Feature Request: Optional trailing slash handling (without redirect) #4411

Feature Description

Summary

Add an optional router configuration that allows Gin to treat routes with and without a trailing slash as equivalent, without performing a redirect.

When this option is enabled, routes like /health and /health/ should both be handled by the same route handler, even if only one of them was explicitly registered.

Motivation

Currently, Gin uses redirection to normalize trailing slashes.
If a route /health is registered, a request to /health/ results in a 301 or 307 redirect (depending on the request method).
While this behavior is correct for many web applications, it can be undesirable in APIs and microservices, where:

• Redirects introduce unnecessary latency.
• Some clients don’t expect or handle redirects well.
• Users want a consistent experience where /foo and /foo/ are logically the same endpoint.

This feature would make Gin more flexible and better suited for these use cases.

Proposal

Introduce a new Engine (or RouterGroup) option to enable this behavior, for example:

r := gin.New()
r.SetTrailingSlashBehavior(gin.TrailingSlashIgnore)

or via a configuration flag:

r := gin.Default()
r.IgnoreTrailingSlash = true

When enabled:

• /health and /health/ both match the same route, without redirecting.
• Registered paths in the router tree should match regardless of the trailing slash.
• The original Request.URL.Path should remain unchanged.

Example

r := gin.Default()
r.IgnoreTrailingSlash = true

r.GET("/health", func(c *gin.Context) {
    c.String(200, "ok")
})

r.Run()

Expected behavior:

Alternatives Considered

• RedirectTrailingSlash(false) disables redirects but results in 404 for the alternate path.
• Manually registering both /path and /path/.
• Middleware to normalize paths.

Implementation Notes

This feature would require a small change in the router tree’s lookup logic (tree.go, node.go), particularly in:

• findRoute
• getValue
• findCaseInsensitivePath

The idea is to optionally ignore the trailing slash difference when matching static nodes, for example:

if len(path) == len(prefix)-1 && prefix[len(prefix)-1] == '/' {
    if e.ignoreTrailingSlash {
        return matchedHandler
    }
}

References

• Related Gin issues: #388, #2415
• Similar feature in Echo: Echo#TrailingSlashRedirect

Benefit

This feature provides flexibility, avoids unwanted redirects, and improves developer experience for APIs that treat /path and /path/ equally.