diff --git a/client/markdown_renderer/html_render.ts b/client/markdown_renderer/html_render.ts
index 49a1175c..b831fd82 100644
--- a/client/markdown_renderer/html_render.ts
+++ b/client/markdown_renderer/html_render.ts
@@ -19,7 +19,7 @@ export function htmlEscape(s: string): string {
     .replace(/</g, "&lt;")
     .replace(/>/g, "&gt;")
     .replace(/"/g, "&quot;")
-    .replace(/\n/g, "<br>");
+    .replace(/\n/g, "<br/>");
 
   let oldS = s;
   do {
diff --git a/client/markdown_renderer/markdown_render.test.ts b/client/markdown_renderer/markdown_render.test.ts
index e9c892cf..160e2194 100644
--- a/client/markdown_renderer/markdown_render.test.ts
+++ b/client/markdown_renderer/markdown_render.test.ts
@@ -99,7 +99,7 @@ test("Smart hard break test", () => {
     smartHardBreak: true,
   });
   expect(html).toEqual(
-    `<span class="p"><strong>Hello</strong><br><em>world!</em></span>`,
+    `<span class="p"><strong>Hello</strong><br/><em>world!</em></span>`,
   );
 
   const example2 = `This is going to be a text. With a new line.
diff --git a/client/space_lua/render_lua_markdown.test.ts b/client/space_lua/render_lua_markdown.test.ts
index f81cf49f..be7d2780 100644
--- a/client/space_lua/render_lua_markdown.test.ts
+++ b/client/space_lua/render_lua_markdown.test.ts
@@ -331,7 +331,7 @@ test("nested scalar array in table cell renders as br-separated lines", async ()
   await tbl.rawSet(1, row);
 
   const r = renderResultToMarkdown(tbl);
-  expect(r.markdown).toContain("aaa<br>bbb");
+  expect(r.markdown).toContain("aaa<br/>bbb");
 });
 
 // ── Markdown in cell values ─────────────────────────────────────────
@@ -427,7 +427,7 @@ test("e2e: scalar list renders each item on its own line", async () => {
   await tbl.rawSet(3, "third");
 
   expect(toHtml(tbl)).toBe(
-    '<span class="p">first<br>second<br>third</span>',
+    '<span class="p">first<br/>second<br/>third</span>',
   );
 });
 
@@ -438,7 +438,7 @@ test("e2e: list with wiki links", async () => {
 
   expect(toHtml(tbl)).toBe(
     '<span class="p">' +
-      '<a href="/PageA" class="wiki-link" data-ref="PageA">PageA</a><br>' +
+      '<a href="/PageA" class="wiki-link" data-ref="PageA">PageA</a><br/>' +
       '<a href="/PageB" class="wiki-link" data-ref="PageB">PageB</a></span>',
   );
 });
@@ -487,7 +487,7 @@ test("e2e: nested array in table cell renders as br-separated lines", async () =
   expect(toHtml(tbl)).toBe(
     "<table><thead><tr><th>name</th><th>hello</th></tr></thead><tbody>" +
       '<tr><td data-table-cell-type="string">Sup</td>' +
-      '<td data-table-cell-type="array">aaa<br>bbb</br></td></tr></tbody></table>',
+      '<td data-table-cell-type="array">aaa<br/>bbb</td></tr></tbody></table>',
   );
 });
 
diff --git a/client/space_lua/render_lua_markdown.ts b/client/space_lua/render_lua_markdown.ts
index 21e2ddec..55f6b124 100644
--- a/client/space_lua/render_lua_markdown.ts
+++ b/client/space_lua/render_lua_markdown.ts
@@ -204,7 +204,7 @@ function renderArrayToMarkdown(items: any[]): string {
 }
 
 function renderArrayToHtmlLines(items: any[]): string {
-  return items.map((item) => renderCellContent(item)).join("<br>");
+  return items.map((item) => renderCellContent(item)).join("<br/>");
 }
 
 /**