fiber/docs/middleware/healthcheck.md
Juan Calderon-Perez 67a2166788
📒 docs: Fix Healthcheck middleware documentation (#3657)
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
2025-08-04 09:13:54 +02:00

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---
id: healthcheck
---
# Health Check
Middleware to implement liveness, readiness, and startup probes for [Fiber](https://github.com/gofiber/fiber) applications. It exposes a generic probe handler; you decide which endpoints to register. Convenience constants are available for the conventional endpoints (`/livez`, `/readyz`, and `/startupz`).
## Overview
Register the middleware on any endpoint you want to expose a probe on. The package exports constants for the conventional liveness, readiness, and startup endpoints:
```go
app.Get(healthcheck.LivenessEndpoint, healthcheck.New())
app.Get(healthcheck.ReadinessEndpoint, healthcheck.New())
app.Get(healthcheck.StartupEndpoint, healthcheck.New())
```
By default, the probe returns `true`, so each registered endpoint responds with `200 OK`. When the probe returns `false`, the middleware responds with `503 Service Unavailable`.
- **Liveness**: Checks if the server is running.
- **Readiness**: Checks if the application is ready to handle requests.
- **Startup**: Checks if the application has completed its startup sequence.
## Signatures
```go
func New(config ...Config) fiber.Handler
```
## Examples
Import the middleware package that is part of the [Fiber](https://github.com/gofiber/fiber) web framework
```go
import(
"github.com/gofiber/fiber/v3"
"github.com/gofiber/fiber/v3/middleware/healthcheck"
)
```
After you initiate your [Fiber](https://github.com/gofiber/fiber) app, register the middleware on the endpoints you need:
```go
// Use the default probe on the conventional endpoints
app.Get(healthcheck.LivenessEndpoint, healthcheck.New())
app.Get(healthcheck.ReadinessEndpoint, healthcheck.New(healthcheck.Config{
Probe: func(c fiber.Ctx) bool {
return serviceA.Ready() && serviceB.Ready()
},
}))
app.Get(healthcheck.StartupEndpoint, healthcheck.New())
// Register a custom endpoint
app.Get("/healthz", healthcheck.New())
```
The middleware only responds to GET requests. To register a probe on all methods, use `app.All`. Non-GET methods fall through to the next handler:
```go
app.All("/healthz", healthcheck.New())
```
## Config
```go
type Config struct {
// Next defines a function to skip this middleware when returned true. If this function returns true
// and no other handlers are defined for the route, Fiber will return a status 404 Not Found, since
// no other handlers were defined to return a different status.
//
// Optional. Default: nil
Next func(fiber.Ctx) bool
// Probe is executed to determine the current health state. It can be used for
// liveness, readiness or startup checks. Returning true indicates the application
// is healthy.
//
// Optional. Default: func(c fiber.Ctx) bool { return true }
Probe func(fiber.Ctx) bool
}
```
## Default Config
The default configuration used by this middleware is defined as follows:
```go
func defaultProbe(_ fiber.Ctx) bool { return true }
var ConfigDefault = Config{
Next: nil,
Probe: defaultProbe,
}
```