diff --git a/context.go b/context.go
index e9c2fd6..0699ec5 100644
--- a/context.go
+++ b/context.go
@@ -70,9 +70,17 @@ func (c *Context) NoContent(code int) error {
 
 // JSON returns the given status code and writes JSON to the body
 func (c *Context) JSON(code int, data interface{}) error {
+	// write to buffer first in case of error
+	var buf bytes.Buffer
+	err := json.NewEncoder(&buf).Encode(data)
+	if err != nil {
+		return err
+	}
+
 	c.Response.Header().Set(`Content-Type`, `application/json`)
 	c.Response.WriteHeader(code)
-	return json.NewEncoder(c.Response).Encode(data) // TODO: Encode to buffer first to prevent partial responses on error
+	_, err = io.Copy(c.Response, &buf)
+	return err
 }
 
 // Render renders a templating using the Renderer set in router
diff --git a/default.go b/default.go
index ecda050..075cdf1 100644
--- a/default.go
+++ b/default.go
@@ -13,7 +13,7 @@ func defaultMethodNotAllowedHandler(c *Context) error {
 	return c.StatusText(http.StatusMethodNotAllowed)
 }
 
-func defaultErrorHandler(c *Context, err interface{}) {
+func defaultErrorHandler(c *Context, _ interface{}) {
 	_ = c.StatusText(http.StatusInternalServerError)
 }
 
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..7ae044b
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module git.fuyu.moe/Fuyu/router
+
+go 1.22.0
+
+require github.com/julienschmidt/httprouter v1.3.0
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..096c54e
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/julienschmidt/httprouter v1.3.0 h1:U0609e9tgbseu3rBINet9P48AI/D3oJs4dN7jwJOQ1U=
+github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=
diff --git a/group.go b/group.go
index e9a1451..150876d 100644
--- a/group.go
+++ b/group.go
@@ -1,6 +1,9 @@
 package router
 
-import urlpath "path"
+import (
+	urlpath "path"
+	"slices"
+)
 
 func join(prefix, path string) string {
 	return urlpath.Join(prefix, urlpath.Clean(path))
@@ -15,40 +18,40 @@ type Group struct {
 
 // Group creates a new router group with a shared prefix and set of middlewares
 func (g *Group) Group(prefix string, middleware ...Middleware) *Group {
-	return &Group{prefix: join(g.prefix, prefix), router: g.router, middleware: append(g.middleware, middleware...)}
+	return &Group{prefix: join(g.prefix, prefix), router: g.router, middleware: slices.Concat(g.middleware, middleware)}
 }
 
 // GET adds a GET route
 func (g *Group) GET(path string, handle Handle, middleware ...Middleware) {
-	g.router.GET(join(g.prefix, path), handle, append(g.middleware, middleware...)...)
+	g.router.GET(join(g.prefix, path), handle, slices.Concat(g.middleware, middleware)...)
 }
 
 // POST adds a POST route
 func (g *Group) POST(path string, handle interface{}, middleware ...Middleware) {
-	g.router.POST(join(g.prefix, path), handle, append(g.middleware, middleware...)...)
+	g.router.POST(join(g.prefix, path), handle, slices.Concat(g.middleware, middleware)...)
 }
 
 // DELETE adds a DELETE route
 func (g *Group) DELETE(path string, handle Handle, middleware ...Middleware) {
-	g.router.DELETE(join(g.prefix, path), handle, append(g.middleware, middleware...)...)
+	g.router.DELETE(join(g.prefix, path), handle, slices.Concat(g.middleware, middleware)...)
 }
 
 // PUT adds a PUT route
 func (g *Group) PUT(path string, handle interface{}, middleware ...Middleware) {
-	g.router.PUT(join(g.prefix, path), handle, append(g.middleware, middleware...)...)
+	g.router.PUT(join(g.prefix, path), handle, slices.Concat(g.middleware, middleware)...)
 }
 
 // PATCH adds a PATCH route
 func (g *Group) PATCH(path string, handle interface{}, middleware ...Middleware) {
-	g.router.PATCH(join(g.prefix, path), handle, append(g.middleware, middleware...)...)
+	g.router.PATCH(join(g.prefix, path), handle, slices.Concat(g.middleware, middleware)...)
 }
 
 // HEAD adds a HEAD route
 func (g *Group) HEAD(path string, handle Handle, middleware ...Middleware) {
-	g.router.HEAD(join(g.prefix, path), handle, append(g.middleware, middleware...)...)
+	g.router.HEAD(join(g.prefix, path), handle, slices.Concat(g.middleware, middleware)...)
 }
 
 // OPTIONS adds a OPTIONS route
 func (g *Group) OPTIONS(path string, handle Handle, middleware ...Middleware) {
-	g.router.OPTIONS(join(g.prefix, path), handle, append(g.middleware, middleware...)...)
+	g.router.OPTIONS(join(g.prefix, path), handle, slices.Concat(g.middleware, middleware)...)
 }
diff --git a/router.go b/router.go
index d869fc6..f3252d9 100644
--- a/router.go
+++ b/router.go
@@ -3,8 +3,10 @@ package router
 import (
 	"context"
 	"crypto/tls"
+	"errors"
 	"net/http"
 	"reflect"
+	"slices"
 	"time"
 
 	"github.com/julienschmidt/httprouter"
@@ -44,7 +46,12 @@ type Router struct {
 
 // New returns a new Router
 func New() *Router {
-	return &Router{Reader: defaultReader, NotFoundHandler: defaultNotFoundHandler, MethodNotAllowedHandler: defaultMethodNotAllowedHandler, ErrorHandler: defaultErrorHandler}
+	return &Router{
+		Reader:                  defaultReader,
+		NotFoundHandler:         defaultNotFoundHandler,
+		MethodNotAllowedHandler: defaultMethodNotAllowedHandler,
+		ErrorHandler:            defaultErrorHandler,
+	}
 }
 
 // Use adds a global middleware
@@ -120,7 +127,7 @@ func (r *Router) Stop() error {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	defer cancel()
 	err := r.server.Shutdown(ctx)
-	if err == context.DeadlineExceeded {
+	if errors.Is(err, context.DeadlineExceeded) {
 		err = r.server.Close()
 	}
 	r.server = nil
@@ -137,11 +144,9 @@ func (r *Router) getHttpr() http.Handler {
 			handle = handlePOST(r, v.Handle)
 		}
 
-		middleware := make([]Middleware, len(r.middleware)+len(v.Middleware))
-		copy(middleware, r.middleware)
-		copy(middleware[len(r.middleware):], v.Middleware)
-
-		httpr.Handle(v.Method, v.Path, handleReq(r, handle, middleware))
+		httpr.Handle(v.Method, v.Path, handleReq(r, handle,
+			slices.Concat(r.middleware, v.Middleware),
+		))
 	}
 
 	httpr.NotFound = http.HandlerFunc(func(res http.ResponseWriter, req *http.Request) {
@@ -232,7 +237,6 @@ func handleReq(r *Router, handle Handle, m []Middleware) httprouter.Handle {
 		}
 
 		err := f(c)
-
 		if err != nil {
 			r.ErrorHandler(c, err)
 		}