diff --git a/pkg/client/client.go b/pkg/client/client.go
index 8e4452d..b55b2bc 100644
--- a/pkg/client/client.go
+++ b/pkg/client/client.go
@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"encoding/binary"
-	"encoding/json"
 	"fmt"
-	"log"
 	"net/http"
 	"time"
 
@@ -18,7 +15,6 @@ type Client struct {
 	httpClient *http.Client
 	prefix     uint16
 	gen        *generation.Generator
-	domain     string // e.g. https://sho.rt
 
 	db         *bolt.DB
 	retryQueue chan shortenJob
@@ -26,13 +22,13 @@ type Client struct {
 }
 
 // NewClient with persistence and retry queue
-func NewClient(serverURL, domain string) (*Client, error) {
+func NewClient(serverURL string, folder string) (*Client, error) {
 	httpClient, baseURL, err := createHTTPClient(serverURL)
 	if err != nil {
 		return nil, err
 	}
 
-	db, err := bolt.Open(dbFileName, 0600, &bolt.Options{Timeout: 1 * time.Second})
+	db, err := bolt.Open(folder+"/"+dbFileName, 0600, &bolt.Options{Timeout: 1 * time.Second})
 	if err != nil {
 		return nil, err
 	}
@@ -40,7 +36,6 @@ func NewClient(serverURL, domain string) (*Client, error) {
 	cli := &Client{
 		serverURL:  baseURL,
 		httpClient: httpClient,
-		domain:     domain,
 		db:         db,
 		retryQueue: make(chan shortenJob, 1000),
 		stopRetry:  make(chan struct{}),
@@ -109,27 +104,10 @@ func NewClient(serverURL, domain string) (*Client, error) {
 func (c *Client) Shorten(longURL string) string {
 	shortID := c.gen.NextID()
 
-	go func() {
-		payload := map[string]string{
-			"id":  shortID,
-			"url": longURL,
-		}
-		data, _ := json.Marshal(payload)
+	go c.enqueueJob(shortenJob{
+		ID:  shortID,
+		URL: longURL,
+	})
 
-		req, err := http.NewRequest("POST", fmt.Sprintf("%s/shorten", c.serverURL), bytes.NewReader(data))
-		if err != nil {
-			log.Println("shorten request build error:", err)
-			return
-		}
-		req.Header.Set("Content-Type", "application/json")
-
-		resp, err := c.httpClient.Do(req)
-		if err != nil {
-			log.Println("shorten request failed:", err)
-			return
-		}
-		defer resp.Body.Close()
-	}()
-
-	return fmt.Sprintf("%s/%s", c.domain, shortID)
+	return shortID
 }
diff --git a/pkg/client/store.go b/pkg/client/store.go
index 41f396d..df1d700 100644
--- a/pkg/client/store.go
+++ b/pkg/client/store.go
@@ -1,11 +1,13 @@
 package client
 
 import (
-	"bytes"
+	"encoding/binary"
 	"encoding/json"
 	"fmt"
+	"io"
 	"log"
 	"net/http"
+	"strings"
 	"time"
 
 	bolt "go.etcd.io/bbolt"
@@ -23,19 +25,18 @@ type shortenJob struct {
 }
 
 func (c *Client) registerPrefix() (uint16, error) {
-	resp, err := c.httpClient.Post(fmt.Sprintf("%s/register", c.serverURL), "application/json", nil)
+	resp, err := c.httpClient.Get(fmt.Sprintf("%s/register", c.serverURL))
 	if err != nil {
 		return 0, err
 	}
 	defer resp.Body.Close()
 
-	var result struct {
-		Prefix uint16 `json:"prefix"`
-	}
-	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+	bytes, err := io.ReadAll(resp.Body)
+	if err != nil {
 		return 0, err
 	}
-	return result.Prefix, nil
+
+	return binary.LittleEndian.Uint16(bytes), nil
 }
 
 func (c *Client) loadRetryJobs() {
@@ -108,18 +109,10 @@ func (c *Client) deleteJobFromDB(job shortenJob) {
 }
 
 func (c *Client) sendShortenJob(job shortenJob) error {
-	payload := map[string]string{
-		"id":  job.ID,
-		"url": job.URL,
-	}
-	data, _ := json.Marshal(payload)
-
-	req, err := http.NewRequest("POST", fmt.Sprintf("%s/shorten", c.serverURL), bytes.NewReader(data))
+	req, err := http.NewRequest("POST", fmt.Sprintf("%s/shorten?s=%s", c.serverURL, job.ID), strings.NewReader(job.URL))
 	if err != nil {
 		return err
 	}
-	req.Header.Set("Content-Type", "application/json")
-
 	resp, err := c.httpClient.Do(req)
 	if err != nil {
 		return err