418 - I'm a Teapot
HTTP 418 I'm a Teapot comes from the HTCPCP joke protocol (RFC 2324) and is non-standard for production APIs.
Last reviewed: February 2, 2026|Editorial standard: source-backed technical guidance
What Does I'm a Teapot Mean?
A non-production status leaked into runtime behavior, which confuses clients and breaks predictable error handling contracts.
Common Causes
- -Debug endpoint intentionally returns teapot status when X-Debug-Teapot header is set in non-production config.
- -Proxy rewrite rule for test brew path leaked into active deployment and routes traffic to joke handler.
- -Integration tests target HTCPCP simulation base URL instead of real API host for that environment.
How to Fix I'm a Teapot
- 1Identify the code path emitting 418 and replace it with a standards-compliant status mapped to real failure semantics.
- 2Remove test/mock middleware, sample routes, or feature flags that accidentally expose joke-protocol behavior in production.
- 3Retest affected clients to ensure new status mapping preserves compatibility and error handling logic.
Step-by-Step Diagnosis for I'm a Teapot
- 1Capture route, deployment version, and middleware chain for requests returning 418.
- 2Trace status generation path to determine whether response originates from app code, proxy rule, or test harness.
- 3Validate documented error contract for the endpoint and select correct replacement status.
- 4Retest with contract tests and client smoke tests to confirm consistent standards-compliant behavior.
Source-of-Status Emission Trace
- -Inspect route handlers and middleware fallbacks (example: debug-only branch returns 418 when unknown enum received).
- -Audit ingress/proxy templates (example: default error map includes 418 from sample config).
Contract and Client Compatibility Validation
- -Map 418 to semantically correct status replacement (example: validation issue should be 400/422, unsupported media should be 415).
- -Verify clients do not rely on accidental 418 behavior from prior buggy releases.
Implementation Examples
curl -i -X GET https://api.example.com/v1/resource
# Response:
# HTTP/1.1 418 I'm a Teapot
# {"error":"I'm a Teapot","code":"418"}const response = await fetch('https://api.example.com/v1/resource', {
method: 'GET',
headers: { 'Accept': 'application/json' }
});
if (response.status === 418) {
console.error("Handle 418 I'm a Teapot");
}import requests
response = requests.get(
'https://api.example.com/v1/resource',
headers={'Accept': 'application/json'}
)
if response.status_code == 418:
print("Handle 418 I'm a Teapot")How to Verify the Fix
- -Repeat affected requests and confirm 418 is replaced by agreed standards-compliant status codes.
- -Validate client SDKs handle replacement statuses without regression.
- -Monitor logs for any residual 418 emissions after deployment.
How to Prevent Recurrence
- -Block non-standard status codes in API linting and CI contract tests.
- -Separate development/test routes from production build artifacts.
- -Add release gates that assert only approved status code sets per endpoint.
Pro Tip
- -maintain an allowlist of status codes per route and fail deployment when runtime traces emit out-of-contract codes.
Decision Support
Compare Guide
HTTP 400 vs 422: Bad Request vs Unprocessable Content
Fix API payload issues faster by using 400 for malformed syntax and 422 for semantic validation failures, so clients correct format before business rules.
Playbook
CORS Error Fix Playbook (Preflight / Origin / Credentials)
Use this playbook to separate browser-enforced cross-origin policy failures from server-side CORS header and route defects and apply strict origin and credential controls safely.
Playbook
Validation Failure Playbook (400 / 422 / INVALID_ARGUMENT)
Use this playbook to separate malformed-request failures from semantic validation failures, then fix request contracts without broad server-side bypasses.
Official References
Provider Context
This guidance is specific to HTTP services. Always validate implementation details against official provider documentation before deploying to production.