diff --git a/lib/__tests__/jsonLd.test.ts b/lib/__tests__/jsonLd.test.ts
new file mode 100644
index 0000000..990cfa6
--- /dev/null
+++ b/lib/__tests__/jsonLd.test.ts
@@ -0,0 +1,51 @@
+import { describe, it, expect } from "vitest";
+import { getTool, TOOLS, SITE_URL } from "../tools";
+import { toolJsonLd, breadcrumbJsonLd, faqJsonLd, homeJsonLd } from "../jsonLd";
+
+// jwt-decoder always ships with FAQs, so it exercises every builder without
+// coupling the test to copy that changes across branches.
+const jwt = getTool("jwt-decoder")!;
+
+describe("toolJsonLd", () => {
+  it("marks the tool as a free, English SoftwareApplication", () => {
+    const ld = toolJsonLd(jwt);
+    expect(ld["@type"]).toBe("SoftwareApplication");
+    expect(ld.inLanguage).toBe("en");
+    expect(ld.isAccessibleForFree).toBe(true);
+    expect(ld.url).toBe(`${SITE_URL}${jwt.path}`);
+    expect(ld.offers).toMatchObject({ price: "0", priceCurrency: "USD" });
+  });
+});
+
+describe("breadcrumbJsonLd", () => {
+  it("is a two-level Home > Tool trail with no item on the current page", () => {
+    const ld = breadcrumbJsonLd(jwt);
+    expect(ld.itemListElement).toHaveLength(2);
+    expect(ld.itemListElement[0]).toMatchObject({ position: 1, name: "Home", item: SITE_URL });
+    expect(ld.itemListElement[1].position).toBe(2);
+    expect(ld.itemListElement[1]).not.toHaveProperty("item");
+  });
+});
+
+describe("faqJsonLd", () => {
+  it("maps every FAQ to a Question/Answer pair", () => {
+    const ld = faqJsonLd(jwt);
+    expect(ld["@type"]).toBe("FAQPage");
+    expect(ld.mainEntity).toHaveLength(jwt.faqs.length);
+    expect(ld.mainEntity[0]).toMatchObject({
+      "@type": "Question",
+      name: jwt.faqs[0].q,
+      acceptedAnswer: { "@type": "Answer", text: jwt.faqs[0].a },
+    });
+  });
+});
+
+describe("homeJsonLd", () => {
+  it("emits Organization, an English WebSite, and an ItemList of every tool", () => {
+    const graph = homeJsonLd()["@graph"];
+    const byType = (t: string) => graph.find((n) => n["@type"] === t) as Record<string, unknown> | undefined;
+    expect(byType("Organization")).toBeTruthy();
+    expect(byType("WebSite")?.inLanguage).toBe("en");
+    expect((byType("ItemList")?.itemListElement as unknown[]).length).toBe(TOOLS.length);
+  });
+});
diff --git a/lib/jsonLd.ts b/lib/jsonLd.ts
index a36cd6d..678e04c 100644
--- a/lib/jsonLd.ts
+++ b/lib/jsonLd.ts
@@ -31,6 +31,12 @@ export function toolJsonLd(tool: Tool) {
     operatingSystem: "Any (Browser)",
     description: tool.jsonLdDescription,
     url: `${SITE_URL}${tool.path}`,
+    inLanguage: "en",
+    // Every tool is free and needs no account, so this is truthful and helps
+    // Google understand the offer. No datePublished — we have no authoritative
+    // publish date to state, and fabricating one is against the same policy that
+    // keeps aggregateRating off these nodes.
+    isAccessibleForFree: true,
     offers: { "@type": "Offer", price: "0", priceCurrency: "USD" },
     publisher: { "@type": "Organization", name: "CODERCOPS", url: "https://www.codercops.com" },
   };
@@ -80,6 +86,7 @@ export function homeJsonLd() {
         url: SITE_URL,
         name: "CODERCOPS Tools",
         description: "Free, fast, privacy-first developer tools that run entirely in your browser.",
+        inLanguage: "en",
         publisher: { "@id": ORG_ID },
       },
       {