diff --git a/src/__tests__/fixtures/query.ts b/src/__tests__/fixtures/query.ts
new file mode 100644
index 0000000..49d27c0
--- /dev/null
+++ b/src/__tests__/fixtures/query.ts
@@ -0,0 +1,20 @@
+import * as grpc from "@grpc/grpc-js";
+import type {
+  DataQueryServiceClient,
+  QueryRequest,
+  QueryResponse,
+} from "../../gen/data/v1/data";
+
+export function queryData(
+  client: DataQueryServiceClient,
+  request: QueryRequest,
+  metadata: grpc.Metadata
+): Promise<QueryResponse> {
+  return new Promise((resolve, reject) => {
+    client.query(request, metadata, (error, res) => {
+      if (error) reject(error);
+      else if (!res) reject(new Error("empty response"));
+      else resolve(res);
+    });
+  });
+}
diff --git a/src/__tests__/query.test.ts b/src/__tests__/query.test.ts
new file mode 100644
index 0000000..f84b2ca
--- /dev/null
+++ b/src/__tests__/query.test.ts
@@ -0,0 +1,247 @@
+import { describe, beforeAll, afterAll, it, expect } from "vitest";
+import { DataQueryServiceClient, OrderBy } from "../gen/data/v1/data";
+import {
+  GRPC_ADDRESS,
+  grpcInsecureCredentials,
+  grpcMetadata,
+} from "./fixtures/grpc";
+import { createTestApiKey } from "./fixtures/apiKey";
+import { clearDatabase } from "./db";
+import { queryData } from "./fixtures/query";
+import { getPostgresDB } from "../storage/db/postgres/db";
+import { tagsTable } from "../storage/db/postgres/schema";
+import { FilterCondition, FilterGroup } from "../gen/query/v1/query";
+import { Metadata } from "@grpc/grpc-js";
+
+describe("Data Query", () => {
+  let client: DataQueryServiceClient;
+  let rawKey: string;
+
+  beforeAll(async () => {
+    client = new DataQueryServiceClient(GRPC_ADDRESS, grpcInsecureCredentials);
+    const key = await createTestApiKey();
+    rawKey = key.rawKey;
+  });
+
+  afterAll(async () => {
+    await clearDatabase();
+    client.close();
+  });
+
+  it("1. returns data when auth is valid and table exists", async () => {
+    const db = getPostgresDB();
+    await db.insert(tagsTable).values({
+      key: "PREMIUM_CALL",
+      amount: 100,
+    });
+
+    const QueryRequest = {
+      table: "tags",
+      where: FilterGroup.create({
+        logical: 1,
+        conditions: [
+          FilterCondition.create({
+            field: "key",
+            operator: 1,
+            value: "PREMIUM_CALL",
+          }),
+        ],
+        groups: [],
+      }),
+      orderBy: [],
+      limit: 100,
+      offset: 0,
+    };
+
+    const response = await queryData(
+      client,
+      QueryRequest,
+      grpcMetadata(`Bearer ${rawKey}`)
+    );
+
+    expect(response.columns).toContain("key");
+    expect(response.columns).toContain("amount");
+    expect(response.total).toBe(1);
+    expect(response.rows.length).toBe(1);
+    // expect(response.rows).toBeDefined();
+    expect(response.rows[0]?.values).toBeDefined();
+    expect(response.rows[0]?.values).toContain("PREMIUM_CALL");
+    expect(response.rows[0]?.values).toContain("100");
+  });
+
+  it("2. returns error when table does not exist", async () => {
+    const QueryRequest = {
+      table: "nonexistent",
+      where: FilterGroup.create({
+        logical: 1,
+        conditions: [],
+        groups: [],
+      }),
+      orderBy: [],
+      limit: 100,
+      offset: 0,
+    };
+
+    await expect(
+      queryData(client, QueryRequest, grpcMetadata(`Bearer ${rawKey}`))
+    ).rejects.toThrow(
+      'table: Invalid option: expected one of "users"|"sessions"|"tags"|"expressions"|"metadata"'
+    );
+  });
+
+  it("3. rejects requests without auth", async () => {
+    const QueryRequest = {
+      table: "users",
+      where: FilterGroup.create({
+        logical: 1,
+        conditions: [],
+        groups: [],
+      }),
+      orderBy: [],
+      limit: 100,
+      offset: 0,
+    };
+
+    await expect(
+      queryData(client, QueryRequest, new Metadata())
+    ).rejects.toThrow("Missing Authorization header");
+  });
+
+  it("4. returns 0 results when no rows match the filter", async () => {
+    const db = getPostgresDB();
+    await db.insert(tagsTable).values({ key: "CHEAP", amount: 200 });
+
+    const request = {
+      table: "tags",
+      where: FilterGroup.create({
+        logical: 1,
+        conditions: [
+          FilterCondition.create({
+            field: "amount",
+            operator: 1,
+            value: "696",
+          }),
+        ],
+        groups: [],
+      }),
+      orderBy: [],
+      limit: 100,
+      offset: 0,
+    };
+
+    const response = await queryData(
+      client,
+      request,
+      grpcMetadata(`Bearer ${rawKey}`)
+    );
+
+    expect(response.total).toBe(0);
+    expect(response.rows.length).toBe(0);
+  });
+
+  it("5. returns all rows when no filter is provided", async () => {
+    const db = getPostgresDB();
+    await db.insert(tagsTable).values({ key: "A", amount: 1 });
+    await db.insert(tagsTable).values({ key: "B", amount: 2 });
+    await db.insert(tagsTable).values({ key: "C", amount: 3 });
+
+    const request = {
+      table: "tags",
+      where: FilterGroup.create({
+        logical: 1,
+        conditions: [],
+        groups: [],
+      }),
+      orderBy: [],
+      limit: 100,
+      offset: 0,
+    };
+
+    const response = await queryData(
+      client,
+      request,
+      grpcMetadata(`Bearer ${rawKey}`)
+    );
+
+    expect(response.total).toBeGreaterThanOrEqual(3);
+    expect(response.rows.length).toBeGreaterThanOrEqual(3);
+    expect(response.columns).toContain("key");
+    expect(response.columns).toContain("amount");
+  });
+
+  it("6. supports pagination with limit and offset", async () => {
+    const db = getPostgresDB();
+    await db.insert(tagsTable).values({ key: "P1", amount: 10 });
+    await db.insert(tagsTable).values({ key: "P2", amount: 20 });
+    await db.insert(tagsTable).values({ key: "P3", amount: 30 });
+    await db.insert(tagsTable).values({ key: "P4", amount: 40 });
+    await db.insert(tagsTable).values({ key: "P5", amount: 50 });
+
+    const page1 = await queryData(
+      client,
+      {
+        table: "tags",
+        where: FilterGroup.create({ logical: 1, conditions: [], groups: [] }),
+        orderBy: [],
+        limit: 2,
+        offset: 0,
+      },
+      grpcMetadata(`Bearer ${rawKey}`)
+    );
+
+    expect(page1.total).toBeGreaterThanOrEqual(5);
+    expect(page1.rows.length).toBe(2);
+
+    const page2 = await queryData(
+      client,
+      {
+        table: "tags",
+        where: FilterGroup.create({ logical: 1, conditions: [], groups: [] }),
+        orderBy: [],
+        limit: 2,
+        offset: 2,
+      },
+      grpcMetadata(`Bearer ${rawKey}`)
+    );
+
+    expect(page2.rows.length).toBe(2);
+
+    const page3 = await queryData(
+      client,
+      {
+        table: "tags",
+        where: FilterGroup.create({ logical: 1, conditions: [], groups: [] }),
+        orderBy: [],
+        limit: 2,
+        offset: 4,
+      },
+      grpcMetadata(`Bearer ${rawKey}`)
+    );
+
+    expect(page3.rows.length).toBeGreaterThanOrEqual(1);
+  });
+
+  it("7. rejects invalid integer value in filter", async () => {
+    const request = {
+      table: "tags",
+      where: FilterGroup.create({
+        logical: 1,
+        conditions: [
+          FilterCondition.create({
+            field: "amount",
+            operator: 1,
+            value: "abc",
+          }),
+        ],
+        groups: [],
+      }),
+      orderBy: [],
+      limit: 100,
+      offset: 0,
+    };
+
+    await expect(
+      queryData(client, request, grpcMetadata(`Bearer ${rawKey}`))
+    ).rejects.toThrow();
+  });
+});