The quickest REST API health check example is: curl http://127.0.0.1:8080/health. It sends a GET request to a local service on port 8080 and displays the health endpoint response.

curl http://127.0.0.1:8080/health

Expected healthy result:
HTTP status: 200
Body: OK

The official curl manual documents URL-based HTTP requests and response-output options. The command proves that something listening on the local loopback address can answer that route. It does not prove that DNS, TLS, a public gateway, a load balancer, every dependency, or every customer transaction is healthy.

What Is an API Health Check?

An API health check is a lightweight request that helps a machine or operator decide whether an API process is alive, ready for traffic, still starting, or unable to reach an essential dependency. A health check API endpoint is the route that exposes that decision.

The phrase “we can start with just adding a REST endpoint” “current state of the system” Rockset represents a practical search intent: teams often want to begin with a simple endpoint that exposes the current state of the system. It should not be treated as a verified quotation from Rockset. The correct design question is: which state should this endpoint represent, and which automated action will consume it?

Red Hat’s current Quay documentation describes health checks as a way to assess functionality and understand the current state for troubleshooting. That same principle applies broadly: the API health endpoint should represent a clearly defined condition rather than an undefined promise that “everything is fine.”

What a health endpoint can prove

• The process can receive and complete a small HTTP request.
• The instance is ready to accept new traffic.
• Startup initialization has completed.
• A carefully selected required dependency is currently available.
• A load balancer or orchestrator should keep or remove the instance from service.

What it cannot prove by itself

• Every customer workflow succeeds.
• Authorization and tenant isolation are correct.
• Responses do not expose sensitive data.
• The API is free from abuse, scraping, BOLA, replay, or business-logic attacks.
• Public DNS, certificates, CDN, gateway, and routing work from every region.

API Health Check Endpoint Examples

The examples below intentionally include the exact command patterns people search for. Replace ports and paths only after confirming the application’s real configuration.

Core curl examples

GET request notation

GET http://localhost:8080/api/health

Equivalent curl request:
curl http://localhost:8080/api/health

The phrase GET http://localhost:8080/api/health describes the HTTP method and URL. The curl command actually sends that GET request because GET is curl’s default method for a plain URL.

Useful curl output options

Health Endpoint Naming Patterns

Kubernetes currently exposes healthz, livez, and readyz for the API server, and notes that healthz is deprecated there in favor of the more specific endpoints. This does not mean every application must copy Kubernetes exactly; it demonstrates why explicit semantics are more useful than one overloaded route.

REST API Health Check Best Practices

1. Answer one operational question. Decide whether the endpoint represents liveness, readiness, startup, or diagnostics.
2. Keep the request cheap. Avoid large queries, remote fan-out, file scans, expensive model calls, and full business transactions.
3. Return quickly. Use bounded dependency timeouts and make the endpoint higher priority than ordinary work when practical.
4. Use meaningful status codes. Return a successful status when the condition is satisfied and a failure status when it is not.
5. Separate public and detailed responses. Public health should disclose almost nothing; component diagnostics should be protected.
6. Avoid stale caching. Health consumers need current state, not an old successful response.
7. Require repeated failure. A single timeout should not immediately restart a fleet or create an incident.
8. Test from multiple layers. Local, internal, gateway, load-balancer, and external checks answer different questions.
9. Monitor real traffic too. Health endpoints do not replace latency, error, transaction, and security telemetry.
10. Protect the route from abuse. A health endpoint must not become a denial-of-service amplifier.

API health endpoint best practices

The strongest API health endpoint best practices are to keep the machine response small, define ownership, document the expected status, establish timeout and failure thresholds, verify the route through the actual production path, and correlate the result with application metrics.

Health check endpoint best practices

Health check endpoint best practices also include protecting detailed component information, using separate management networks or authentication where necessary, and avoiding credentials, software versions, internal hostnames, stack traces, and customer data in responses.

Health endpoint monitoring pattern

Local liveness check
  → Can the process make progress?

Instance readiness check
  → Should this instance receive new traffic?

Internal service check
  → Can the service be reached through the private route?

Public synthetic check
  → Do DNS, TLS, edge, gateway, routing, and the API endpoint work?

Passive runtime monitoring
  → Are real users seeing latency, errors, abuse, or data exposure?

OWASP’s denial-of-service guidance recommends identifying bottlenecks and testing controls across layers. A healthcheck endpoint should therefore be deliberately low-cost and isolated from expensive work.

Liveness, Readiness, Startup, and Dependency Health

Kubernetes documentation separates liveness, readiness, and startup probes. The distinction is useful even outside Kubernetes because each result should trigger a different action.

See Ammune’s guide to active and passive health monitoring methods for a wider monitoring comparison.

API Health Endpoint Response Examples

Minimal healthy response

HTTP/1.1 200 OK
Cache-Control: no-store
Content-Type: text/plain

OK

Minimal not-ready response

HTTP/1.1 503 Service Unavailable
Cache-Control: no-store
Content-Type: text/plain

NOT READY

Protected structured response

{
  "status": "degraded",
  "checks": {
    "database": "up",
    "queue": "delayed",
    "model_provider": "up"
  },
  "observed_at": "2026-07-30T16:00:00Z"
}

RFC 9110 defines HTTP semantics and status codes including successful and service-unavailable responses. RFC 9111 defines HTTP caching behavior; health responses commonly use a no-store policy so intermediaries do not hide a new failure behind an old success.

Red Hat Quay documents health endpoints that return 200 when healthy and 503 when a deployment problem is detected, providing a current product example of status-driven health behavior.

Current Platform Health Endpoint Examples

n8n health check endpoint

Current n8n documentation lists three monitoring endpoints: /healthz, /healthz/readiness, and /metrics. The shallow healthz route and readiness route answer different questions. n8n also documents configuration for the health endpoint path in queue-mode deployments.

curl http://127.0.0.1:5678/healthz
curl http://127.0.0.1:5678/healthz/readiness

Micronaut health endpoint

The current Micronaut guide explains how to expose a health endpoint through the Micronaut Management feature. Production teams should verify whether details are exposed publicly, whether a separate management port is used, and which indicators affect readiness.

curl http://127.0.0.1:8080/health

Skyvern API health endpoint /api/v1/health

The keyword skyvern api health endpoint /api/v1/health is useful as a search phrase, but the route must be verified rather than assumed. Current Skyvern repository testing guidance verifies backend API reachability through an API request. A current Skyvern issue references an internal auth-status path used by the UI, which demonstrates that deployment diagnostics can differ from a generic /api/v1/health expectation.

Kubernetes API health endpoints

The Kubernetes API server provides healthz, livez, and readyz, and recommends relying on HTTP status for machine checks. For ordinary workloads, Kubernetes supports HTTP, TCP, command, and gRPC probe mechanisms.

AI API Health Check and Readiness Probe Design

An AI API health check should distinguish whether the local API process is alive from whether the full AI workflow is ready. A service may be running while its model configuration, worker pool, queue, vector database, GPU capacity, inference server, or external provider is unavailable.

AI API readiness probe example

GET /ready

Ready when:
- API process is initialized
- worker pool has capacity
- required queue is reachable
- selected model route is configured
- required data store is available

Not required on every probe:
- a full paid model generation
- a large vector search
- document processing
- third-party browser automation

This pattern reduces false failures and prevents the readiness endpoint from becoming an expensive workload itself.

Operating System, Container, and Service Examples

Docker’s current Dockerfile reference documents the HEALTHCHECK instruction for determining whether a container is still working. Container state and application readiness are related but not identical, so the command should query the real application route.

Best Way to Monitor Endpoint Health

The best way to monitor endpoint health is not one periodic curl command. It is a layered health endpoint monitoring pattern that combines active checks, passive runtime observation, infrastructure telemetry, dependency metrics, and business outcomes.

Poor endpoint health visibility

Poor endpoint health visibility occurs when teams only know that a process returned 200, but cannot tell which routes are slow, which customers are failing, whether a gateway is blocking traffic, whether a dependency is saturated, or whether abusive traffic is consuming capacity.

How to assess endpoint health

• Availability: success rate and repeated failure.
• Latency: p50, p95, and p99 response time.
• Correctness: expected response shape and required fields.
• Readiness: instance acceptance of new traffic.
• Dependencies: database, cache, queue, identity, model, and partner services.
• Business result: completion of important customer journeys.
• Security: unusual identities, abuse, authorization failure, data leakage, and response anomalies.

OWASP logging guidance recommends telemetry that supports operations, security, investigation, and audit use cases. For broader architecture, see enterprise API monitoring best practices and centralized SIEM log forwarding formats.

Health Endpoint Security and Ammune Runtime Visibility

A health endpoint is part of the API attack surface. OWASP REST Security guidance recommends strong authentication and authorization, safe input handling, appropriate status codes, and controlled information exposure.

Health endpoint security controls

1. Return minimal public information such as OK, READY, or NOT READY.
2. Do not expose credentials, tokens, internal IPs, dependency URLs, software versions, stack traces, or customer data.
3. Protect detailed diagnostics with network restrictions and authentication.
4. Keep the endpoint cheap and rate controlled so it cannot amplify denial-of-service activity.
5. Log state changes, repeated failure, unusual sources, and latency increases without recording noisy successful probes forever.
6. Monitor the same API beyond the check endpoint to detect abuse and real customer impact.

Related Ammune guidance includes REST API endpoint security best practices, internal API security best practices, and the API runtime security protection platform.

How Ammune complements API health checks

Ammune should complement—not replace—liveness, readiness, metrics, tracing, logs, infrastructure monitoring, and synthetic checks. Validate deployment mode, traffic visibility, throughput, latency, encryption architecture, alert quality, and enforcement through a proof of value.

Production API Health Check Checklist

Conclusion

A useful REST API health check endpoint begins with a small, predictable request such as curl http://127.0.0.1:8080/health. From there, separate liveness from readiness, choose a documented route, return meaningful status codes, prevent stale caching, use bounded dependency checks, protect diagnostics, and require repeated failure before disruptive action.

The best way to monitor endpoint health combines active checks with passive API traffic visibility, real latency and error telemetry, dependency metrics, customer-journey validation, and security monitoring. Ammune can add runtime API discovery, behavior analytics, request and response context, abuse detection, and SIEM-ready evidence beyond the green-or-red health result.

Frequently Asked Questions About API Health Checks