diff --git a/.golangci.yml b/.golangci.yml
new file mode 100644
index 0000000..fe617bb
--- /dev/null
+++ b/.golangci.yml
@@ -0,0 +1,133 @@
+linters-settings:
+  # depguard: // Specific for golangci repository
+  #   list-type: blacklist
+  #   packages:
+  #     # logging is allowed only by logutils.Log, logrus
+  #     # is allowed to use only in logutils package
+  #     - github.com/sirupsen/logrus
+  #   packages-with-error-message:
+  #     - github.com/sirupsen/logrus: 'logging is allowed only by logutils.Log'
+  dupl:
+    threshold: 100
+  funlen:
+    lines: 100
+    statements: 50
+  gci:
+    sections:
+      prefix(fetchsysd)
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - dupImport # https://github.com/go-critic/go-critic/issues/845
+      - ifElseChain
+      - octalLiteral
+      # - whyNoLint
+      - wrapperFunc
+  gocyclo:
+    min-complexity: 15
+  goimports:
+    local-prefixes: localenv
+  mnd:
+    # don't include the "operation" and "assign"
+    checks:
+      - argument
+      - case
+      - condition
+      - return
+  govet:
+    shadow: true
+    # settings: // Specific for golangci repository
+    #   printf:
+    #     funcs:
+    #       - (github.com/golangci/golangci-lint/pkg/logutils.Log).Infof
+    #       - (github.com/golangci/golangci-lint/pkg/logutils.Log).Warnf
+    #       - (github.com/golangci/golangci-lint/pkg/logutils.Log).Errorf
+    #       - (github.com/golangci/golangci-lint/pkg/logutils.Log).Fatalf
+  lll:
+    line-length: 200
+  maligned:
+    suggest-new: true
+  misspell:
+    locale: US
+  nolintlint:
+    allow-leading-space: true # don't require machine-readable nolint directives (i.e. with no leading space)
+    allow-unused: false # report any unused nolint directives
+    require-explanation: false # don't require an explanation for nolint directives
+    require-specific: false # don't require nolint directives to be specific about which linter is being skipped
+  errcheck:
+    check-blank: true
+    exclude-functions:
+      - '(*github.com/gin-gonic/gin.Error).SetType'
+      - '(*github.com/gin-gonic/gin.Context).Error'
+
+linters:
+  disable-all: true
+  enable:
+    - bodyclose
+    # - deadcode # deprecated (since v1.49.0)
+    # - depguard
+    - dogsled
+    - dupl
+    - errcheck
+    - copyloopvar
+    - exhaustive
+    - funlen
+    - gochecknoinits
+    - goconst
+    - gocritic
+    - gocyclo
+    - gofmt
+    - goimports
+    - mnd
+    - goprintffuncname
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - lll
+    - misspell
+    - nakedret
+    - noctx
+    - nolintlint
+    # - rowserrcheck # https://github.com/golangci/golangci-lint/issues/2649
+    - staticcheck
+    # - structcheck # https://github.com/golangci/golangci-lint/issues/2649
+    - stylecheck
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    # - varcheck # deprecated (since v1.49.0)
+    - whitespace
+    # - gochecknoglobals # too many global in ds9
+
+  # don't enable:
+  # - asciicheck
+  # - scopelint
+  # - gocognit
+  # - godot
+  # - godox
+  # - goerr113
+  # - interfacer
+  # - maligned
+  # - nestif
+  # - prealloc
+  # - testpackage
+  # - revive
+  # - wsl
+
+# issues:
+# Excluding configuration per-path, per-linter, per-text and per-source
+# fix: true
+
+run:
+  timeout: 5m
+  skip-dirs: []
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..4f27c10
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# librapi
+
+A simple server to store, search and download books.
\ No newline at end of file
diff --git a/handlers/login/handler.go b/handlers/login/handler.go
index d6e56c7..ecbff85 100644
--- a/handlers/login/handler.go
+++ b/handlers/login/handler.go
@@ -113,7 +113,7 @@ func postLogin(w http.ResponseWriter, r *http.Request, s *services.SessionStore)
 			http.Error(w, "unexpected error occurred", http.StatusInternalServerError)
 		}
 
-		w.WriteHeader(400)
+		w.WriteHeader(http.StatusBadRequest)
 		fmt.Fprint(w, buf.String())
 		return
 	}
@@ -128,7 +128,7 @@ func postLogin(w http.ResponseWriter, r *http.Request, s *services.SessionStore)
 			return
 		}
 
-		w.WriteHeader(401)
+		w.WriteHeader(http.StatusUnauthorized)
 		fmt.Fprint(w, buf.String())
 		return
 	}
@@ -137,7 +137,9 @@ func postLogin(w http.ResponseWriter, r *http.Request, s *services.SessionStore)
 	if err != nil {
 		log.Err(err).Msg("unable to create a new session")
 		http.Error(w, "unexpected error occurred", http.StatusInternalServerError)
+		return
 	}
+
 	cookie := session.GenerateCookie()
 	http.SetCookie(w, cookie)
 
diff --git a/handlers/upload/handler.go b/handlers/upload/handler.go
index fb0c0ad..19899b2 100644
--- a/handlers/upload/handler.go
+++ b/handlers/upload/handler.go
@@ -128,8 +128,8 @@ func extractBookForm(r *http.Request) BookForm {
 	}
 	bf.Editor.Value = editor
 
-	if a := r.FormValue(bf.Authors.Name); len(a) != 0 {
-		bf.Authors.Value = strings.Split(",", a)
+	if a := r.FormValue(bf.Authors.Name); a != "" {
+		bf.Authors.Value = strings.Split(a, ",")
 	} else {
 		bf.Authors.Err = ErrInvalidAuthors.Error()
 	}
@@ -141,8 +141,8 @@ func extractBookForm(r *http.Request) BookForm {
 	}
 	bf.Year.Value = year
 
-	if kw := r.FormValue(bf.Keywords.Name); len(kw) != 0 {
-		bf.Keywords.Value = strings.Split(",", kw)
+	if kw := r.FormValue(bf.Keywords.Name); kw != "" {
+		bf.Keywords.Value = strings.Split(kw, ",")
 	}
 
 	file, fileh, err := r.FormFile(bf.File.Name)
@@ -179,7 +179,7 @@ func postUploadFile(w http.ResponseWriter, r *http.Request, s *services.SessionS
 			http.Error(w, "unexpected error occurred", http.StatusInternalServerError)
 		}
 
-		w.WriteHeader(401)
+		w.WriteHeader(http.StatusUnauthorized)
 		fmt.Fprint(w, buf.String())
 		return
 	}
@@ -192,7 +192,7 @@ func postUploadFile(w http.ResponseWriter, r *http.Request, s *services.SessionS
 	}
 
 	if bf.HasErrors() {
-		w.WriteHeader(400)
+		w.WriteHeader(http.StatusBadRequest)
 		fmt.Fprint(w, buf.String())
 		return
 	}
@@ -202,12 +202,12 @@ func postUploadFile(w http.ResponseWriter, r *http.Request, s *services.SessionS
 
 	dst, err := os.Create(filename)
 	if err != nil {
-		if err := uploadForm.Execute(buf, &BookForm{Error: "unexpected error occured while creating file"}); err != nil {
+		if err := uploadForm.Execute(buf, &BookForm{Error: "unexpected error occurred while creating file"}); err != nil {
 			log.Err(err).Msg("unable to generate template")
 			http.Error(w, "unexpected error occurred", http.StatusInternalServerError)
 		}
 
-		w.WriteHeader(500)
+		w.WriteHeader(http.StatusInternalServerError)
 		fmt.Fprint(w, buf.String())
 		return
 	}
@@ -215,13 +215,13 @@ func postUploadFile(w http.ResponseWriter, r *http.Request, s *services.SessionS
 	defer dst.Close()
 
 	if _, err := io.Copy(dst, bf.File.Value.file); err != nil {
-		if err := uploadForm.Execute(buf, &BookForm{Error: "unexpected error occured while uploading file"}); err != nil {
+		if err := uploadForm.Execute(buf, &BookForm{Error: "unexpected error occurred while uploading file"}); err != nil {
 			log.Err(err).Msg("unable to generate template")
 			http.Error(w, "unexpected error occurred", http.StatusInternalServerError)
 			return
 		}
 
-		w.WriteHeader(500)
+		w.WriteHeader(http.StatusInternalServerError)
 		fmt.Fprint(w, buf.String())
 		return
 	}
@@ -236,7 +236,7 @@ func postUploadFile(w http.ResponseWriter, r *http.Request, s *services.SessionS
 	fmt.Fprint(w, buf.String())
 }
 
-func getUploadFile(w http.ResponseWriter, r *http.Request) {
+func getUploadFile(w http.ResponseWriter, _ *http.Request) {
 	uploadForm := templates.GetUploadForm()
 	if uploadForm == nil {
 		log.Error().Msg("unable to load upload form")
diff --git a/services/sessions.go b/services/sessions.go
index e5f7cf6..1349a8a 100644
--- a/services/sessions.go
+++ b/services/sessions.go
@@ -30,12 +30,12 @@ var APISecure = sync.OnceValue[bool](func() bool {
 })
 
 var (
-	ErrSessionIdCollision = errors.New("sessionId collision")
+	ErrSessionIDCollision = errors.New("sessionId collision")
 	ErrUnauthorized       = errors.New("unauthorized")
 )
 
 func generateSessionID() (string, error) {
-	sessionID := make([]byte, 32)
+	sessionID := make([]byte, 32) //nolint
 	if _, err := rand.Read(sessionID); err != nil {
 		return "", err
 	}
@@ -45,7 +45,7 @@ func generateSessionID() (string, error) {
 
 type Session struct {
 	l              sync.RWMutex
-	sessionId      string
+	sessionID      string
 	expirationTime time.Time
 }
 
@@ -55,7 +55,7 @@ func (s *Session) GenerateCookie() *http.Cookie {
 
 	return &http.Cookie{
 		Name:     "session_id",
-		Value:    s.sessionId,
+		Value:    s.sessionID,
 		HttpOnly: true,
 		Secure:   APISecure(),
 		Expires:  s.expirationTime,
@@ -97,13 +97,13 @@ func (s *SessionStore) purge() {
 	}
 
 	for _, session := range toDelete {
-		log.Debug().Str("sessionId", session.sessionId).Msg("purge expired session")
-		delete(s.sessions, session.sessionId)
+		log.Debug().Str("sessionId", session.sessionID).Msg("purge expired session")
+		delete(s.sessions, session.sessionID)
 	}
 }
 
 func (s *SessionStore) purgeWorker() {
-	ticker := time.NewTicker(10 * time.Second)
+	ticker := time.NewTicker(10 * time.Second) //nolint
 	go func() {
 		for {
 			select {
@@ -127,7 +127,7 @@ func (s *SessionStore) Done() <-chan struct{} {
 }
 
 func (s *SessionStore) NewSession() (*Session, error) {
-	sessionId, err := generateSessionID()
+	sessionID, err := generateSessionID()
 	if err != nil {
 		log.Err(err).Msg("unable to generate sessionId")
 		return nil, err
@@ -136,14 +136,14 @@ func (s *SessionStore) NewSession() (*Session, error) {
 	s.l.Lock()
 	defer s.l.Unlock()
 
-	if _, ok := s.sessions[sessionId]; ok {
-		log.Error().Str("sessionId", sessionId).Msg("sessionId collision")
-		return nil, ErrSessionIdCollision
+	if _, ok := s.sessions[sessionID]; ok {
+		log.Error().Str("sessionId", sessionID).Msg("sessionId collision")
+		return nil, ErrSessionIDCollision
 	}
 
 	now := time.Now().Add(APISessionExpirationDuration())
-	session := Session{expirationTime: now, sessionId: sessionId}
-	s.sessions[sessionId] = &session
+	session := Session{expirationTime: now, sessionID: sessionID}
+	s.sessions[sessionID] = &session
 
 	return &session, nil
 }