diff --git a/CHANGELOG.md b/CHANGELOG.md
index c32953b..53bd21e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Changed
+
+- Raised the development Node.js requirement to `^22.22.2 || ^24.15.0 || >=26.0.0`, following the
+  jsdom 30 upgrade. This affects the dev toolchain only; the built server and packaged binaries
+  still target Node 22.
+
 ### Fixed
 
 - The right-click menu in the file browser now opens at the pointer instead of the row's
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 94c5f76..7bb1c74 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -6,8 +6,8 @@ when you open a pull request.
 
 ## Prerequisites
 
-- **Node.js `^20.19` or `>=22.12`** (required by the Vite and oxlint dev tooling; the project
-  builds and packages against Node 22).
+- **Node.js `^22.22.2`, `^24.15.0`, or `>=26.0.0`** (required by the jsdom and Vite dev tooling;
+  the project builds and packages against Node 22).
 - **rclone** on your `PATH`, or point Siphon at a binary with the `RCLONE_PATH` environment
   variable. rclone does the actual transfer work; Siphon is the front end.
 - An SFTP server to test against (any box you can reach over SSH works).
diff --git a/package-lock.json b/package-lock.json
index 621ab9f..4c88ba8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -37,7 +37,7 @@
         "vitest": "^4.1.11"
       },
       "engines": {
-        "node": "^20.19.0 || >=22.12.0"
+        "node": "^22.22.2 || ^24.15.0 || >=26.0.0"
       }
     },
     "node_modules/@adobe/css-tools": {
diff --git a/package.json b/package.json
index 503fefe..cc72608 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "url": "https://github.com/dentifrag/siphon/issues"
   },
   "engines": {
-    "node": "^20.19.0 || >=22.12.0"
+    "node": "^22.22.2 || ^24.15.0 || >=26.0.0"
   },
   "main": "dist-server/index.cjs",
   "scripts": {