diff --git a/.github/workflows/check.yaml b/.github/workflows/check.yaml
index 110c11b0..fd162834 100644
--- a/.github/workflows/check.yaml
+++ b/.github/workflows/check.yaml
@@ -33,6 +33,11 @@ jobs:
       - name: Check Python formatting
         run: uvx ruff format --check .  --config pyproject.toml
 
+      - name: Check Scenarios formatting
+        run: |
+          npm ci
+          npx prettier --check "scenarios/**/*.{toml,json,yaml}"
+
   typos:
     runs-on: ubuntu-latest
     name: Check typos
diff --git a/.prettierrc b/.prettierrc
new file mode 100644
index 00000000..511892dc
--- /dev/null
+++ b/.prettierrc
@@ -0,0 +1,3 @@
+{
+  "plugins": ["prettier-plugin-toml"]
+}
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index cdc08661..91568d27 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -42,3 +42,12 @@ manually back out the change. See [this comment][index-incorrect-snapshot] for
 an example.
 
 [index-incorrect-snapshot]: https://github.com/astral-sh/packse/pull/175#issuecomment-2056964089
+
+## Formatting Scenarios
+
+This step requires NodeJS installed.
+
+```
+npm install
+npx prettier --write "scenarios/**/*.{toml,json,yaml}"
+```
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 00000000..c40b05d4
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,65 @@
+{
+  "name": "packse",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "devDependencies": {
+        "prettier": "^3.3.3",
+        "prettier-plugin-toml": "^2.0.1"
+      }
+    },
+    "node_modules/@taplo/core": {
+      "version": "0.1.1",
+      "resolved": "https://registry.npmjs.org/@taplo/core/-/core-0.1.1.tgz",
+      "integrity": "sha512-BG/zLGf5wiNXGEVPvUAAX/4ilB3PwDUY2o0MV0y47mZbDZ9ad9UK/cIQsILat3bqbPJsALVbU6k3cskNZ3vAQg==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@taplo/lib": {
+      "version": "0.4.0-alpha.2",
+      "resolved": "https://registry.npmjs.org/@taplo/lib/-/lib-0.4.0-alpha.2.tgz",
+      "integrity": "sha512-DV/Re3DPVY+BhBtLZ3dmP4mP6YMLSsgq9qGLXwOV38lvNF/fBlgvQswzlXmzCEefL/3q2eMoefZpOI/+GLuCNA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@taplo/core": "^0.1.0"
+      }
+    },
+    "node_modules/prettier": {
+      "version": "3.3.3",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.3.3.tgz",
+      "integrity": "sha512-i2tDNA0O5IrMO757lfrdQZCc2jPNDVntV0m/+4whiDfWaTKfMNgR7Qz0NAeGz/nRqF4m5/6CLzbP4/liHt12Ew==",
+      "dev": true,
+      "license": "MIT",
+      "bin": {
+        "prettier": "bin/prettier.cjs"
+      },
+      "engines": {
+        "node": ">=14"
+      },
+      "funding": {
+        "url": "https://github.com/prettier/prettier?sponsor=1"
+      }
+    },
+    "node_modules/prettier-plugin-toml": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/prettier-plugin-toml/-/prettier-plugin-toml-2.0.1.tgz",
+      "integrity": "sha512-99z1YOkViECHtXQjGIigd3talI/ybUI1zB3yniAwUrlWBXupNXThB1hM6bwSMUEj2/+tomTlMtT98F5t4s8IWA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@taplo/lib": "^0.4.0-alpha.2"
+      },
+      "engines": {
+        "node": ">=16.0.0"
+      },
+      "funding": {
+        "url": "https://opencollective.com/unts"
+      },
+      "peerDependencies": {
+        "prettier": "^3.0.3"
+      }
+    }
+  }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 00000000..521c394c
--- /dev/null
+++ b/package.json
@@ -0,0 +1,6 @@
+{
+  "devDependencies": {
+    "prettier": "^3.3.3",
+    "prettier-plugin-toml": "^2.0.1"
+  }
+}
diff --git a/scenarios/examples/example.json b/scenarios/examples/example.json
index 67844d5e..56fc546b 100644
--- a/scenarios/examples/example.json
+++ b/scenarios/examples/example.json
@@ -1,39 +1,33 @@
 {
-    "name": "example",
-    "description": "This is an example scenario, in which the user depends on a single package `a` which requires `b`.",
-    "expected": {
-        "satisfiable": true,
-        "packages": {
-            "a": "1.0.0",
-            "b": "2.0.0"
-        },
-        "explanation": "The latest valid version of `b` should be installed. `b==3.0.0` is not valid because it requires `c` which does not exist."
+  "name": "example",
+  "description": "This is an example scenario, in which the user depends on a single package `a` which requires `b`.",
+  "expected": {
+    "satisfiable": true,
+    "packages": {
+      "a": "1.0.0",
+      "b": "2.0.0"
     },
-    "root": {
-        "requires": [
-            "a"
-        ]
+    "explanation": "The latest valid version of `b` should be installed. `b==3.0.0` is not valid because it requires `c` which does not exist."
+  },
+  "root": {
+    "requires": ["a"]
+  },
+  "packages": {
+    "a": {
+      "versions": {
+        "1.0.0": {
+          "requires": ["b>1.0.0"]
+        }
+      }
     },
-    "packages": {
-        "a": {
-            "versions": {
-                "1.0.0": {
-                    "requires": [
-                        "b>1.0.0"
-                    ]
-                }
-            }
-        },
-        "b": {
-            "versions": {
-                "1.0.0": {},
-                "2.0.0": {},
-                "3.0.0": {
-                    "requires": [
-                        "c"
-                    ]
-                }
-            }
+    "b": {
+      "versions": {
+        "1.0.0": {},
+        "2.0.0": {},
+        "3.0.0": {
+          "requires": ["c"]
         }
+      }
     }
+  }
 }
diff --git a/scenarios/examples/example.toml b/scenarios/examples/example.toml
index c813236f..576ff5cc 100644
--- a/scenarios/examples/example.toml
+++ b/scenarios/examples/example.toml
@@ -5,19 +5,19 @@ description = "This is an example scenario written in TOML, in which the user de
 satisfiable = true
 explanation = "The latest valid version of `b` should be installed. `b==3.0.0` is not valid because it requires `c` which does not exist."
 
-  [expected.packages]
-  a = "1.0.0"
-  b = "2.0.0"
+[expected.packages]
+a = "1.0.0"
+b = "2.0.0"
 
 [root]
-requires = [ "a" ]
+requires = ["a"]
 
 [packages.a.versions."1.0.0"]
-requires = [ "b>1.0.0" ]
+requires = ["b>1.0.0"]
 
 [packages.b.versions]
-"1.0.0" = { }
-"2.0.0" = { }
+"1.0.0" = {}
+"2.0.0" = {}
 
-  [packages.b.versions."3.0.0"]
-  requires = [ "c" ]
+[packages.b.versions."3.0.0"]
+requires = ["c"]
diff --git a/scenarios/examples/example.yaml b/scenarios/examples/example.yaml
index f9a0aba3..a9279468 100644
--- a/scenarios/examples/example.yaml
+++ b/scenarios/examples/example.yaml
@@ -1,26 +1,28 @@
 - name: example-yaml
-  description: This is an example scenario written in YAML, in which the user depends on a single
-    package `a` which requires `b`.
+  description:
+    This is an example scenario written in YAML, in which the user depends on a
+    single package `a` which requires `b`.
   expected:
     satisfiable: true
     packages:
       a: 1.0.0
       b: 2.0.0
-    explanation: The latest valid version of `b` should be installed. `b==3.0.0` is
-      not valid because it requires `c` which does not exist.
+    explanation:
+      The latest valid version of `b` should be installed. `b==3.0.0` is not
+      valid because it requires `c` which does not exist.
   root:
     requires:
-    - a
+      - a
   packages:
     a:
       versions:
         1.0.0:
           requires:
-          - b>1.0.0
+            - b>1.0.0
     b:
       versions:
         1.0.0: {}
         2.0.0: {}
         3.0.0:
           requires:
-          - c
+            - c