diff --git a/internal/relay/relay.go b/internal/relay/relay.go
new file mode 100644
index 0000000..2ff1588
--- /dev/null
+++ b/internal/relay/relay.go
@@ -0,0 +1,149 @@
+package relay
+
+import (
+ "fmt"
+ "net/http"
+ "sync"
+)
+
+const Port = 19765
+
+type Server struct {
+ mu sync.Mutex
+ clients map[chan string]struct{}
+ currentURL string
+ server *http.Server
+}
+
+func New() *Server {
+ return &Server{clients: make(map[chan string]struct{})}
+}
+
+func (s *Server) Start() {
+ mux := http.NewServeMux()
+ mux.HandleFunc("/sse", s.handleSSE)
+ mux.HandleFunc("/jira", s.handleJira)
+ mux.HandleFunc("/", s.handleIndex)
+ s.server = &http.Server{
+ Addr: fmt.Sprintf("127.0.0.1:%d", Port),
+ Handler: mux,
+ }
+ go func() { _ = s.server.ListenAndServe() }()
+}
+
+func (s *Server) Stop() {
+ if s.server != nil {
+ _ = s.server.Close()
+ }
+}
+
+// Broadcast sends a new Jira URL to all connected relay pages.
+func (s *Server) Broadcast(url string) {
+ s.mu.Lock()
+ s.currentURL = url
+ clients := make([]chan string, 0, len(s.clients))
+ for ch := range s.clients {
+ clients = append(clients, ch)
+ }
+ s.mu.Unlock()
+ for _, ch := range clients {
+ select {
+ case ch <- url:
+ default:
+ }
+ }
+}
+
+func (s *Server) handleSSE(w http.ResponseWriter, r *http.Request) {
+ flusher, ok := w.(http.Flusher)
+ if !ok {
+ http.Error(w, "streaming unsupported", http.StatusInternalServerError)
+ return
+ }
+ w.Header().Set("Content-Type", "text/event-stream")
+ w.Header().Set("Cache-Control", "no-cache")
+ w.Header().Set("Connection", "keep-alive")
+ w.Header().Set("Access-Control-Allow-Origin", "*")
+
+ ch := make(chan string, 2)
+ s.mu.Lock()
+ s.clients[ch] = struct{}{}
+ current := s.currentURL
+ s.mu.Unlock()
+
+ defer func() {
+ s.mu.Lock()
+ delete(s.clients, ch)
+ s.mu.Unlock()
+ }()
+
+ // Send current URL immediately so relay opens Jira right on connect.
+ if current != "" {
+ _, _ = fmt.Fprintf(w, "data: %s\n\n", current)
+ flusher.Flush()
+ }
+
+ for {
+ select {
+ case url := <-ch:
+ _, _ = fmt.Fprintf(w, "data: %s\n\n", url)
+ flusher.Flush()
+ case <-r.Context().Done():
+ return
+ }
+ }
+}
+
+func (s *Server) handleIndex(w http.ResponseWriter, r *http.Request) {
+ w.Header().Set("Content-Type", "text/html; charset=utf-8")
+ w.Header().Set("Cache-Control", "no-cache")
+ _, _ = fmt.Fprint(w, relayHTML)
+}
+
+// handleJira redirects to the Jira URL passed in the ?url= query param.
+// This intermediate hop keeps the navigation same-origin so the relay page
+// can reliably set w.location.href without cross-origin restrictions.
+func (s *Server) handleJira(w http.ResponseWriter, r *http.Request) {
+ target := r.URL.Query().Get("url")
+ if target == "" {
+ http.Error(w, "missing url param", http.StatusBadRequest)
+ return
+ }
+ w.Header().Set("Cache-Control", "no-cache")
+ http.Redirect(w, r, target, http.StatusFound)
+}
+
+const relayHTML = "" +
+ "Daily Timer \xe2\x80\x94 relay" +
+ "" +
+ "Daily Timer \xe2\x80\x94 Jira relay
" +
+ "\xd0\xbd\xd0\xb5 \xd0\xb7\xd0xb0\xd0\xba\xd1\x80\xd1\x8b\xd0\xb2\xd0\xb0\xd0\xb9\xd1\x82\xd0\xb5 \xd1\x8d\xd1\x82\xd1\x83 \xd0\xb2\xd0\xba\xd0\xbb\xd0\xb0\xd0\xb4\xd0\xba\xd1\x83
" +
+ "" +
+ "" +
+ "" +
+ ""