diff --git a/internal/handlers/auth.go b/internal/handlers/auth.go
new file mode 100644
index 0000000..bc44866
--- /dev/null
+++ b/internal/handlers/auth.go
@@ -0,0 +1,186 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+)
+
+const minPasswordLength = 8
+
+// HandleRegister creates a new user with a password.
+func (hdlr *Handlers) HandleRegister() http.HandlerFunc {
+	return func(
+		writer http.ResponseWriter,
+		request *http.Request,
+	) {
+		request.Body = http.MaxBytesReader(
+			writer, request.Body, hdlr.maxBodySize(),
+		)
+
+		hdlr.handleRegister(writer, request)
+	}
+}
+
+func (hdlr *Handlers) handleRegister(
+	writer http.ResponseWriter,
+	request *http.Request,
+) {
+	type registerRequest struct {
+		Nick     string `json:"nick"`
+		Password string `json:"password"`
+	}
+
+	var payload registerRequest
+
+	err := json.NewDecoder(request.Body).Decode(&payload)
+	if err != nil {
+		hdlr.respondError(
+			writer, request,
+			"invalid request body",
+			http.StatusBadRequest,
+		)
+
+		return
+	}
+
+	payload.Nick = strings.TrimSpace(payload.Nick)
+
+	if !validNickRe.MatchString(payload.Nick) {
+		hdlr.respondError(
+			writer, request,
+			"invalid nick format",
+			http.StatusBadRequest,
+		)
+
+		return
+	}
+
+	if len(payload.Password) < minPasswordLength {
+		hdlr.respondError(
+			writer, request,
+			"password must be at least 8 characters",
+			http.StatusBadRequest,
+		)
+
+		return
+	}
+
+	sessionID, clientID, token, err :=
+		hdlr.params.Database.RegisterUser(
+			request.Context(),
+			payload.Nick,
+			payload.Password,
+		)
+	if err != nil {
+		hdlr.handleRegisterError(
+			writer, request, err,
+		)
+
+		return
+	}
+
+	hdlr.deliverMOTD(request, clientID, sessionID)
+
+	hdlr.respondJSON(writer, request, map[string]any{
+		"id":    sessionID,
+		"nick":  payload.Nick,
+		"token": token,
+	}, http.StatusCreated)
+}
+
+func (hdlr *Handlers) handleRegisterError(
+	writer http.ResponseWriter,
+	request *http.Request,
+	err error,
+) {
+	if strings.Contains(err.Error(), "UNIQUE") {
+		hdlr.respondError(
+			writer, request,
+			"nick already taken",
+			http.StatusConflict,
+		)
+
+		return
+	}
+
+	hdlr.log.Error(
+		"register user failed", "error", err,
+	)
+	hdlr.respondError(
+		writer, request,
+		"internal error",
+		http.StatusInternalServerError,
+	)
+}
+
+// HandleLogin authenticates a user with nick and password.
+func (hdlr *Handlers) HandleLogin() http.HandlerFunc {
+	return func(
+		writer http.ResponseWriter,
+		request *http.Request,
+	) {
+		request.Body = http.MaxBytesReader(
+			writer, request.Body, hdlr.maxBodySize(),
+		)
+
+		hdlr.handleLogin(writer, request)
+	}
+}
+
+func (hdlr *Handlers) handleLogin(
+	writer http.ResponseWriter,
+	request *http.Request,
+) {
+	type loginRequest struct {
+		Nick     string `json:"nick"`
+		Password string `json:"password"`
+	}
+
+	var payload loginRequest
+
+	err := json.NewDecoder(request.Body).Decode(&payload)
+	if err != nil {
+		hdlr.respondError(
+			writer, request,
+			"invalid request body",
+			http.StatusBadRequest,
+		)
+
+		return
+	}
+
+	payload.Nick = strings.TrimSpace(payload.Nick)
+
+	if payload.Nick == "" || payload.Password == "" {
+		hdlr.respondError(
+			writer, request,
+			"nick and password required",
+			http.StatusBadRequest,
+		)
+
+		return
+	}
+
+	sessionID, _, token, err :=
+		hdlr.params.Database.LoginUser(
+			request.Context(),
+			payload.Nick,
+			payload.Password,
+		)
+	if err != nil {
+		hdlr.respondError(
+			writer, request,
+			"invalid credentials",
+			http.StatusUnauthorized,
+		)
+
+		return
+	}
+
+	hdlr.respondJSON(writer, request, map[string]any{
+		"id":    sessionID,
+		"nick":  payload.Nick,
+		"token": token,
+	}, http.StatusOK)
+}