diff --git a/tests/projects-born-data.test.mjs b/tests/projects-born-data.test.mjs
new file mode 100644
index 00000000..4edf11f7
--- /dev/null
+++ b/tests/projects-born-data.test.mjs
@@ -0,0 +1,125 @@
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import test from 'node:test';
+
+// Contract test for the checked-in data file, not for a script. The corpus is
+// rendered directly by src/components/ProjectsBorn/index.js and has no
+// validate-*.mjs of its own, so these assertions are the only guard on it.
+const DATA_PATH = fileURLToPath(
+  new URL('../data/projects-born.json', import.meta.url),
+);
+
+const REQUIRED_FIELDS = ['name', 'origin', 'description', 'url'];
+
+const raw = readFileSync(DATA_PATH, 'utf8');
+
+function describeEntry(entry, index) {
+  const label =
+    typeof entry?.name === 'string' && entry.name ? entry.name : `#${index}`;
+  return `entry ${label}`;
+}
+
+test('data/projects-born.json parses as JSON', () => {
+  assert.doesNotThrow(() => JSON.parse(raw));
+});
+
+const projects = JSON.parse(raw);
+
+test('is a non-empty array', () => {
+  assert.ok(Array.isArray(projects), 'expected the top level to be an array');
+  assert.ok(projects.length > 0, 'expected at least one project');
+});
+
+test('every entry is a plain object', () => {
+  projects.forEach((entry, index) => {
+    assert.equal(
+      Object.prototype.toString.call(entry),
+      '[object Object]',
+      `${describeEntry(entry, index)} is not an object`,
+    );
+  });
+});
+
+test('every entry has all required fields as non-empty strings', () => {
+  projects.forEach((entry, index) => {
+    for (const field of REQUIRED_FIELDS) {
+      const value = entry[field];
+      assert.equal(
+        typeof value,
+        'string',
+        `${describeEntry(entry, index)} has a non-string ${field}`,
+      );
+      assert.notEqual(
+        value.trim(),
+        '',
+        `${describeEntry(entry, index)} has an empty ${field}`,
+      );
+    }
+  });
+});
+
+test('no entry carries fields the component does not render', () => {
+  projects.forEach((entry, index) => {
+    const unexpected = Object.keys(entry).filter(
+      (key) => !REQUIRED_FIELDS.includes(key),
+    );
+    assert.deepEqual(
+      unexpected,
+      [],
+      `${describeEntry(entry, index)} has unrecognised field(s): ${unexpected.join(', ')}`,
+    );
+  });
+});
+
+test('name values are unique because name is the React list key', () => {
+  const seen = new Map();
+  const duplicates = [];
+  projects.forEach((entry) => {
+    if (seen.has(entry.name)) duplicates.push(entry.name);
+    seen.set(entry.name, true);
+  });
+  assert.deepEqual(
+    duplicates,
+    [],
+    `duplicate project name(s): ${duplicates.join(', ')}`,
+  );
+});
+
+test('every url is an absolute https URL', () => {
+  projects.forEach((entry, index) => {
+    let parsed;
+    assert.doesNotThrow(
+      () => {
+        parsed = new URL(entry.url);
+      },
+      `${describeEntry(entry, index)} has an unparseable url: ${entry.url}`,
+    );
+    assert.equal(
+      parsed.protocol,
+      'https:',
+      `${describeEntry(entry, index)} uses ${parsed.protocol} rather than https:`,
+    );
+    assert.notEqual(
+      parsed.hostname,
+      '',
+      `${describeEntry(entry, index)} has a url with no host`,
+    );
+  });
+});
+
+test('no field carries leading or trailing whitespace', () => {
+  projects.forEach((entry, index) => {
+    for (const field of REQUIRED_FIELDS) {
+      assert.equal(
+        entry[field],
+        entry[field].trim(),
+        `${describeEntry(entry, index)} has padded whitespace in ${field}`,
+      );
+    }
+  });
+});
+
+test('the file is formatted with a trailing newline', () => {
+  assert.ok(raw.endsWith('\n'), 'expected a trailing newline');
+});