diff --git a/apps/api/src/routes/tools/color-blindness.ts b/apps/api/src/routes/tools/color-blindness.ts
new file mode 100644
index 00000000..ca6ed085
--- /dev/null
+++ b/apps/api/src/routes/tools/color-blindness.ts
@@ -0,0 +1,39 @@
+import { colorBlindness } from "@snapotter/image-engine";
+import type { FastifyInstance } from "fastify";
+import sharp from "sharp";
+import { z } from "zod";
+import { resolveOutputFormat } from "../../lib/output-format.js";
+import { createToolRoute } from "../tool-factory.js";
+
+const settingsSchema = z.object({
+  simulationType: z
+    .enum([
+      "protanopia",
+      "deuteranopia",
+      "tritanopia",
+      "protanomaly",
+      "deuteranomaly",
+      "tritanomaly",
+      "achromatopsia",
+      "blueConeMonochromacy",
+    ])
+    .default("deuteranomaly"),
+});
+
+export function registerColorBlindness(app: FastifyInstance) {
+  createToolRoute(app, {
+    toolId: "color-blindness",
+    settingsSchema,
+    process: async (inputBuffer, settings, filename) => {
+      const image = sharp(inputBuffer);
+      const result = await colorBlindness(image, { type: settings.simulationType });
+
+      const outputFormat = await resolveOutputFormat(inputBuffer, filename);
+      const buffer = await result
+        .toFormat(outputFormat.format, { quality: outputFormat.quality })
+        .toBuffer();
+
+      return { buffer, filename, contentType: outputFormat.contentType };
+    },
+  });
+}
diff --git a/apps/api/src/routes/tools/index.ts b/apps/api/src/routes/tools/index.ts
index 1cbcc054..18ef1676 100644
--- a/apps/api/src/routes/tools/index.ts
+++ b/apps/api/src/routes/tools/index.ts
@@ -8,6 +8,7 @@ import { registerBorder } from "./border.js";
 import { registerBulkRename } from "./bulk-rename.js";
 import { registerCollage } from "./collage.js";
 import { registerColorAdjustments } from "./color-adjustments.js";
+import { registerColorBlindness } from "./color-blindness.js";
 import { registerColorPalette } from "./color-palette.js";
 import { registerColorize } from "./colorize.js";
 import { registerCompare } from "./compare.js";
@@ -131,6 +132,7 @@ export async function registerToolRoutes(app: FastifyInstance): Promise<void> {
 
     // Adjustments extra
     { id: "replace-color", register: registerReplaceColor },
+    { id: "color-blindness", register: registerColorBlindness },
 
     // AI Tools
     { id: "remove-background", register: registerRemoveBackground },
diff --git a/tests/integration/color-blindness.test.ts b/tests/integration/color-blindness.test.ts
new file mode 100644
index 00000000..33e8231c
--- /dev/null
+++ b/tests/integration/color-blindness.test.ts
@@ -0,0 +1,216 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import sharp from "sharp";
+import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { buildTestApp, createMultipartPayload, loginAsAdmin, type TestApp } from "./test-server.js";
+
+const FIXTURES = join(__dirname, "..", "fixtures");
+const PNG = readFileSync(join(FIXTURES, "test-200x150.png"));
+const JPG = readFileSync(join(FIXTURES, "test-100x100.jpg"));
+
+const ALL_TYPES = [
+  "protanopia",
+  "deuteranopia",
+  "tritanopia",
+  "protanomaly",
+  "deuteranomaly",
+  "tritanomaly",
+  "achromatopsia",
+  "blueConeMonochromacy",
+] as const;
+
+let testApp: TestApp;
+let app: TestApp["app"];
+let adminToken: string;
+
+beforeAll(async () => {
+  testApp = await buildTestApp();
+  app = testApp.app;
+  adminToken = await loginAsAdmin(app);
+}, 30_000);
+
+afterAll(async () => {
+  await testApp.cleanup();
+}, 10_000);
+
+function makePayload(
+  settings: Record<string, unknown>,
+  buffer: Buffer = PNG,
+  filename = "test.png",
+  contentType = "image/png",
+) {
+  return createMultipartPayload([
+    { name: "file", filename, contentType, content: buffer },
+    { name: "settings", content: JSON.stringify(settings) },
+  ]);
+}
+
+async function postTool(
+  settings: Record<string, unknown>,
+  buffer?: Buffer,
+  filename?: string,
+  ct?: string,
+) {
+  const { body: payload, contentType } = makePayload(settings, buffer, filename, ct);
+  return app.inject({
+    method: "POST",
+    url: "/api/v1/tools/color-blindness",
+    payload,
+    headers: {
+      "content-type": contentType,
+      authorization: `Bearer ${adminToken}`,
+    },
+  });
+}
+
+describe("Default settings", () => {
+  it("processes with default settings (deuteranomaly)", async () => {
+    const res = await postTool({});
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+    expect(result.processedSize).toBeGreaterThan(0);
+  });
+});
+
+describe("All 8 simulation types", () => {
+  for (const type of ALL_TYPES) {
+    it(`processes with simulationType=${type}`, async () => {
+      const res = await postTool({ simulationType: type });
+      expect(res.statusCode).toBe(200);
+      const result = JSON.parse(res.body);
+      expect(result.downloadUrl).toBeDefined();
+    });
+  }
+
+  it("different types produce different outputs", async () => {
+    const buffers: Buffer[] = [];
+    for (const type of ["protanopia", "tritanopia", "achromatopsia"] as const) {
+      const res = await postTool({ simulationType: type });
+      expect(res.statusCode).toBe(200);
+      const result = JSON.parse(res.body);
+      const dlRes = await app.inject({
+        method: "GET",
+        url: result.downloadUrl,
+        headers: { authorization: `Bearer ${adminToken}` },
+      });
+      buffers.push(dlRes.rawPayload);
+    }
+    const pixelSets = await Promise.all(
+      buffers.map(async (buf) => {
+        const { data } = await sharp(buf).removeAlpha().raw().toBuffer({ resolveWithObject: true });
+        return `${data[0]},${data[1]},${data[2]}`;
+      }),
+    );
+    const unique = new Set(pixelSets);
+    expect(unique.size).toBeGreaterThan(1);
+  });
+});
+
+describe("Dimension preservation", () => {
+  it("output has same dimensions as input", async () => {
+    const res = await postTool({ simulationType: "protanopia" });
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    const dlRes = await app.inject({
+      method: "GET",
+      url: result.downloadUrl,
+      headers: { authorization: `Bearer ${adminToken}` },
+    });
+    const meta = await sharp(dlRes.rawPayload).metadata();
+    expect(meta.width).toBe(200);
+    expect(meta.height).toBe(150);
+  });
+});
+
+describe("Multiple input formats", () => {
+  it("processes JPEG input", async () => {
+    const res = await postTool({ simulationType: "deuteranopia" }, JPG, "test.jpg", "image/jpeg");
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.downloadUrl).toBeDefined();
+  });
+
+  it("processes WebP input", async () => {
+    const WEBP = readFileSync(join(FIXTURES, "test-50x50.webp"));
+    const res = await postTool({ simulationType: "tritanopia" }, WEBP, "test.webp", "image/webp");
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("processes HEIC input", { timeout: 120_000 }, async () => {
+    const HEIC = readFileSync(join(FIXTURES, "test-200x150.heic"));
+    const res = await postTool({ simulationType: "protanomaly" }, HEIC, "photo.heic", "image/heic");
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("processes SVG input", async () => {
+    const SVG = readFileSync(join(FIXTURES, "test-100x100.svg"));
+    const res = await postTool(
+      { simulationType: "achromatopsia" },
+      SVG,
+      "icon.svg",
+      "image/svg+xml",
+    );
+    expect(res.statusCode).toBe(200);
+  });
+
+  it("processes animated GIF input", async () => {
+    const GIF = readFileSync(join(FIXTURES, "animated.gif"));
+    const res = await postTool({ simulationType: "deuteranomaly" }, GIF, "anim.gif", "image/gif");
+    expect(res.statusCode).toBe(200);
+  });
+});
+
+describe("Error handling", () => {
+  it("returns 400 when no file is provided", async () => {
+    const { body: payload, contentType } = createMultipartPayload([
+      { name: "settings", content: JSON.stringify({ simulationType: "protanopia" }) },
+    ]);
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/color-blindness",
+      payload,
+      headers: {
+        "content-type": contentType,
+        authorization: `Bearer ${adminToken}`,
+      },
+    });
+    expect(res.statusCode).toBe(400);
+  });
+
+  it("returns 400 for invalid simulationType value", async () => {
+    const res = await postTool({ simulationType: "invalid-type" });
+    expect(res.statusCode).toBe(400);
+  });
+});
+
+describe("Edge cases", () => {
+  it("processes 1x1 pixel image", async () => {
+    const TINY = readFileSync(join(FIXTURES, "test-1x1.png"));
+    const res = await postTool({ simulationType: "deuteranomaly" }, TINY, "tiny.png", "image/png");
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.processedSize).toBeGreaterThan(0);
+  });
+
+  it("processes stress-large.jpg", async () => {
+    const LARGE = readFileSync(join(FIXTURES, "content", "stress-large.jpg"));
+    const res = await postTool({ simulationType: "protanopia" }, LARGE, "large.jpg", "image/jpeg");
+    expect(res.statusCode).toBe(200);
+    const result = JSON.parse(res.body);
+    expect(result.processedSize).toBeGreaterThan(0);
+  });
+});
+
+describe("Authentication", () => {
+  it("rejects unauthenticated request", async () => {
+    const { body: payload, contentType } = makePayload({ simulationType: "protanopia" });
+    const res = await app.inject({
+      method: "POST",
+      url: "/api/v1/tools/color-blindness",
+      payload,
+      headers: { "content-type": contentType },
+    });
+    expect(res.statusCode).toBe(401);
+  });
+});