In a blog post published on the n8n blog by the n8n team and Yulia Dmitrievna, the most common API authentication methods are explained in detail, along with the pros and cons of each, and how to choose the right approach for securing REST APIs in production environments. API authentication is the process of verifying the identity of a user, application, or service before granting access to protected API resources. Every request to a protected endpoint must present some form of trusted credential, such as a password or an access token, before the API returns data or performs any action. The choice of authentication method determines how you verify identity and how much confidence you can place in it. Stronger controls reduce unauthorized access and credential misuse, but they also introduce token management and maintenance work. On the other hand, simpler methods are faster to implement but may not provide adequate protection for sensitive data. This guide covers different REST API authentication methods and how to choose the most suitable approach for your workflows.
The Difference Between Authentication and Authorization
Authentication verifies who or what is making the API request, whereas authorization determines what that identity is allowed to access or do. For example, an access token may confirm that a specific request came from a particular application (authentication), but the permissions attached to that token determine whether the application can only read customer records or is also authorized to edit and delete them (authorization).
Seven Common API Authentication Methods
Choosing the right authentication method depends on who is calling the API, where the trust boundary lies, and the potential damage if credentials are leaked or compromised.
1. API Keys
API keys work best when one application or service needs to identify itself to another, without the involvement of an end-user granting delegated access. The API issues a unique string, and the caller includes it in the request header or as a query parameter. This method is very common in public APIs that use keys to identify callers and enforce usage limits. API keys are highly simple to implement, but their primary drawback is that they are typically long-lived and provide broad access. If such a key leaks, anyone holding it can impersonate the legitimate application until the key is rotated or revoked. Within the n8n platform, an API key can be stored as a defined credential and automatically injected into the required header or query parameter.
2. Basic Authentication
Basic authentication is suitable for trusted internal integrations or legacy API systems that expect a username and password. In this case, the call only needs to identify itself, and both systems operate within a relatively narrow trust boundary. The client combines the username and password, encodes them in Base64, and sends the result in the "Authorization" header with every request. Because Base64 encoding does not encrypt credentials, basic authentication must run strictly over a secure protocol (HTTPS). The advantage is the simplicity of setup, but the drawback is that a stolen credential remains useful and valid until the password itself is changed in the system.
3. mTLS (Mutual TLS)
For service-to-service integrations requiring a higher level of assurance and security, mTLS provides cryptographic proof tied directly to the connection or request. This method authenticates both the client and the server using TLS certificates. However, managing these additional certificates can increase the operational overhead on the system.
4. HMAC (Hash-Based Message Authentication Code)
HMAC cryptographically signs individual API calls using a shared secret and request data, such as a timestamp or the message payload. This method helps the API detect data tampering and protects against replay attacks. However, HMAC requires managing a shared secret and built-in protections against replay attacks to fully secure requests.
5. OAuth 2.0
The OAuth 2.0 protocol is best suited for workflows where a third-party application needs limited access to a user's resources without obtaining their personal password. The protocol also supports service-to-service connections where the application acts on its own behalf. In the authorization code flow, the user approves specific permissions before the application receives an access token. In contrast, the client credentials flow removes the human user from the process and issues a token directly to the trusted service. The n8n platform handles both authorization code and client credentials flows natively, including token exchange and automatic refreshes for APIs working according to the standard OAuth 2.0 behavior.
6. JWT (JSON Web Token)
JWT is suitable when the API requires a compact, signed token that contains structured information about the user or service. The token and its issuer share a trust relationship through a shared secret or a public-private key pair. It is important to note that JWT is a token format that is often implemented as a layer on top of OAuth 2.0, rather than a standalone authentication protocol. The caller may represent a user or a service, but this does not mean the token inherently delegates access. A JWT token contains claims including the token issuer, intended audience, permissions, and expiration time and date. The API can verify the token's signature without needing to check against a server-side session, making JWT tokens stateless and highly scalable in distributed systems. The drawback is that it is difficult to revoke a valid token before its defined expiration date. Within the n8n platform, you can sign, decode, and verify JWT tokens using the dedicated JWT node, which allows running n8n as a backend service with proper authorization for multiple users, or adding this capability to AI-powered automations to provision or verify credentials.
7. OpenID Connect
Designed for cases where web applications use a user authentication API to verify identity and support single sign-on (SSO), such as "Sign in with Google." The application trusts an external identity provider to authenticate the user instead of managing the user's credentials itself. The OpenID Connect protocol adds an identity layer on top of OAuth 2.0 and returns an ID token containing verified information about the user. The ID token informs the application which user has logged in, while a separate access token determines what the API will allow the application to do. This makes OpenID Connect highly effective for centralized logins and SSO, but it is not a substitute for API authorization.
Best Practices for Securing API Authentication
A secure authentication method can still fail due to reasons such as poorly stored credentials or unvalidated tokens. Adopting the following practices helps mitigate these risks:
- Use HTTPS/TLS for every API request: The TLS protocol encrypts the data passing between the client and the API, protecting passwords, API keys, and tokens from interception. Never send credentials over an unencrypted connection, even for internal services.
- Validate tokens on every request: Do not assume a token is valid just because it worked in the past. Check its signature, expiration time, issuer, intended audience, and required permissions every time the API receives it.
- Plan ahead for token expiration, rotation, and revocation: Use short-lived access tokens as much as possible, and rotate long-lived API keys and client secrets according to a predefined schedule. You must have the capability to revoke credentials immediately in the event of a leak, an employee departure, or when a specific integration no longer requires access.
- Apply permissions and scopes according to the principle of least privilege: Grant each user, application, or service the minimum level of access required to perform their task. Restricted permissions limit the damage a compromised credential can cause.
- Monitor and audit authentication activities: Document successful and failed authentication attempts, token issuance, credential changes, and revocations. Monitor for unusual access patterns, as repeated failures or requests from unexpected locations may indicate credential abuse.
How to Choose the Right API Authentication Method
The right choice for your workflows and integrations depends on the degree of trust between systems, the sensitivity of the exposed resources, and the potential consequences in the event of a breach or credential leak. For example, a low-risk integration might only require reliable identification, whereas access to user data should be subject to tighter permissions, with short-lived tokens and simple, rapid revocation. Choose a method that your company can reliably operate over time. Stronger controls are only necessary if you are capable of ongoing management of token refreshes, credential rotation, and handling issues like authentication failures over time. From a practical perspective, the best authentication method is one that meets the security and lifecycle requirements of the integration without introducing unnecessary maintenance complexity.
Managing API Authentication in n8n
Once you have chosen the appropriate authentication method, the n8n platform handles the setup surrounding it. Every n8n workflow that connects to a protected external API must authenticate, but there is no need to rebuild the authentication logic from scratch each time. You configure the credentials only once and reuse them wherever the workflow needs to connect to that service. This approach keeps secrets separate from the workflow itself and prevents copying API keys or tokens into individual nodes.
For OAuth 2.0 connections, n8n independently manages the authorization flow and performs automatic token refreshes, so workflows continue running even after the original token expires. When there is no dedicated built-in integration in n8n, you can authenticate against a REST API using the HTTP Request node by using Basic Auth, API keys, OAuth 2.0, bearer tokens, or custom headers. n8n encrypts stored credentials, giving you control over how they are shared across different projects.
The platform serves as a secure intermediary for AI agents or coding agents, which often lack secure storage for external service credentials, creating a risk of API key leaks in your automations. n8n allows storing encrypted credentials without exposing them to the AI agents themselves, and creating connected MCP (Model Context Protocol) servers that interact with various services and connect them to a Coding Agent or ChatGPT. In this way, you provide your system with a single API key without having to store multiple keys in plain text or upload them to external cloud platforms.