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How to Use API Keys Securely in Postman

How to use API Keys Securely in Postman

Data security has become one of the biggest responsibilities of businesses and developers in our age. Many applications retrieve, store, and display users’ personal information exclusively for the respective user. Today’s software applications actively carry this data with APIs. Authentication tokens and API keys play a crucial role in realizing API security today. So what is an API key?

API key identifies the security. API keys serve as a specialized code that actively safeguards an API server against unauthorized users. With this code, developers and businesses maximize the security of the APIs they provide data to. In this article, we will talk about when an API key can be used. Then, we will explain how an API key that should not be shared with anyone for application security can be used securely in the Postman application.

When to Use an API Key?

There can be many purposes for using an API key in applications. In this section, we will list some of these purposes:

  • Authentication: API keys authenticate users or applications that intend to access the API server. The API provider can use the API key when it wants to check the authorization of external users.
  • API Quotas and Limitations: API keys provide users with the ability to impose limitations and quotas on API usage. This means that the API provider can effectively restrict the number or speed of requests made within a specific time frame for each API key. Consequently, API providers in need of these limitations and quotas can readily utilize API keys as a solution to manage and control their API resources effectively.
  • API Analysis and Monitoring: API keys allow users or applications to effectively track and analyze API usage. Each API key facilitates the monitoring of how the API is utilized and enables the evaluation of performance. This includes collecting essential usage statistics, response times, errors, and other performance metrics. As a result, API providers can leverage these valuable insights derived from API key analytics to inform their growth and market strategies.

Learn in detail why and when to use an API key!

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Tip for Using API Keys in Postman

It is very important to use and protect API keys securely. In this section, we will talk about how developers can use API keys securely in the Postman application, where they perform API testing.

Keep API keys private

Developers should consider API keys as sensitive information. Thus, they should avoid sharing these API keys with anyone. Moreover, they should not share API keys publicly in any document or content.

They must also be used discreetly in the Postman application. In the Postman application, developers can keep sensitive information, such as API keys, in an environment with the ‘secret’ type.

environment variables section for keeping api keys in the postman

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Use environment variables

Developers can define environment variables in Postman, enabling the storage of sensitive information like API keys. Also, In Postman, developers can use variables such as the API keys stored in environment variables by referencing them with their variable names. So, developers do not have to statically add the API key to every request.

using the api key in postman from the environment

Use environment variables in code

In the previous topic, we discussed the utilization of environment variables in API requests. Another area where the developers should use the API key securely is the ‘Pre-request Script’ and ‘Tests’ areas in Postman. Adding API keys statically in codes written to these fields can create a security vulnerability. Therefore, developers need to obtain the API key value from environment variables with the code ‘pm.environment.get()‘.

getting the api key with a line of code

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Do not use the specific API key

It’s important to note that relying on a single API key for an extended period can pose security risks. To mitigate these risks, developers should periodically regenerate the API keys utilized in their Postman applications. By regularly creating new API keys, the overall security of the application is enhanced. As a result, shifting to new API keys at regular intervals makes it increasingly challenging for unauthorized users to acquire and exploit them.


As a result, API keys are one of the most important security methods of today in order not to share the data carried by the APIs with unauthorized users. However, integrating API keys with API providers does not provide security on its own. API key owners should keep these API keys in secure environments and not share them with anyone. Especially, it is very important to keep API keys with environment variables in Postman, which is the API testing tool where API tests are most frequently performed, and to store and use them with the ‘secret’ type.

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Q: What is an API Key?

A: API (Application Programming Interface) keys serve as secret credentials for applications to access specific APIs. These keys play a crucial role in ensuring the proper access of APIs by applications. Additionally, API keys hold significant importance in terms of user security, as they enable user authentication and authorization.

Q: What are the Benefits of Using an API Secret Key on an API Server?

A: There are many benefits to using a secret API key to perform an API request on an API server. Some of these are as follows:

  • Protect Sensitive Data
  • Authentication
  • Usage Restrictions
  • Identify Application Traffic
  • Statistics and Analysis
  • Pricing and Income Tracking

Q: Can I Test API Keys in Postman?

A: Yes, you can. Postman, being a comprehensive and well-equipped API testing tool, allows you to do that. Moreover, it provides an easy-to-use and rich interface. With Postman, users can effortlessly test their APIs using API keys in just a few simple steps.

Q: Are API Keys Secure?

A: Yes they are. API keys are very secure like authentication tokens, which is another API security method today. API keys prevent non-authorized users of target APIs from obtaining data via an API call.

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I am a software developer who loves coding, learning new technologies, improving myself and researching.
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