as CSV
  • Check what a market data endpoint returns
  • Turn tick or bar data into Parquet for research
  • Prepare a sample for a colleague

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: Compare the row count with the number of bars you expected. A page limit can silently cut a long history.