Skip to content
beginnerPhase ·

PUT

Deep dive into the PUT method for replacing resources.

20m
0 problems
Topic Progress0%

The PUT Method

PUT replaces an entire resource with new data. If the resource doesn't exist, PUT can create it.

PUT Characteristics

PUT /api/users/123 HTTP/1.1
Host: api.example.com
Content-Type: application/json

{
  "name": "Alice Updated",
  "email": "alice.new@example.com",
  "role": "admin"
}

→ Not safe: Modifies server state
→ Idempotent: Same request = same final state
→ Not cacheable by default
→ Has a request body (full resource)

PUT vs POST

Aspect PUT POST
Purpose Replace resource Create resource
Idempotent Yes No
URL Specific (/users/123) Collection (/users)
Body Full resource New resource data
Duplicate Same result Creates duplicates

PUT Examples

# Replace a user
PUT /api/users/123
Content-Type: application/json
{
  "name": "Alice Updated",
  "email": "alice@example.com",
  "role": "superadmin"
}

# Create or replace (idempotent)
PUT /api/config/theme
Content-Type: application/json
{"color": "dark", "font": "monospace"}

PUT Design Best Practices

  1. Client specifies the URL — PUT uses the full resource URL
  2. Send the complete resource — PUT replaces the entire object
  3. Return 200 OK (updated) or 201 Created (new)
  4. Validate the entire resource — All required fields must be present
  5. Handle missing resources — Create or return 404

HTTP Best Practices

Methods

  • GET: Read (safe, idempotent)
  • POST: Create
  • PUT: Replace (idempotent)
  • PATCH: Partial update
  • DELETE: Remove (idempotent)

Headers

  • Content-Type: Body format
  • Cache-Control: Caching rules
  • Authorization: Authentication
  • Accept: Desired response format

Status Codes

  • 2xx: Success
  • 3xx: Redirection
  • 4xx: Client error
  • 5xx: Server error

Key Points

  • Understanding PUT is essential for production systems
  • Always consider scalability and maintainability
  • Test thoroughly before deploying to production
  • Monitor performance and set up alerting

Common Patterns

  1. Validation: Always validate input at the boundary
  2. Error Handling: Use structured error responses
  3. Logging: Log key events for debugging
  4. Testing: Unit, integration, and load tests
  5. Documentation: Keep docs updated with code changes

Practice Problems

0/3solved
Implement PUT

Design and implement a solution for PUT in a backend system. Consider scalability, error handling, and production readiness.

Solution
// PUT implementation
// Key aspects: validation, error handling, logging, testing

public class PUT {
    // Production-ready implementation
}
PUT Edge Cases

Identify and handle edge cases for PUT. What happens under high load, with invalid input, or during failures?

Solution
// Edge case handling:
// 1. Null/empty input -> validation
// 2. High load -> rate limiting, queuing
// 3. Failures -> retries, circuit breaker
// 4. Concurrent access -> locks, idempotency
PUT Testing Strategy

Write a testing strategy for PUT. Include unit tests, integration tests, and performance tests.

Solution
// Test plan:
// - Unit: 80% coverage target
// - Integration: API contracts
// - Performance: latency, throughput
// - Chaos: failure injection

Quiz

1. What is the key difference between PUT and PATCH?

Question 1 options

2. Why is PUT idempotent?

Question 2 options

3. What is the primary purpose of PUT?

Question 3 options

4. What is a common mistake when implementing PUT?

Question 4 options

Flashcards

Question

What does PUT do?

Click to reveal answer

Answer

Replaces an entire resource — idempotent, not safe

Question

PUT vs PATCH?

Click to reveal answer

Answer

PUT replaces entire resource; PATCH updates specific fields

Question

What is PUT?

Click to reveal answer

Answer

PUT is a key concept in backend development.

Question

When to use PUT?

Click to reveal answer

Answer

Use PUT when building production systems that require reliability, scalability, and maintainability.

Question

PUT best practices

Click to reveal answer

Answer

Follow SOLID principles, write clean code, test thoroughly, document decisions, and monitor in production.

Revision Notes

Key Takeaways

  • 1.PUT replaces the entire resource
  • 2.PUT is idempotent — same request = same result
  • 3.Client specifies the URL for PUT
  • 4.PUT vs PATCH: full replace vs partial update

Interview Tips

  • •Know when to use PUT vs PATCH
  • •Understand idempotency of PUT

Cheat Sheet

PUT

  • Purpose: Replace entire resource
  • Properties: Idempotent, Not safe
  • Body: Complete resource (all fields required)
  • vs PATCH: PUT = full replace, PATCH = partial update