What are authentication APIs?

Authentication APIs provide services for verifying user identity, managing OAuth flows, implementing single sign-on (SSO), and issuing tokens such as JWTs for secure application access.

What is the difference between OAuth and API key authentication?

OAuth is a delegated authorization framework that allows users to grant third-party apps limited access to their accounts without sharing passwords. API keys are simpler static credentials used for server-to-server communication.

Which authentication API should I use for my app?

For most web apps, Auth0 or Okta provide managed identity platforms with free tiers. For simpler needs, a JWT-based solution or social OAuth via Google or GitHub may be sufficient.

Authentication APIs

Authentication and authorization services

7 APIs in this category

Showing 7 of 7 APIs

Auth0

Flexible authentication and authorization platform for applications

Auth: apiKey HTTPS CORS: Yes

GetOTP

API to quickly implement one-time password (OTP) verification flow

Auth: apiKey HTTPS CORS: No

Micro User Service

User management and authentication microservice API

Auth: apiKey HTTPS CORS: No

MojoAuth

Passwordless authentication platform for secure and seamless login

Auth: apiKey HTTPS CORS: Yes

SAWO Labs

Passwordless authentication service for fast and secure user login

Auth: apiKey HTTPS CORS: Yes

Stytch

Modern authentication infrastructure for developers and apps

Auth: apiKey HTTPS CORS: No

Warrant

Authorization and access control APIs for your apps

Auth: apiKey HTTPS CORS: Yes

API	Description	Auth	HTTPS	CORS
Auth0	Flexible authentication and authorization platform for applications	apiKey	✓	✓
GetOTP	API to quickly implement one-time password (OTP) verification flow	apiKey	✓	✗
Micro User Service	User management and authentication microservice API	apiKey	✓	✗
MojoAuth	Passwordless authentication platform for secure and seamless login	apiKey	✓	✓
SAWO Labs	Passwordless authentication service for fast and secure user login	apiKey	✓	✓
Stytch	Modern authentication infrastructure for developers and apps	apiKey	✓	✗
Warrant	Authorization and access control APIs for your apps	apiKey	✓	✓

Best Authentication APIs for Developers

An authentication API allows developers to implement secure user login, OAuth social sign-in, multi-factor authentication, and identity management without building these complex systems from scratch. These APIs handle token issuance, session management, and user verification.

CodeHelper's curated authentication API collection includes APIs covering OAuth providers, SSO services, JWT utilities, and identity management platforms.

What to look for in an authentication API

Standards compliance: Look for APIs that support OAuth 2.0 and OpenID Connect for maximum interoperability.
MFA support: Multi-factor authentication options (TOTP, SMS, email) add critical security layers for sensitive apps.
SDK availability: Official SDKs for your language or framework significantly reduce integration time.

How to use this API directory

Browse the curated list of APIs below.
Click any API to visit its documentation.
Check the Auth column to understand what credentials you need.

Whether you are building a SaaS login system or a social sign-in feature, this free curated API directory saves you hours of research.

Authentication APIs

Auth0

GetOTP

Micro User Service

MojoAuth

SAWO Labs

Stytch

Warrant

Best Authentication APIs for Developers

What to look for in an authentication API

How to use this API directory

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