diff --git a/d2cli/main.go b/d2cli/main.go
index 635a5e440..546a5a977 100644
--- a/d2cli/main.go
+++ b/d2cli/main.go
@@ -331,7 +331,7 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 	ctx, cancel := timelib.WithTimeout(ctx, time.Minute*2)
 	defer cancel()
 
-	_, written, err := compile(ctx, ms, plugins, layoutFlag, renderOpts, fontFamily, *animateIntervalFlag, inputPath, outputPath, *bundleFlag, *forceAppendixFlag, pw.Page)
+	_, written, err := compile(ctx, ms, plugins, layoutFlag, renderOpts, fontFamily, *animateIntervalFlag, inputPath, outputPath, "", *bundleFlag, *forceAppendixFlag, pw.Page)
 	if err != nil {
 		if written {
 			return fmt.Errorf("failed to fully compile (partial render written): %w", err)
@@ -366,7 +366,7 @@ func LayoutResolver(ctx context.Context, ms *xmain.State, plugins []d2plugin.Plu
 	}
 }
 
-func compile(ctx context.Context, ms *xmain.State, plugins []d2plugin.Plugin, layout *string, renderOpts d2svg.RenderOpts, fontFamily *d2fonts.FontFamily, animateInterval int64, inputPath, outputPath string, bundle, forceAppendix bool, page playwright.Page) (_ []byte, written bool, _ error) {
+func compile(ctx context.Context, ms *xmain.State, plugins []d2plugin.Plugin, layout *string, renderOpts d2svg.RenderOpts, fontFamily *d2fonts.FontFamily, animateInterval int64, inputPath, outputPath, boardPath string, bundle, forceAppendix bool, page playwright.Page) (_ []byte, written bool, _ error) {
 	start := time.Now()
 	input, err := ms.ReadPath(inputPath)
 	if err != nil {
@@ -500,7 +500,12 @@ func compile(ctx context.Context, ms *xmain.State, plugins []d2plugin.Plugin, la
 			}
 		}
 
-		boards, err := render(ctx, ms, compileDur, plugin, renderOpts, inputPath, outputPath, bundle, forceAppendix, page, ruler, diagram)
+		board := diagram.GetBoard(boardPath)
+		if board == nil {
+			return nil, false, fmt.Errorf("Diagram with path %s not found", boardPath)
+		}
+
+		boards, err := render(ctx, ms, compileDur, plugin, renderOpts, inputPath, outputPath, bundle, forceAppendix, page, ruler, board)
 		if err != nil {
 			return nil, false, err
 		}
diff --git a/d2cli/static/watch.js b/d2cli/static/watch.js
index a95403971..9da3e630a 100644
--- a/d2cli/static/watch.js
+++ b/d2cli/static/watch.js
@@ -9,7 +9,7 @@ function init(reconnectDelay) {
 
   const devMode = document.body.dataset.d2DevMode === "true";
   const ws = new WebSocket(
-    `ws://${window.location.host}${window.location.pathname}watch`
+    `ws://${window.location.host}/watch`
   );
   let isInit = true;
   let ratio;
@@ -28,7 +28,7 @@ function init(reconnectDelay) {
       // we can't just set `d2SVG.innerHTML = msg.svg` need to parse this as xml not html
       const parsedXML = new DOMParser().parseFromString(msg.svg, "text/xml");
       d2SVG.replaceChildren(parsedXML.documentElement);
-      changeFavicon("./static/favicon.ico");
+      changeFavicon("/static/favicon.ico");
       const svgEl = d2SVG.querySelector("#d2-svg");
       // just use inner SVG in watch mode
       svgEl.parentElement.replaceWith(svgEl);
@@ -60,7 +60,7 @@ function init(reconnectDelay) {
     if (msg.err) {
       d2ErrDiv.innerText = msg.err;
       d2ErrDiv.style.display = "block";
-      changeFavicon("./static/favicon-err.ico");
+      changeFavicon("/static/favicon-err.ico");
       d2ErrDiv.scrollIntoView();
     }
   };
diff --git a/d2cli/watch.go b/d2cli/watch.go
index 0fefabd61..b370a4d16 100644
--- a/d2cli/watch.go
+++ b/d2cli/watch.go
@@ -12,6 +12,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 	"sync"
 	"time"
 
@@ -49,6 +50,7 @@ type watcherOpts struct {
 	port            string
 	inputPath       string
 	outputPath      string
+	boardPath       string
 	pwd             string
 	bundle          bool
 	forceAppendix   bool
@@ -362,7 +364,7 @@ func (w *watcher) compileLoop(ctx context.Context) error {
 			w.pw = newPW
 		}
 
-		svg, _, err := compile(ctx, w.ms, w.plugins, w.layout, w.renderOpts, w.fontFamily, w.animateInterval, w.inputPath, w.outputPath, w.bundle, w.forceAppendix, w.pw.Page)
+		svg, _, err := compile(ctx, w.ms, w.plugins, w.layout, w.renderOpts, w.fontFamily, w.animateInterval, w.inputPath, w.outputPath, w.boardPath, w.bundle, w.forceAppendix, w.pw.Page)
 		errs := ""
 		if err != nil {
 			if len(svg) > 0 {
@@ -430,15 +432,23 @@ func (w *watcher) handleRoot(hw http.ResponseWriter, r *http.Request) {
 	<meta charset="UTF-8">
 	<meta name="viewport" content="width=device-width, initial-scale=1.0">
 	<title>%s</title>
-	<script src="./static/watch.js"></script>
-	<link rel="stylesheet" href="./static/watch.css">
-	<link id="favicon" rel="icon" href="./static/favicon.ico">
+	<script src="/static/watch.js"></script>
+	<link rel="stylesheet" href="/static/watch.css">
+	<link id="favicon" rel="icon" href="/static/favicon.ico">
 </head>
 <body data-d2-dev-mode=%t>
 	<div id="d2-err" style="display: none"></div>
 	<div id="d2-svg-container"></div>
 </body>
 </html>`, filepath.Base(w.outputPath), w.devMode)
+
+	// if path is "/x.svg", we just want "x"
+	split := strings.Split(strings.TrimPrefix(r.URL.Path, "/"), ".")
+	boardPath := strings.Join(split[:len(split)-1], ".")
+	if boardPath != w.boardPath {
+		w.boardPath = boardPath
+		w.requestCompile()
+	}
 }
 
 func (w *watcher) handleWatch(hw http.ResponseWriter, r *http.Request) error {
diff --git a/d2target/d2target.go b/d2target/d2target.go
index 368e4c1a7..7bbfb63f8 100644
--- a/d2target/d2target.go
+++ b/d2target/d2target.go
@@ -6,6 +6,7 @@ import (
 	"hash/fnv"
 	"math"
 	"net/url"
+	"os"
 	"strings"
 
 	"oss.terrastruct.com/util-go/go2"
@@ -72,6 +73,66 @@ type Diagram struct {
 	Steps     []*Diagram `json:"steps,omitempty"`
 }
 
+// boardPath comes in the form of "x/layers/z/scenarios/a"
+// or in the form of "layers/z/scenarios/a"
+func (d *Diagram) GetBoard(boardPath string) *Diagram {
+	path := strings.Split(boardPath, string(os.PathSeparator))
+	if len(path) == 0 || len(boardPath) == 0 {
+		return d
+	}
+
+	head := path[0]
+
+	if head == "index" {
+		return d
+	}
+
+	switch head {
+	case "layers", "scenarios", "steps":
+		if len(path) < 2 {
+			return nil
+		}
+	}
+
+	switch head {
+	case "layers":
+		for _, b := range d.Layers {
+			if b.Name == path[1] {
+				return b.GetBoard(strings.Join(path[2:], string(os.PathSeparator)))
+			}
+		}
+	case "scenarios":
+		for _, b := range d.Scenarios {
+			if b.Name == path[1] {
+				return b.GetBoard(strings.Join(path[2:], string(os.PathSeparator)))
+			}
+		}
+	case "steps":
+		for _, b := range d.Steps {
+			if b.Name == path[1] {
+				return b.GetBoard(strings.Join(path[2:], string(os.PathSeparator)))
+			}
+		}
+	}
+
+	for _, b := range d.Layers {
+		if b.Name == head {
+			return b.GetBoard(strings.Join(path[1:], string(os.PathSeparator)))
+		}
+	}
+	for _, b := range d.Scenarios {
+		if b.Name == head {
+			return b.GetBoard(strings.Join(path[1:], string(os.PathSeparator)))
+		}
+	}
+	for _, b := range d.Steps {
+		if b.Name == head {
+			return b.GetBoard(strings.Join(path[1:], string(os.PathSeparator)))
+		}
+	}
+	return nil
+}
+
 func (diagram Diagram) Bytes() ([]byte, error) {
 	b1, err := json.Marshal(diagram.Shapes)
 	if err != nil {