diff --git a/src/scripts/sync/generate-projects-diff-actions.ts b/src/scripts/sync/generate-projects-diff-actions.ts
new file mode 100644
index 00000000..ded81d4a
--- /dev/null
+++ b/src/scripts/sync/generate-projects-diff-actions.ts
@@ -0,0 +1,33 @@
+import type { SnykProject } from '../../lib/types';
+
+export function generateProjectDiffActions(
+  repoManifests: string[],
+  snykMonitoredProjects: SnykProject[],
+): {
+  import: string[];
+  deactivate: SnykProject[];
+} {
+  const filesToImport: string[] = [];
+  const deactivate: SnykProject[] = [];
+
+  // any files in the repo, not in Snyk already should be
+  // imported
+  for (const manifest of repoManifests) {
+    const snykProjectManifests = snykMonitoredProjects.map(
+      (p) => p.name.split(':')[1],
+    );
+    if (!snykProjectManifests.includes(manifest)) {
+      filesToImport.push(manifest);
+    }
+  }
+
+  // any files in Snyk, not found in the repo should have the
+  // related project de-activated
+  for (const project of snykMonitoredProjects) {
+    if (!repoManifests.includes(project.name.split(':')[1])) {
+      deactivate.push(project);
+    }
+  }
+
+  return { import: filesToImport, deactivate };
+}
diff --git a/test/scripts/sync/generate-projects-diff-actions.spec.ts b/test/scripts/sync/generate-projects-diff-actions.spec.ts
new file mode 100644
index 00000000..52f221a6
--- /dev/null
+++ b/test/scripts/sync/generate-projects-diff-actions.spec.ts
@@ -0,0 +1,67 @@
+import { generateProjectDiffActions } from '../../../src/scripts/sync/generate-projects-diff-actions';
+import type { SnykProject } from '../../../src/lib/types';
+
+describe('generateProjectDiffActions', () => {
+  it('identifies correctly the diff between files in the repo vs monitored in Snyk', async () => {
+    // Arrange
+    const projects: SnykProject[] = [
+      {
+        name: 'snyk/goof:todo/package.json',
+        id: 'af137b96-6966-46c1-826b-2e79ac49bbxx',
+        created: '2018-10-29T09:50:54.014Z',
+        origin: 'github',
+        type: 'npm',
+        branch: 'master',
+      },
+      {
+        name: 'snyk/goof:src/Dockerfile',
+        id: 'af137b96-6966-46c1-826b-2e79ac49bbxx',
+        created: '2018-10-29T09:50:54.014Z',
+        origin: 'github',
+        type: 'npm',
+        branch: 'master',
+      },
+    ];
+    // Act
+    const res = await generateProjectDiffActions(
+      ['package.json', 'path/to/build.gradle', 'src/Dockerfile'],
+      projects,
+    );
+
+    // Assert
+    expect(res).toStrictEqual({
+      import: ['package.json', 'path/to/build.gradle'],
+      deactivate: [
+        {
+          name: 'snyk/goof:todo/package.json',
+          id: 'af137b96-6966-46c1-826b-2e79ac49bbxx',
+          created: '2018-10-29T09:50:54.014Z',
+          origin: 'github',
+          type: 'npm',
+          branch: 'master',
+        },
+      ],
+    });
+  });
+  it('no changes needed', async () => {
+    // Arrange
+    const projects: SnykProject[] = [
+      {
+        name: 'snyk/goof:package.json',
+        id: 'af137b96-6966-46c1-826b-2e79ac49bbxx',
+        created: '2018-10-29T09:50:54.014Z',
+        origin: 'github',
+        type: 'npm',
+        branch: 'master',
+      },
+    ];
+    // Act
+    const res = await generateProjectDiffActions(['package.json'], projects);
+
+    // Assert
+    expect(res).toStrictEqual({
+      import: [],
+      deactivate: [],
+    });
+  });
+});