This tutorial shows you how to authenticate with FinFeedAPI using your API key and make your first successful request.

The authentication method is the same across all FinFeedAPI products — the only thing that changes is the base URL of the product you are using.

By the end of this guide, you will know how to:

• Authenticate using your API key
• Send a request to a FinFeedAPI endpoint
• Verify that your connection is working.

What you need before you start

• ✅ A FinFeedAPI API Key
• ✅ Any HTTP client:
  • Terminal (curl)
  • Postman / Insomnia
  • Browser (for simple GET requests)

Step 1 — Choose the FinFeedAPI product you want to access

FinFeedAPI provides several APIs, each with its own base URL:

• Stock API: https://api-historical.stock.finfeedapi.com
• SEC API: https://api.sec.finfeedapi.com
• Currencies API:
  • https://api-realtime.fx.finfeedapi.com
  • https://api-historical.fx.finfeedapi.com
• Prediction Markets: https://api.prediction-markets.finfeedapi.com/

Use the base URL provided in the product documentation.

Once you know the correct base URL, you can begin making requests.

Step 2 — Authenticate using your API key

FinFeedAPI allows you to authenticate your requests using your API key.

There are two common ways to pass the API key.

Note: These are just example authentication methods for getting started. FinFeedAPI may support additional authentication options depending on the product. Refer to the documentation for each API product to explore all available authentication methods.

Option A — Query parameter (easiest to start)

Format

1?apikey=YOUR_API_KEY

Example: Prediction Markets - list supported exchanges

1curl"https://api.prediction-markets.finfeedapi.com/v1/exchanges?apikey=YOUR_API_KEY"

Example: Currencies API - list assets

1curl"https://api-realtime.fx.finfeedapi.com/v1/assets?apikey=YOUR_API_KEY"

Option B — Authorization header (better for production)

You can also pass the API key in the request header.

Header format

1Authorization: YOUR_API_KEY

Example: Stock API - List of exchanges

1curl"https://api-historical.stock.finfeedapi.com/v1/exchanges" \
2  -H"Authorization: YOUR_API_KEY" \
3  -H"Accept: application/json"

Step 3 — Send your first API request

A good first request is a simple GET endpoint that returns a list of available resources.

For example, the Prediction Markets API provides an endpoint that lists supported exchanges.

Example request

1curl "https://api.prediction-markets.finfeedapi.com/v1/exchanges?apikey=YOUR_API_KEY"

Step 4 — Verify the response

If authentication is successful, the API will return a JSON response.

Example:

1[ 
2  { 
3    "exchange_id": "POLYMARKET",
4    "market_name_institution_description": "Polymarket" 
5  }, 
6  { 
7  "exchange_id": "KALSHI",
8  "market_name_institution_description": "Kalshi"
9  }
10]

Receiving a response like this confirms that:

• your API key is valid
• your request is authenticated
• you are successfully connected to FinFeedAPI

Troubleshooting

• 401 / 403 Unauthorized - If you’ve just created a new API key, allow up to 10 minutes for it to propagate. Also, confirm the API key is correctly formatted and that your organization has available credits.
• Empty or unexpected results - Verify the exchange_id is valid and start with small pagination values (e.g. limit=5&page=1) to confirm data is returned.

🎉 Congratulations!

You’ve successfully authenticated and made your first FinFeedAPI request.

From here, you can begin exploring the different APIs available in FinFeed, such as retrieving market data, accessing prediction markets, or integrating FinFeed data directly into your applications.

Visit the documentation for the specific product you are using to explore additional endpoints, features, and authentication options.

Happy building! 🚀