diff --git a/client.go b/client.go
index b9857d7..21eb1e2 100644
--- a/client.go
+++ b/client.go
@@ -2,6 +2,7 @@ package fetch
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -30,6 +31,10 @@ func New(opts ...ClientOpts) Client {
 // WithProtocol returns function for setting http.Client.
 func WithHTTPClient(cli *http.Client) ClientOpts {
 	return func(c *client) {
+		if cli == nil {
+			c.client = &http.Client{}
+			return
+		}
 		c.client = cli
 	}
 }
@@ -44,11 +49,14 @@ func (c *client) Get(u *url.URL, opts ...RequestOpts) (Response, error) {
 func (c *client) GetWithContext(ctx context.Context, u *url.URL, opts ...RequestOpts) (Response, error) {
 	req, err := request(ctx, http.MethodGet, u, nil, opts...)
 	if err != nil {
-		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", u.String()))
+		if errors.Is(err, ErrInvalidURL) {
+			return nil, errs.Wrap(ErrInvalidURL, errs.WithCause(err), errs.WithContext("url", urlText(u)))
+		}
+		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", urlText(u)))
 	}
 	resp, err := c.fetch(req)
 	if err != nil {
-		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", u.String()))
+		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", urlText(u)))
 	}
 	return resp, nil
 }
@@ -63,11 +71,14 @@ func (c *client) Post(u *url.URL, payload io.Reader, opts ...RequestOpts) (Respo
 func (c *client) PostWithContext(ctx context.Context, u *url.URL, payload io.Reader, opts ...RequestOpts) (Response, error) {
 	req, err := request(ctx, http.MethodPost, u, payload, opts...)
 	if err != nil {
-		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", u.String()))
+		if errors.Is(err, ErrInvalidURL) {
+			return nil, errs.Wrap(ErrInvalidURL, errs.WithCause(err), errs.WithContext("url", urlText(u)))
+		}
+		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", urlText(u)))
 	}
 	resp, err := c.fetch(req)
 	if err != nil {
-		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", u.String()))
+		return nil, errs.Wrap(ErrInvalidRequest, errs.WithCause(err), errs.WithContext("url", urlText(u)))
 	}
 	return resp, nil
 }
@@ -100,6 +111,9 @@ func WithRequestHeaderSet(name, value string) RequestOpts {
 }
 
 func request(ctx context.Context, method string, u *url.URL, payload io.Reader, opts ...RequestOpts) (*http.Request, error) {
+	if u == nil {
+		return nil, errs.Wrap(ErrInvalidURL)
+	}
 	req, err := http.NewRequestWithContext(ctx, method, u.String(), payload)
 	if err != nil {
 		return nil, errs.Wrap(err)
@@ -114,6 +128,9 @@ func (c *client) fetch(request *http.Request) (Response, error) {
 	if c == nil {
 		c = New().(*client)
 	}
+	if c.client == nil {
+		c.client = &http.Client{}
+	}
 	r, err := c.client.Do(request)
 	if err != nil {
 		return nil, errs.Wrap(err)
@@ -121,7 +138,7 @@ func (c *client) fetch(request *http.Request) (Response, error) {
 	resp := &response{r}
 	if resp.StatusCode == 0 || resp.StatusCode >= http.StatusBadRequest {
 		err := ErrHTTPStatus
-		if cerr := resp.Close(); cerr != nil && !errs.Is(err, os.ErrClosed) {
+		if cerr := resp.Close(); cerr != nil && !errs.Is(cerr, os.ErrClosed) {
 			err = errs.Join(cerr, err)
 		}
 		return nil, errs.Wrap(fmt.Errorf("%w: status %d", err, resp.StatusCode), errs.WithContext("status", resp.StatusCode))
@@ -129,6 +146,13 @@ func (c *client) fetch(request *http.Request) (Response, error) {
 	return resp, nil
 }
 
+func urlText(u *url.URL) string {
+	if u == nil {
+		return ""
+	}
+	return u.String()
+}
+
 /* Copyright 2021-2025 Spiegel
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/dependency.png b/dependency.png
index a7f564c..2f44745 100644
Binary files a/dependency.png and b/dependency.png differ
diff --git a/fetch_test.go b/fetch_test.go
index 2198128..6bacdb9 100644
--- a/fetch_test.go
+++ b/fetch_test.go
@@ -4,7 +4,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"net/http"
+	"net/http/httptest"
 	"testing"
 
 	"github.com/goark/fetch"
@@ -44,6 +46,43 @@ func TestGet(t *testing.T) {
 	}
 }
 
+func TestGetWithNilURL(t *testing.T) {
+	resp, err := fetch.New().GetWithContext(context.Background(), nil)
+	if err == nil {
+		t.Fatal("error is nil, want ErrInvalidURL")
+	}
+	if !errors.Is(err, fetch.ErrInvalidURL) {
+		t.Fatalf("GetWithContext(nil) is %v, want ErrInvalidURL", err)
+	}
+	if resp != nil {
+		t.Fatal("response is not nil, want nil")
+	}
+}
+
+func TestWithHTTPClientNilFallback(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = io.WriteString(w, "ok")
+	}))
+	defer ts.Close()
+
+	u, err := fetch.URL(ts.URL)
+	if err != nil {
+		t.Fatalf("fetch.URL() error = %v", err)
+	}
+
+	resp, err := fetch.New(fetch.WithHTTPClient(nil)).GetWithContext(context.Background(), u)
+	if err != nil {
+		t.Fatalf("GetWithContext() error = %v", err)
+	}
+	if resp == nil {
+		t.Fatal("response is nil")
+	}
+	if cerr := resp.Close(); cerr != nil {
+		t.Fatalf("resp.Close() error = %v", cerr)
+	}
+}
+
 /* Copyright 2023-2025 Spiegel
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/go.sum b/go.sum
index 4e63d82..19eb1da 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,2 @@
-github.com/goark/errs v1.3.3 h1:vqzm/1aqvh4Ha8JDqIqIU5ZoBtjaRezFcMC55B5ljAM=
-github.com/goark/errs v1.3.3/go.mod h1:4xM7rorwYQlqh9kUhfKpC5P7VAJW2KfvuQpYnTaU0ek=
 github.com/goark/errs v1.3.4 h1:/+/xwF3UwXGxGGLurzBTaMMoryTBeaPfheJ1aW9cglA=
 github.com/goark/errs v1.3.4/go.mod h1:4xM7rorwYQlqh9kUhfKpC5P7VAJW2KfvuQpYnTaU0ek=
diff --git a/response.go b/response.go
index d3a52a2..03a6ddf 100644
--- a/response.go
+++ b/response.go
@@ -64,7 +64,7 @@ func (resp *response) DumpBodyAndClose() (b []byte, err error) {
 		if resp == nil {
 			return
 		}
-		if cerr := resp.Body().Close(); cerr != nil && !errs.Is(err, os.ErrClosed) {
+		if cerr := resp.Body().Close(); cerr != nil && !errs.Is(cerr, os.ErrClosed) {
 			err = errs.Join(cerr, err)
 		}
 	}()