An API key is one of the simplest and most common ways to control access to an API. Think of it as a personalized ID badge for software. Whenever an app wants data from an API, it includes its API key in the request. If the key is valid, the API opens the door and sends back the information.
API keys help API providers understand who is calling their system. They can track usage, set rate limits, block suspicious behavior, and keep sensitive data protected. Even though an API key is just a string of characters, it carries a lot of responsibility—it's the first checkpoint that keeps the system secure.
Developers use API keys because they’re easy to set up and easy to automate. Once the key is stored safely inside an app or backend system, it can be used again and again without any manual steps. The only rule: it must be kept private. If someone else gains access to your API key, they can send requests as if they were you.
API keys protect APIs from unauthorized use and help companies manage access to valuable or sensitive data. For financial data, where accuracy and security are critical, API keys are essential.
You attach the key to each API request—usually in the header or as a query parameter. The API checks the key, verifies the user, and sends back the requested data.
If someone steals your API key, they can access the API as if they were you. Most platforms let you rotate (replace) the key immediately to block unauthorized usage.
A fintech app wants to show exchange rates. To do that, it sends a request to a currency API along with its API key. The key tells the server, “This request is coming from an approved user,” and the API returns the latest FX data.
FinFeedAPI uses API keys to secure access to all of its data products—Stock API, Currency API, SEC API, Prediction Market API, and Flat Files S3 API. Each request must include a valid key, ensuring your data remains protected and your usage stays organized and trackable.
