diff --git a/src/components/SettingsTab.test.tsx b/src/components/SettingsTab.test.tsx
new file mode 100644
index 0000000..c48b4a9
--- /dev/null
+++ b/src/components/SettingsTab.test.tsx
@@ -0,0 +1,162 @@
+/**
+ * @vitest-environment jsdom
+ */
+import { render, screen, fireEvent } from "@testing-library/react";
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { SettingsTab } from "./SettingsTab";
+import { MAIN_BLOCKS, DETAIL_OPTIONS } from "@/lib/cardGeneratorConstants";
+import type { CardDisplayOptions } from "@/lib/cardSettings";
+
+describe("SettingsTab", () => {
+  const mockIsBlockVisible = vi.fn();
+  const mockToggleMainBlockVisibility = vi.fn();
+  const mockToggleDisplayOption = vi.fn();
+
+  const defaultDisplayOptions: CardDisplayOptions = {
+    showAvatar: true,
+    showBio: false,
+    showStats: true,
+    showLanguage: false,
+    showRepos: true,
+    showCompany: false,
+    showLocation: true,
+    showWebsite: false,
+    showTwitter: true,
+    showJoinedDate: false,
+    showTopics: true,
+    showContributionBreakdown: false,
+    showStreaks: true,
+    showInterests: false,
+    showActivityBreakdown: true,
+  };
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("renders all MAIN_BLOCKS and DETAIL_OPTIONS", () => {
+    render(
+      <SettingsTab
+        isBlockVisible={mockIsBlockVisible}
+        toggleMainBlockVisibility={mockToggleMainBlockVisibility}
+        displayOptions={defaultDisplayOptions}
+        toggleDisplayOption={mockToggleDisplayOption}
+      />
+    );
+
+    MAIN_BLOCKS.forEach((block) => {
+      expect(screen.getByLabelText(block.label)).toBeDefined();
+    });
+
+    DETAIL_OPTIONS.forEach((option) => {
+      expect(screen.getByLabelText(option.label)).toBeDefined();
+    });
+  });
+
+  it("reflects checked state for blocks and options correctly", () => {
+    // Let's set some specific mocks to test truthy vs falsy returns
+    mockIsBlockVisible.mockImplementation((id) => id === "profile" || id === "heatmap");
+
+    const customDisplayOptions = {
+      ...defaultDisplayOptions,
+      showAvatar: true, // Should be checked
+      showBio: false,   // Should not be checked
+    };
+
+    render(
+      <SettingsTab
+        isBlockVisible={mockIsBlockVisible}
+        toggleMainBlockVisibility={mockToggleMainBlockVisibility}
+        displayOptions={customDisplayOptions}
+        toggleDisplayOption={mockToggleDisplayOption}
+      />
+    );
+
+    const profileBlock = screen.getByLabelText(
+      MAIN_BLOCKS.find((b) => b.id === "profile")!.label
+    ) as HTMLInputElement;
+    expect(profileBlock.checked).toBe(true);
+
+    const contributionsBlock = screen.getByLabelText(
+      MAIN_BLOCKS.find((b) => b.id === "contributions")!.label
+    ) as HTMLInputElement;
+    expect(contributionsBlock.checked).toBe(false);
+
+    const avatarOption = screen.getByLabelText(
+      DETAIL_OPTIONS.find((o) => o.key === "showAvatar")!.label
+    ) as HTMLInputElement;
+    expect(avatarOption.checked).toBe(true);
+
+    const bioOption = screen.getByLabelText(
+      DETAIL_OPTIONS.find((o) => o.key === "showBio")!.label
+    ) as HTMLInputElement;
+    expect(bioOption.checked).toBe(false);
+  });
+
+  it("calls toggleMainBlockVisibility when a main block checkbox is clicked", () => {
+    mockIsBlockVisible.mockReturnValue(false);
+    render(
+      <SettingsTab
+        isBlockVisible={mockIsBlockVisible}
+        toggleMainBlockVisibility={mockToggleMainBlockVisibility}
+        displayOptions={defaultDisplayOptions}
+        toggleDisplayOption={mockToggleDisplayOption}
+      />
+    );
+
+    const profileBlock = screen.getByLabelText(
+      MAIN_BLOCKS.find((b) => b.id === "profile")!.label
+    );
+
+    fireEvent.click(profileBlock);
+
+    expect(mockToggleMainBlockVisibility).toHaveBeenCalledWith("profile");
+    expect(mockToggleMainBlockVisibility).toHaveBeenCalledTimes(1);
+  });
+
+  it("calls toggleDisplayOption when a detail option checkbox is clicked", () => {
+    mockIsBlockVisible.mockReturnValue(false);
+    render(
+      <SettingsTab
+        isBlockVisible={mockIsBlockVisible}
+        toggleMainBlockVisibility={mockToggleMainBlockVisibility}
+        displayOptions={defaultDisplayOptions}
+        toggleDisplayOption={mockToggleDisplayOption}
+      />
+    );
+
+    const avatarOption = screen.getByLabelText(
+      DETAIL_OPTIONS.find((o) => o.key === "showAvatar")!.label
+    );
+
+    fireEvent.click(avatarOption);
+
+    expect(mockToggleDisplayOption).toHaveBeenCalledWith("showAvatar");
+    expect(mockToggleDisplayOption).toHaveBeenCalledTimes(1);
+  });
+
+  it("defaults missing displayOptions to false", () => {
+    const optionsWithMissingKeys = {
+      showAvatar: true, // Only this is present
+    } as CardDisplayOptions;
+
+    render(
+      <SettingsTab
+        isBlockVisible={mockIsBlockVisible}
+        toggleMainBlockVisibility={mockToggleMainBlockVisibility}
+        displayOptions={optionsWithMissingKeys}
+        toggleDisplayOption={mockToggleDisplayOption}
+      />
+    );
+
+    const avatarOption = screen.getByLabelText(
+      DETAIL_OPTIONS.find((o) => o.key === "showAvatar")!.label
+    ) as HTMLInputElement;
+    expect(avatarOption.checked).toBe(true);
+
+    const bioOption = screen.getByLabelText(
+      DETAIL_OPTIONS.find((o) => o.key === "showBio")!.label
+    ) as HTMLInputElement;
+    expect(bioOption.checked).toBe(false); // Defaulted to false because it's missing in the provided object
+  });
+});
diff --git a/vitest.config.ts b/vitest.config.ts
index 9404856..6e7768d 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -21,6 +21,7 @@ export default defineConfig({
         "src/components/LanguageChart.tsx",
         "src/components/SkillsCard.tsx",
         "src/components/LayoutEditor.tsx",
+        "src/components/SettingsTab.tsx",
         "src/lib/rateLimit.ts",
         "src/app/api/og/[username]/route.tsx"
       ],