---
title: "What are the common authentication methods in REST APIs?"  
description: "What are the common authentication methods in REST APIs?"  
author: "ICSM Computer"  
published: 2025-06-05  
updated: 2025-06-05  
canonical: https://www.mindstick.com/interview/34210/what-are-the-common-authentication-methods-in-rest-apis  
category: "api(s)"  
tags: ["api(s)"]  
reading_time: 5 minutes  

---

# What are the common authentication methods in REST APIs?

Here are the **most common authentication methods used in REST APIs**, along with brief descriptions:

### 1. Basic Authentication

- **How it works**: Sends `username:password` encoded in Base64 via the `Authorization` header.
- **Example**: `Authorization: Basic dXNlcjpwYXNz`
- **Pros**: Simple, widely supported.
- **Cons**: Insecure without HTTPS; credentials are sent with every request.

### 2. Bearer Token Authentication (OAuth 2.0)

- **How it works**: Sends a token (usually a JWT or opaque token) in the `Authorization` header.
- **Example**: `Authorization: Bearer eyJhbGciOi...`
- **Pros**: Secure, stateless, supports token expiration and scopes.
- **Cons**: Requires token issuance and management.

### 3. API Key Authentication

- **How it works**: Sends a static API key with each request (usually in a header, query, or body).
- **Example**: `x-api-key: abc123xyz`
- **Pros**: Easy to implement.
- **Cons**: Harder to manage securely, no user context, no expiration by default.

### 4. JWT (JSON Web Token)

- **How it works**: A signed token that contains claims (user info, roles, etc.), sent via `Authorization: Bearer`.
- **Pros**: Self-contained, stateless, fast validation.
- **Cons**: Tokens can’t be revoked easily without extra mechanisms (e.g., token blacklists).

### 5. OAuth 2.0 with Authorization Code Flow

- **How it works**: Standard for delegated access (e.g., login with Google/Facebook). Client gets a token after user consents.
- **Use case**: Public APIs, third-party app access.
- **Pros**: Very secure; supports access and refresh tokens.
- **Cons**: More complex to implement.

### 6. Digest Authentication

- **How it works**: Sends a hashed username/password instead of plain text.
- **Pros**: More secure than basic auth.
- **Cons**: Deprecated in many modern APIs; rarely used today.

### 7. Mutual TLS (mTLS)

- **How it works**: Both client and server authenticate each other using certificates.
- **Pros**: Very secure, prevents man-in-the-middle attacks.
- **Cons**: Complex setup, less common in public APIs.

### Summary Table

| Method | Secure w/ HTTPS | Stateless | Supports User Roles | Easy to Implement |
| --- | --- | --- | --- | --- |
| Basic Auth | (without HTTPS) | Yes | NO | Yes |
| Bearer Token (JWT) | Yes | Yes | Yes | Yes |
| API Key | (without HTTPS) | Yes | NO | Yes |
| OAuth 2.0 | Yes | Yes | Yes | NO (complex) |
| mTLS | Yes | Yes | NO | NO (complex) |

## Answers

### Answer by ICSM Computer

Here are the **most common authentication methods used in REST APIs**, along with brief descriptions:

### 1. Basic Authentication

- **How it works**: Sends `username:password` encoded in Base64 via the `Authorization` header.
- **Example**: `Authorization: Basic dXNlcjpwYXNz`
- **Pros**: Simple, widely supported.
- **Cons**: Insecure without HTTPS; credentials are sent with every request.

### 2. Bearer Token Authentication (OAuth 2.0)

- **How it works**: Sends a token (usually a JWT or opaque token) in the `Authorization` header.
- **Example**: `Authorization: Bearer eyJhbGciOi...`
- **Pros**: Secure, stateless, supports token expiration and scopes.
- **Cons**: Requires token issuance and management.

### 3. API Key Authentication

- **How it works**: Sends a static API key with each request (usually in a header, query, or body).
- **Example**: `x-api-key: abc123xyz`
- **Pros**: Easy to implement.
- **Cons**: Harder to manage securely, no user context, no expiration by default.

### 4. JWT (JSON Web Token)

- **How it works**: A signed token that contains claims (user info, roles, etc.), sent via `Authorization: Bearer`.
- **Pros**: Self-contained, stateless, fast validation.
- **Cons**: Tokens can’t be revoked easily without extra mechanisms (e.g., token blacklists).

### 5. OAuth 2.0 with Authorization Code Flow

- **How it works**: Standard for delegated access (e.g., login with Google/Facebook). Client gets a token after user consents.
- **Use case**: Public APIs, third-party app access.
- **Pros**: Very secure; supports access and refresh tokens.
- **Cons**: More complex to implement.

### 6. Digest Authentication

- **How it works**: Sends a hashed username/password instead of plain text.
- **Pros**: More secure than basic auth.
- **Cons**: Deprecated in many modern APIs; rarely used today.

### 7. Mutual TLS (mTLS)

- **How it works**: Both client and server authenticate each other using certificates.
- **Pros**: Very secure, prevents man-in-the-middle attacks.
- **Cons**: Complex setup, less common in public APIs.

### Summary Table

| Method | Secure w/ HTTPS | Stateless | Supports User Roles | Easy to Implement |
| --- | --- | --- | --- | --- |
| Basic Auth | (without HTTPS) | Yes | NO | Yes |
| Bearer Token (JWT) | Yes | Yes | Yes | Yes |
| API Key | (without HTTPS) | Yes | NO | Yes |
| OAuth 2.0 | Yes | Yes | Yes | NO (complex) |
| mTLS | Yes | Yes | NO | NO (complex) |


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Original Source: https://www.mindstick.com/interview/34210/what-are-the-common-authentication-methods-in-rest-apis

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