diff --git a/libs/core/di/connection-factory.ts b/libs/core/di/src/connection-factory.ts
similarity index 100%
rename from libs/core/di/connection-factory.ts
rename to libs/core/di/src/connection-factory.ts
diff --git a/libs/core/di/index.ts b/libs/core/di/src/index.ts
similarity index 100%
rename from libs/core/di/index.ts
rename to libs/core/di/src/index.ts
diff --git a/libs/core/di/operation-context.ts b/libs/core/di/src/operation-context.ts
similarity index 100%
rename from libs/core/di/operation-context.ts
rename to libs/core/di/src/operation-context.ts
diff --git a/libs/core/di/pool-size-calculator.ts b/libs/core/di/src/pool-size-calculator.ts
similarity index 100%
rename from libs/core/di/pool-size-calculator.ts
rename to libs/core/di/src/pool-size-calculator.ts
diff --git a/libs/core/di/service-container.ts b/libs/core/di/src/service-container.ts
similarity index 84%
rename from libs/core/di/service-container.ts
rename to libs/core/di/src/service-container.ts
index 562ec2a..d25ac3d 100644
--- a/libs/core/di/service-container.ts
+++ b/libs/core/di/src/service-container.ts
@@ -30,11 +30,38 @@ export class ServiceContainer implements ServiceResolver {
     this.logger.debug('Service registered', { name: registration.name, singleton: registration.singleton });
   }
 
-  resolve<T>(name: string, options?: any): T {
-    const instance = this.resolveAsync<T>(name, options);
+  resolve<T>(name: string, _options?: any): T {
+    // Check scoped instances first
+    if (this.scopedInstances.has(name)) {
+      return this.scopedInstances.get(name);
+    }
+
+    // Check singleton instances
+    if (this.instances.has(name)) {
+      return this.instances.get(name);
+    }
+
+    // Get registration from this container or parent
+    const registration = this.getRegistration(name);
+    if (!registration) {
+      throw new Error(`Service ${name} not registered`);
+    }
+
+    // Create instance synchronously
+    const instance = registration.factory();
+    
+    // Check if factory returned a promise
     if (instance instanceof Promise) {
       throw new Error(`Service ${name} is async. Use resolveAsync() instead.`);
     }
+
+    // Store based on singleton flag
+    if (registration.singleton) {
+      this.instances.set(name, instance);
+    } else {
+      this.scopedInstances.set(name, instance);
+    }
+
     return instance as T;
   }
 
diff --git a/libs/core/di/types.ts b/libs/core/di/src/types.ts
similarity index 100%
rename from libs/core/di/types.ts
rename to libs/core/di/src/types.ts
diff --git a/libs/core/di/test/di.test.ts b/libs/core/di/test/di.test.ts
new file mode 100644
index 0000000..08201ad
--- /dev/null
+++ b/libs/core/di/test/di.test.ts
@@ -0,0 +1,147 @@
+/**
+ * Test DI library functionality
+ */
+import { test, expect, describe } from 'bun:test';
+import { ServiceContainer, ConnectionFactory, OperationContext, PoolSizeCalculator } from '../src/index';
+
+describe('DI Library', () => {
+  test('ServiceContainer - sync resolution', () => {
+    const container = new ServiceContainer('test');
+    
+    container.register({
+      name: 'testService',
+      factory: () => ({ value: 'test' }),
+      singleton: true,
+    });
+
+    const service = container.resolve<{ value: string }>('testService');
+    expect(service.value).toBe('test');
+  });
+
+  test('ServiceContainer - async resolution', async () => {
+    const container = new ServiceContainer('test');
+    
+    container.register({
+      name: 'asyncService',
+      factory: async () => ({ value: 'async-test' }),
+      singleton: true,
+    });
+
+    const service = await container.resolveAsync<{ value: string }>('asyncService');
+    expect(service.value).toBe('async-test');
+  });
+
+  test('ServiceContainer - scoped container', () => {
+    const container = new ServiceContainer('test');
+    
+    container.register({
+      name: 'testService',
+      factory: () => ({ value: 'test' }),
+      singleton: true,
+    });
+
+    const scopedContainer = container.createScope();
+    const service = scopedContainer.resolve<{ value: string }>('testService');
+    expect(service.value).toBe('test');
+  });
+
+  test('ServiceContainer - error on unregistered service', () => {
+    const container = new ServiceContainer('test');
+    
+    expect(() => {
+      container.resolve('nonexistent');
+    }).toThrow('Service nonexistent not registered');
+  });
+
+  test('ServiceContainer - async service throws error on sync resolve', () => {
+    const container = new ServiceContainer('test');
+    
+    container.register({
+      name: 'asyncService',
+      factory: async () => ({ value: 'async' }),
+      singleton: true,
+    });
+
+    expect(() => {
+      container.resolve('asyncService');
+    }).toThrow('Service asyncService is async. Use resolveAsync() instead.');
+  });
+
+  test('ServiceContainer - disposal', async () => {
+    const container = new ServiceContainer('test');
+    let disposed = false;
+    
+    container.register({
+      name: 'disposableService',
+      factory: () => ({ value: 'test' }),
+      singleton: true,
+      dispose: async () => {
+        disposed = true;
+      },
+    });
+
+    // Create instance
+    container.resolve('disposableService');
+    
+    // Dispose container
+    await container.dispose();
+    expect(disposed).toBe(true);
+  });
+
+  test('ConnectionFactory - creation', () => {
+    const factory = new ConnectionFactory({
+      service: 'test',
+      environment: 'development',
+    });
+
+    expect(factory).toBeDefined();
+    expect(factory.listPools()).toEqual([]);
+  });
+
+  test('OperationContext - creation', () => {
+    const container = new ServiceContainer('test');
+    const context = OperationContext.create('test-handler', 'test-operation', {
+      container,
+    });
+
+    expect(context).toBeDefined();
+    expect(context.logger).toBeDefined();
+  });
+
+  test('OperationContext - child context', () => {
+    const context = OperationContext.create('test-handler', 'test-operation');
+    const child = context.createChild('child-operation');
+
+    expect(child).toBeDefined();
+    expect(child.logger).toBeDefined();
+  });
+
+  test('PoolSizeCalculator - service defaults', () => {
+    const poolSize = PoolSizeCalculator.calculate('data-ingestion');
+    expect(poolSize).toEqual({ min: 5, max: 50, idle: 10 });
+  });
+
+  test('PoolSizeCalculator - handler defaults', () => {
+    const poolSize = PoolSizeCalculator.calculate('unknown-service', 'batch-import');
+    expect(poolSize).toEqual({ min: 10, max: 100, idle: 20 });
+  });
+
+  test('PoolSizeCalculator - fallback defaults', () => {
+    const poolSize = PoolSizeCalculator.calculate('unknown-service', 'unknown-handler');
+    expect(poolSize).toEqual({ min: 2, max: 10, idle: 3 });
+  });
+
+  test('PoolSizeCalculator - custom config', () => {
+    const poolSize = PoolSizeCalculator.calculate('test-service', undefined, {
+      minConnections: 5,
+      maxConnections: 15,
+    });
+    expect(poolSize).toEqual({ min: 5, max: 15, idle: 5 });
+  });
+
+  test('PoolSizeCalculator - optimal size calculation', () => {
+    const optimalSize = PoolSizeCalculator.getOptimalPoolSize(10, 100, 50);
+    expect(optimalSize).toBeGreaterThan(0);
+    expect(typeof optimalSize).toBe('number');
+  });
+});
\ No newline at end of file
diff --git a/libs/core/di/tsconfig.json b/libs/core/di/tsconfig.json
index 8a56d2d..b1b5979 100644
--- a/libs/core/di/tsconfig.json
+++ b/libs/core/di/tsconfig.json
@@ -1,15 +1,15 @@
 {
   "extends": "../../../tsconfig.json",
   "compilerOptions": {
-    "rootDir": "./",
+    "rootDir": "./src",
     "outDir": "./dist",
     "composite": true,
     "declaration": true,
     "declarationMap": true,
     "types": ["node", "bun-types"]
   },
-  "include": ["./**/*.ts"],
-  "exclude": ["node_modules", "dist"],
+  "include": ["src/**/*.ts"],
+  "exclude": ["node_modules", "dist", "test"],
   "references": [
     { "path": "../config" },
     { "path": "../logger" }
diff --git a/libs/utils/package.json b/libs/utils/package.json
index 8539074..6412a4f 100644
--- a/libs/utils/package.json
+++ b/libs/utils/package.json
@@ -13,19 +13,8 @@
     "@stock-bot/config": "workspace:*",
     "@stock-bot/logger": "workspace:*",
     "@stock-bot/cache": "workspace:*",
-    "@stock-bot/postgres": "workspace:*",
-    "@stock-bot/mongodb": "workspace:*",
-    "@stock-bot/di": "workspace:*",
     "@stock-bot/types": "workspace:*",
-    "@stock-bot/http": "workspace:*",
-    "cheerio": "^1.0.0",
-    "axios": "^1.7.7",
-    "axios-rate-limit": "^1.4.0",
-    "axios-retry": "^4.4.1",
-    "socks-proxy-agent": "^8.0.2",
-    "p-limit": "^6.1.0",
-    "zod": "^3.22.4",
-    "date-fns": "^2.30.0"
+    "@stock-bot/http": "workspace:*"
   },
   "devDependencies": {
     "@types/node": "^20.11.0",
diff --git a/libs/utils/tsconfig.json b/libs/utils/tsconfig.json
index 380c1f4..d88dafd 100644
--- a/libs/utils/tsconfig.json
+++ b/libs/utils/tsconfig.json
@@ -14,9 +14,6 @@
     { "path": "../data/cache" },
     { "path": "../core/config" },
     { "path": "../core/logger" },
-    { "path": "../services/http" },
-    { "path": "../core/di" },
-    { "path": "../data/mongodb" },
-    { "path": "../data/postgres" }
+    { "path": "../services/http" }
   ]
 }