diff --git a/src/config.ts b/src/config.ts
index f136a9c..f5e4215 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -21,14 +21,21 @@ const InputConfigSchema = z.object({
   outputImages: z.array(OutputImageConfigSchema).min(1),
 });
 
+const CredentialsSchema = z.object({
+  accessKeyId: z.string(),
+  secretKey: z.string(),
+  endpointUrl: z.string(),
+});
+
 const ConfigSchema = z.object({
   bucketName: z.string(),
   inputConfig: InputConfigSchema,
+  credentials: CredentialsSchema.optional(),
 });
 
 export type Config = z.infer<typeof ConfigSchema>;
 
-const validateConfig = (config: unknown): Config => {
+export const validateConfig = (config: unknown): Config => {
   const configObj = ConfigSchema.parse(config);
   const { inputConfig } = configObj;
 
@@ -51,6 +58,28 @@ const validateConfig = (config: unknown): Config => {
   return configObj;
 };
 
+export const getCredentials = (configCredentials?: {
+  accessKeyId?: string;
+  secretKey?: string;
+  endpointUrl?: string;
+}) => {
+  const envCredentials = {
+    accessKeyId: process.env.ACCESS_KEY_ID,
+    secretKey: process.env.SECRET_KEY,
+    endpointUrl: process.env.ENDPOINT_URL,
+  };
+
+  const finalCredentials = {
+    accessKeyId: configCredentials?.accessKeyId || envCredentials.accessKeyId,
+    secretKey: configCredentials?.secretKey || envCredentials.secretKey,
+    endpointUrl: configCredentials?.endpointUrl || envCredentials.endpointUrl,
+  };
+
+  const parsedCredentials = CredentialsSchema.parse(finalCredentials);
+
+  return parsedCredentials;
+};
+
 export const getConfig = (): Config => {
   try {
     const explorerSync = cosmiconfigSync("lilsync");
@@ -60,7 +89,10 @@ export const getConfig = (): Config => {
       throw new Error("configuration file not found or is empty");
     }
 
-    return validateConfig(result.config);
+    const config = validateConfig(result.config);
+    config.credentials = getCredentials(result.config.credentials);
+
+    return config;
   } catch (err) {
     if (err instanceof z.ZodError) {
       const formattedErrors = err.errors
diff --git a/src/test/config.test.ts b/src/test/config.test.ts
new file mode 100644
index 0000000..0ac05b7
--- /dev/null
+++ b/src/test/config.test.ts
@@ -0,0 +1,181 @@
+import { cosmiconfigSync } from "cosmiconfig";
+
+import { getConfig, validateConfig, getCredentials } from "../config";
+
+jest.mock("cosmiconfig");
+jest.mock("dotenv");
+
+describe("Config Tests", () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe("validateConfig", () => {
+    const validConfig = {
+      bucketName: "test-bucket",
+      inputConfig: {
+        outputPath: "/output/path",
+        inputPath: "/input/path",
+        outputImages: [{ width: 1000, height: 2000, ext: "png", quality: 90 }],
+      },
+    };
+
+    const invalidConfigs = [
+      {
+        case: "missing bucketName",
+        config: {
+          inputConfig: {
+            outputPath: "/output/path",
+            inputPath: "/input/path",
+            outputImages: [
+              { width: 1000, height: 2000, ext: "png", quality: 90 },
+            ],
+          },
+        },
+      },
+      {
+        case: "duplicate dimensions",
+        config: {
+          bucketName: "test-bucket",
+          inputConfig: {
+            outputPath: "/output/path",
+            inputPath: "/input/path",
+            outputImages: [
+              { width: 1000, height: 2000, ext: "png", quality: 90 },
+              { width: 1000, height: 3000, ext: "jpg", quality: 80 },
+            ],
+          },
+        },
+      },
+    ];
+
+    test("should validate a valid config", () => {
+      expect(() => validateConfig(validConfig)).not.toThrow();
+    });
+
+    test.each(invalidConfigs)("should throw error for $case", ({ config }) => {
+      expect(() => validateConfig(config)).toThrow(Error);
+    });
+  });
+
+  describe("getCredentials", () => {
+    const envCredentials = {
+      ACCESS_KEY_ID: "env-access-key-id",
+      SECRET_KEY: "env-secret-key",
+      ENDPOINT_URL: "env-endpoint-url",
+    };
+
+    const configCredentials = {
+      accessKeyId: "config-access-key-id",
+      secretKey: "config-secret-key",
+      endpointUrl: "config-endpoint-url",
+    };
+
+    const testCases = [
+      {
+        description:
+          "if both config and env credentials are provided, use config credentials",
+        env: envCredentials,
+        config: configCredentials,
+        expected: configCredentials,
+      },
+      {
+        description:
+          "if only env credentials are provided, use env credentials",
+        env: envCredentials,
+        config: {},
+        expected: {
+          accessKeyId: "env-access-key-id",
+          secretKey: "env-secret-key",
+          endpointUrl: "env-endpoint-url",
+        },
+      },
+      {
+        description:
+          "if only config credentials are provided, use config credentials",
+        env: {},
+        config: configCredentials,
+        expected: configCredentials,
+      },
+    ];
+
+    test.each(testCases)(
+      "should return correct credentials $description",
+      ({ env, config, expected }) => {
+        process.env = { ...env };
+        const result = getCredentials(config);
+        expect(result).toEqual(expected);
+      }
+    );
+  });
+
+  describe("getConfig", () => {
+    const validConfig = {
+      config: {
+        bucketName: "test-bucket",
+        inputConfig: {
+          outputPath: "/output/path",
+          inputPath: "/input/path",
+          outputImages: [
+            { width: 1000, height: 2000, ext: "png", quality: 90 },
+          ],
+        },
+        credentials: {
+          accessKeyId: "config-access-key-id",
+          secretKey: "config-secret-key",
+          endpointUrl: "config-endpoint-url",
+        },
+      },
+    };
+
+    const cosmiconfigMock = cosmiconfigSync as jest.Mock;
+
+    test("should return parsed config if everything is valid", () => {
+      cosmiconfigMock.mockReturnValue({
+        search: jest.fn().mockReturnValue(validConfig),
+      });
+
+      const result = getConfig();
+      expect(result).toEqual({
+        ...validConfig.config,
+      });
+    });
+
+    test("should throw error if config file is not found or empty", () => {
+      cosmiconfigMock.mockReturnValue({
+        search: jest.fn().mockReturnValue(null),
+      });
+
+      expect(() => getConfig()).toThrow(
+        "configuration file not found or is empty"
+      );
+    });
+
+    test("should throw validation error with formatted message", () => {
+      const invalidConfig = {
+        config: {
+          bucketName: 12345, // Invalid type
+          inputConfig: {
+            outputPath: "/output/path",
+            inputPath: "/input/path",
+            outputImages: [
+              { width: 1000, height: 2000, ext: "png", quality: 101 }, // Invalid quality
+            ],
+          },
+        },
+      };
+
+      cosmiconfigMock.mockReturnValue({
+        search: jest.fn().mockReturnValue(invalidConfig),
+      });
+
+      try {
+        getConfig();
+      } catch (error) {
+        if (error instanceof Error) {
+          expect(error.message).toContain("Configuration validation error:");
+        }
+      }
+    });
+  });
+});