What is the difference between REST and SOAP APIs?

REST (Representational State Transfer):

• Type: Architectural style
• Protocol: Uses HTTP/HTTPS
• Data Format: JSON, XML, HTML, plain text
• Performance: Faster, lightweight
• Caching: Supports caching
• Stateless: Each request is independent
• Use Case: Web services, mobile apps, microservices

SOAP (Simple Object Access Protocol):

• Type: Protocol with strict standards
• Protocol: Can use HTTP, SMTP, TCP
• Data Format: Only XML
• Performance: Slower, more overhead
• Caching: No built-in caching
• Stateful: Can maintain state
• Use Case: Enterprise applications, financial services

Key Differences

• Security: REST uses HTTPS/OAuth; SOAP has built-in WS-Security
• Error Handling: REST uses HTTP status codes; SOAP uses fault elements
• Bandwidth: REST requires less bandwidth
• Flexibility: REST is more flexible; SOAP is more rigid

When to Use REST

• Public APIs and web services
• Mobile applications
• Microservices architecture
• When performance is critical

When to Use SOAP

• Enterprise-level security required
• ACID compliance needed
• Formal contracts (WSDL)
• Legacy system integration