API Gateway WebSocket API versus ALB

19 Nov 2025

Learn how API Gateway WebSocket API differs from ALB.

	API Gateway WebSocket API	ALB
Type	Websocket	REST API
HTTPS/TLS	✅	✅
Backends	✅ Lambda ✅ Public endpoint ✅ Private endpoint ✅ AWS Service APIs	✅ Lambda ❌ Public endpoint ✅ Private endpoint ❌ AWS Service APIs
Costs	💰	💰💰
Maturity	⭐️⭐️⭐️⭐️	⭐️⭐️⭐️⭐️
Authentication	✅ IAM ❌ API Key ❌ OpenID Connect ❌ SAML ❌ Social ✅ Custom	❌ IAM ❌ API Key ✅ OpenID Connect ✅ SAML ✅ Social ❌ Custom
Tenant-based Throttling	❌	❌
Request Validation	✅	❌
Req./Res. Transformation	✅	❌
Endpoints	✅ Public ❌ Private	✅ Public ✅ Private
WAF	❌	✅

Further reading