Confused by the whole API key vs token debate? Don’t be! We’re here to walk you through the differences between these two authentication modes.
What are API keys and tokens?
If you’re looking at API auth methods, understanding the differences between API keys and API tokens is crucial. Let’s start with a quick API key definition.
Defining API keys
An API key is an alphanumeric string of code that an API server can use to identify an API caller (usually an app, device or software module) and validate the caller’s authenticity. Its primary purpose is to identify the caller and grant access.
Defining API tokens
An API token – one of the most common forms of which is a bearer token – is also code-based but is usually more complex than an API key. It contains information about a user (the bearer) and their permissions, meaning an API server can not only authenticate the user but also validate their specific access privileges.
Core components of each
An API key is a long-lived means of providing access to an API. Developers can use it to:
- Control who accesses their API
- Monitor usage
- Put a rate limiting strategy in place
- Identify APIs that are stopping an app working properly
An API token is shorter-lived and dynamically generated, either as part of an authentication flow or in response to a specific system action. It carries more data about the user and what they are permitted to do.
Quick comparison overview
In summary, an API key is used to identify and authorize the API caller, while an API token helps identify a user and validate their specific permissions. An API key is handy for public data and third-party access use cases, while API token authentication is better for temporary user authentication and sessions (including multi-factor authentication, fine-grained access control and as part of OAuth flows).
Key differences and characteristics
With API key meaning taken care of, let’s look at the differences between a key and an API security token.
Generation methods and lifecycle
An API key is a static alphanumeric string that tends to be long-lived (though it can be set to expire). It is usually generated via an admin interface or developer portal. The image below shows how to generate an API key using Tyk Dashboard. You can also watch how to generate an API key in this video.
An API token is generated dynamically as part of an auth flow or specific action. Tokens tend to be short-lived, easy to revoke and easy to refresh. You can enable bearer tokens as part of your API definition for easy generation. The image below shows how to do this in Tyk Dashboard.
Structure and format
We notice clear differences when looking at API key vs bearer token (or other kind of API token) structure and format. An API key is simply an alphanumeric string. An API token is more structured, often containing a header, payload and signature.
Scope and permissions
Bearer token vs API key scopes and permissions are distinctly different. An API key’s scope is to identify an API caller and permit them access. An API token’s scope is broader, with permissions linked to user roles. A token’s scope may also cover multiple APIs, such as in the case of single sign-on (SSO) tokens granting users permission to access numerous domains.
Duration and expiration
API keys have longer durations than API tokens, though both can be set to expire. Keys usually remain in place until rotated or revoked, while access tokens usually expire after a brief time period.
Storage and management
The way in which you store and manage API keys and tokens has important security implications. Keeping API keys out of code repositories and application source trees is essential for protecting against unauthorized access. Secure storage solutions can include dedicated secrets management services and environment variables, along with encrypted databases.
For API security token storage, browser in-memory or local storage solutions can both work, depending on your application.
Security implications
There’s plenty to think about when it comes to API security best practices. After all, a single misstep has the potential to cause major reputational and financial loss. For API key vs token security, there are numerous considerations to keep in mind.
Security considerations for API keys
API keys grant broad access to your APIs/data. As such, defending against compromise is paramount. Your observability strategy plays a crucial role in this defense, so if you’re not yet familiar with what OpenTelemetry is, now could be a good time to learn! And remember that API keys are there to identify callers – they should never be used as a standalone security measure, but as one element of a comprehensive security solution.
Other security considerations for API keys include periodic rotation, ensuring you restrict which keys are usable for which APIs and remembering to delete any keys that are no longer needed.
Security considerations for tokens
As API tokens are used to control access, they are more security-focused than API keys, with more granular security controls.
Their short-lived nature and the fact they are easy to revoke, combined with the fact that each token only defines a single user’s permissions, means that compromised tokens are usually less worrying than a compromised API key.
Risk assessment
What is API token and API key risk assessment focused on? Well, as with all areas of API security risk assessment, it’s important to consider how to protect the integrity and confidentiality of your APIs and data, while also supporting high availability and reliable performance.
When looking at elements of risk, be sure to consider your full authentication and authorization flow, including encryption, error handling, rate limiting and input validation. As always, remember to consider security in terms of both data at rest and data in transit.
Handling compromised credentials
If an API key has been compromised, you will need to revoke it and create a new key to use in its place. The same applies with an API security token. While this takes care of the situation in technical terms, you’ll also need to dig into the impact of the compromised credentials and follow any relevant regulatory procedures in terms of reporting the breach.
Best practices for secure storage
API key vs access token storage is an important consideration. As we touched on above, secure storage is your best defense against unauthorized access. Using environment variables or dedicated secrets management services is good practice for API keys, while browser local storage and browser in-memory can work for secure token storage.
In terms of best secure storage best practices, remember never to add sensitive data to the payload and never to send anything over non-HTTPS connections. Rotate API keys periodically and ensure tokens have a set expiration time. Take care of the people element too, with regular security training for your team.
When to use API keys
API keys are an excellent way to confirm an API caller’s identity, meaning they have numerous use cases.
Ideal use cases
The ideal use case for an API key is a scenario in which you need to grant long-lived access to the entirety of your API and want to identify the applications that are calling it. Example use cases include:
Server-to-server communication
API keys can ensure communication only flows between permitted servers and apps. If the API server doesn’t recognize a key, it won’t grant access.
Third-party integrations
When you want to encourage third-party integrations of your API while retaining the ability to monitor usage (with rate limiting and monetization in mind) and troubleshoot integrations.
Public API access
API keys are often used to provide access to public data (such as weather APIs), making this an important use case for an API key (vs token).
Limitations and considerations
Remember that an API key is not a standalone security solution and should not be used as such. It is for use as part of your wider API security strategy.
When to use tokens
Using an API token vs API key also has clear use cases.
Authentication scenarios
API tokens provide a security-focused means of authenticating users for your apps, websites and services. By granting temporary access to resources and defining the user’s permissions, they can enable the user to achieve what they need while only allowing access to the data you choose.
User sessions
You can use token expiration as part of your security strategy and to help users keep their accounts safe. As you can define the expiration period, you can decide what best practice looks like within the context of your app or service, ensuring user sessions last an appropriate amount of time for your specific scenario.
Single sign-on (SSO)
Using tokens for SSO makes life easier for you and your users. You can use strong authentication methods and help prevent the reuse of passwords across different services, thus boosting security. SSO can also make account administration easier while enhancing the user experience.
OAuth and JWT implementation
JSON web tokens (JWTs) are often used for stateless authentication. Many OAuth implementations use JWTs, combining the robustness of OAuth with JWTs’ secure encoding of user information.
Benefits and trade-offs
API tokens can deliver fine-grained access control as part of your authentication flow. The are more secure than API keys and suit a variety of use cases, as we’ve seen above.
Conclusion
We’ve looked in detail at the whole API key vs token debate, covering everything from key differences to security and use cases. You can now move forward with confidence in terms of how best to implement and manage your auth flows.
Next steps
We’ve touched on OAuth as part of the whole API token vs API key debate. Why not explore in detail what OAuth is and how you can benefit from embracing it?
