HTTP 503 Service Unavailable
The server is temporarily unable to handle the request due to maintenance or overload.
Service Unavailable
The server is temporarily unable to handle the request due to maintenance or overload.
What Causes HTTP 503?
- Server is undergoing scheduled maintenance
- Traffic spike causing resource exhaustion
- Application scaling delayed under load
- Database or cache service is down
- Deployment or restart in progress
Code Examples
See how HTTP 503 responses look in different programming languages and tools.
curl -X GET https://api.example.com/resource
# Response: 503 Service Unavailable
# Retry-After: 120How to Fix HTTP 503
- Check the Retry-After header and wait before retrying
- Implement health checks to detect service availability
- Set up auto-scaling to handle traffic spikes
- Use a load balancer with proper health check configuration
- Monitor with our API uptime monitoring tool
Related Status Codes
The server encountered an unexpected condition that prevented it from fulfilling the request.
The server received an invalid response from an upstream server while acting as a gateway.
The server did not receive a timely response from an upstream server while acting as a gateway.
Rate limit exceeded. The client has sent too many requests in a given time period.
The request was malformed or invalid. The server cannot process it.
Test Your APIs
Frequently Asked Questions
What does HTTP 503 mean?
The server is temporarily unable to handle the request due to maintenance or overload.
What causes HTTP 503?
Server is undergoing scheduled maintenance. Traffic spike causing resource exhaustion. Application scaling delayed under load. Database or cache service is down. Deployment or restart in progress
How to fix HTTP 503?
Check the Retry-After header and wait before retrying. Implement health checks to detect service availability. Set up auto-scaling to handle traffic spikes. Use a load balancer with proper health check configuration. Monitor with our API uptime monitoring tool