diff --git a/javascript/.nvmrc b/javascript/.nvmrc
deleted file mode 100644
index 1a2f5bd..0000000
--- a/javascript/.nvmrc
+++ /dev/null
@@ -1 +0,0 @@
-lts/*
\ No newline at end of file
diff --git a/javascript/.tool-versions b/javascript/.tool-versions
new file mode 100644
index 0000000..e2d8fff
--- /dev/null
+++ b/javascript/.tool-versions
@@ -0,0 +1,2 @@
+node 22
+yarn 3
diff --git a/javascript/README.md b/javascript/README.md
index 14b35ca..a54a207 100644
--- a/javascript/README.md
+++ b/javascript/README.md
@@ -1,14 +1,30 @@
-# Javascript
+# JavaScript
 
-Skeleton project for Javascript with Jest for testing.
+Skeleton project for JavaScript.
 
-## Usage
-- `./script/setup` to install dependencies
-- `./script/test` to run the tests
+## Prerequisites
+
+The toolchain this project needs is declared in [`.tool-versions`](./.tool-versions):
+
+```
+node 22
+yarn 3
+```
 
+Install those however you prefer, as long as they end up on your `PATH`. The quickest route is
+[mise](https://mise.jdx.dev/), which reads the file for you:
+
+```sh
+mise install
+```
+
+## Usage
+- `./script/setup` to fetch dependencies
+- `./script/test` to run the tests, or `./script/test --watch` to re-run them on every change
+- `./script/start` to run the app
 
 ## Structure
 - Code located in [`index.js`](./src/index.js)
 - Tests located in [`index.test.js`](./src/index.test.js)
 
-However, you're free to organise your code as you like. 
+However, you're free to organise your code as you like.
diff --git a/javascript/package.json b/javascript/package.json
index 46bc4fb..2c21315 100644
--- a/javascript/package.json
+++ b/javascript/package.json
@@ -5,6 +5,7 @@
         "jest": "^29.5.0"
     },
     "scripts": {
+        "start": "node src/index.js",
         "test": "jest"
     }
 }
diff --git a/javascript/script/setup b/javascript/script/setup
index d302646..e2cee61 100755
--- a/javascript/script/setup
+++ b/javascript/script/setup
@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
-set -e
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
 
 yarn
diff --git a/javascript/script/start b/javascript/script/start
new file mode 100755
index 0000000..61c9770
--- /dev/null
+++ b/javascript/script/start
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+cd "$(dirname "${BASH_SOURCE[0]}")/.."
+
+yarn start