diff --git a/Makefile b/Makefile
index 6aee967..1c7839d 100644
--- a/Makefile
+++ b/Makefile
@@ -10,11 +10,11 @@ docker:
 run:
 	docker ps -a | grep $(NAME) && ([ $$? -eq 0 ] && (docker stop $(NAME) && docker rm -f $(NAME))) || echo "no running container."
 	docker run -itd -v $(shell pwd)/data:/app/public/buildbox -p 6789:6789 --name $(NAME) ssaplayground:latest
-tidy-docker:
+tidy:
 	docker ps -a | grep $(NAME)
 	[ $$? -eq 0 ] && docker stop $(NAME) && docker rm -f $(NAME)
 	docker images -f "dangling=true" -q | xargs docker rmi -f
 	docker image prune -f
 clean:
 	rm -rf $(BUILD)
-.PHONY: all start docker update clean
\ No newline at end of file
+.PHONY: all docker run tidy clean
\ No newline at end of file
diff --git a/TODO.md b/TODO.md
index 371afea..8351162 100644
--- a/TODO.md
+++ b/TODO.md
@@ -9,4 +9,5 @@
 - [x] ~~Use short link instead of UUID?~~ seems no need
 - [x] share with /gossa?id=uuid -> access /gossa/uuid/main.go or /gossa/uuid/main_test.go, access /gossa/uuid/ssa.html
 - [x] ~~Better Editor: Monaco Editor~~ maybe not?
-- [ ] Containerized deployment
\ No newline at end of file
+- [x] Containerized deployment
+- [x] Support Go Modules
\ No newline at end of file
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 3ae8c91..bc8a607 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -1,7 +1,9 @@
 FROM golang:1.14-alpine
 WORKDIR /app
 ADD . /app
+# required for runtime/cgo
+RUN apk add g++
 RUN go get -u golang.org/x/tools/cmd/goimports && go mod tidy
-RUN go build -o ssaplayground.service -mod vendor
+RUN go build -o ssaplayground.service -mod=vendor
 EXPOSE 6789
 ENTRYPOINT [ "/app/ssaplayground.service", "-conf=/app/configs/docker.yaml"]
diff --git a/src/route/api.go b/src/route/api.go
index f06038e..62d46bd 100644
--- a/src/route/api.go
+++ b/src/route/api.go
@@ -46,6 +46,8 @@ type BuildSSAOutput struct {
 	Msg     string `json:"msg"`
 }
 
+// BuildSSA serves the code send by user and builds its SSA IR into html.
+// TODO: speedup for request response, e.g. as async rest api.
 func BuildSSA(c *gin.Context) {
 	// 1. create a folder in config.Get().Static/buildbox
 	out := BuildSSAOutput{
@@ -65,7 +67,7 @@ func BuildSSA(c *gin.Context) {
 	err = c.BindJSON(&in)
 	if err != nil {
 		os.Remove(path)
-		out.Msg = fmt.Sprintf("cannot bind input params, err: %v", err)
+		out.Msg = fmt.Sprintf("cannot bind input params, err: \n%v", err)
 		c.JSON(http.StatusInternalServerError, out)
 		return
 	}
@@ -86,24 +88,35 @@ func BuildSSA(c *gin.Context) {
 	err = ioutil.WriteFile(buildFile, []byte(in.Code), os.ModePerm)
 	if err != nil {
 		os.Remove(path)
-		out.Msg = err.Error()
+		out.Msg = fmt.Sprintf("cannot save your code, err: \n%v", err)
 		c.JSON(http.StatusInternalServerError, out)
 		return
 	}
 
-	// 3. goimports && GOSSAFUNC=foo go build
+	// 3.1 goimports
 	err = autoimports(buildFile)
 	if err != nil {
 		os.Remove(path)
-		out.Msg = err.Error()
+		out.Msg = fmt.Sprintf("cannot run autoimports for your code, err: \n%v", err)
 		c.JSON(http.StatusBadRequest, out)
 		return
 	}
+
+	// 3.2 go mod init gossa && go mod tidy
+	err = initModules(path)
+	if err != nil {
+		os.Remove(path)
+		out.Msg = fmt.Sprintf("cannot use go modules for your code, err: \n%v", err)
+		c.JSON(http.StatusBadRequest, out)
+		return
+	}
+
+	// 3.3 GOSSAFUNC=foo go build
 	outFile := filepath.Join(path, "/main.out")
 	err = buildSSA(in.FuncName, in.GcFlags, outFile, buildFile, isTest)
 	if err != nil {
 		os.Remove(path)
-		out.Msg = err.Error()
+		out.Msg = fmt.Sprintf("cannot build ssa for your code, err: \n%v", err)
 		c.JSON(http.StatusBadRequest, out)
 		return
 	}
@@ -138,6 +151,32 @@ func autoimports(outf string) error {
 	return nil
 }
 
+func initModules(path string) error {
+	// 1. go mod init
+	cmd := exec.Command("go", "mod", "init", "gossa")
+	cmd.Dir = path
+	cmd.Stderr = &bytes.Buffer{}
+	err := cmd.Run()
+	if err != nil {
+		msg := cmd.Stderr.(*bytes.Buffer).String()
+		msg = strings.ReplaceAll(msg, path, "$GOSSAPATH")
+		return errors.New(msg)
+	}
+
+	// 2. go mod tidy
+	cmd = exec.Command("go", "mod", "tidy")
+	cmd.Dir = path
+	cmd.Stderr = &bytes.Buffer{}
+	err = cmd.Run()
+	if err != nil {
+		msg := cmd.Stderr.(*bytes.Buffer).String()
+		msg = strings.ReplaceAll(msg, path, "$GOSSAPATH")
+		return errors.New(msg)
+	}
+
+	return nil
+}
+
 func buildSSA(funcname, gcflags, outf, buildf string, isTest bool) error {
 	var cmd *exec.Cmd
 	if !isTest {