diff --git a/src/helpers/errors.js b/src/helpers/errors.js
index 458d0f9..8b23acc 100644
--- a/src/helpers/errors.js
+++ b/src/helpers/errors.js
@@ -1,19 +1,20 @@
-import typedError from 'error/typed';
+export function WorkerTimeoutError(message, props = {}) {
+  this.name = 'WorkerTimeoutError';
+  this.message = message;
+  this.timeout = props.timeout;
+  this.jobId = props.jobId;
 
-const errors = {};
+  if ("captureStackTrace" in Error) Error.captureStackTrace(this, WorkerTimeoutError);
+  else this.stack = (new Error()).stack;
+}
+WorkerTimeoutError.prototype = Object.create(Error.prototype);
 
-errors.WorkerTimeoutError = typedError({
-  type: 'WorkerTimeoutError',
-  message: 'worker timed out, timeout={timeout}',
-  timeout: null,
-  jobId: null
-});
+export function UnspecifiedWorkerError(message, props = {}) {
+  this.name = 'UnspecifiedWorkerError';
+  this.message = message;
+  this.jobId = props.jobId;
 
-errors.UnspecifiedWorkerError = typedError({
-  type: 'UnspecifiedWorkerError',
-  message: 'Unspecified worker error',
-  timeout: null,
-  jobId: null
-});
-
-export default errors;
+  if ("captureStackTrace" in Error) Error.captureStackTrace(this, UnspecifiedWorkerError);
+  else this.stack = (new Error()).stack;
+}
+UnspecifiedWorkerError.prototype = Object.create(Error.prototype);
diff --git a/test/src/helpers/errors.js b/test/src/helpers/errors.js
new file mode 100644
index 0000000..239a7d7
--- /dev/null
+++ b/test/src/helpers/errors.js
@@ -0,0 +1,51 @@
+import expect from 'expect.js';
+import { WorkerTimeoutError, UnspecifiedWorkerError } from '../../../lib/helpers/errors';
+
+describe('custom errors', function () {
+  describe('WorkerTimeoutError', function () {
+    it('should be function', () => {
+      expect(WorkerTimeoutError).to.be.a('function');
+    });
+
+    it('should have a name', function () {
+      const err = new WorkerTimeoutError('timeout error');
+      expect(err).to.have.property('name', 'WorkerTimeoutError');
+    });
+
+    it('should take a jobId property', function () {
+      const err = new WorkerTimeoutError('timeout error', { jobId: 'il7hl34rqlo8ro' });
+      expect(err).to.have.property('jobId', 'il7hl34rqlo8ro');
+    });
+
+    it('should take a timeout property', function () {
+      const err = new WorkerTimeoutError('timeout error', { timeout: 15000 });
+      expect(err).to.have.property('timeout', 15000);
+    });
+
+    it('should be stringifyable', function () {
+      const err = new WorkerTimeoutError('timeout error');
+      expect(`${err}`).to.equal('WorkerTimeoutError: timeout error');
+    });
+  });
+
+  describe('UnspecifiedWorkerError', function () {
+    it('should be function', () => {
+      expect(UnspecifiedWorkerError).to.be.a('function');
+    });
+
+    it('should have a name', function () {
+      const err = new UnspecifiedWorkerError('unspecified error');
+      expect(err).to.have.property('name', 'UnspecifiedWorkerError');
+    });
+
+    it('should take a jobId property', function () {
+      const err = new UnspecifiedWorkerError('unspecified error', { jobId: 'il7hl34rqlo8ro' });
+      expect(err).to.have.property('jobId', 'il7hl34rqlo8ro');
+    });
+
+    it('should be stringifyable', function () {
+      const err = new UnspecifiedWorkerError('unspecified error');
+      expect(`${err}`).to.equal('UnspecifiedWorkerError: unspecified error');
+    });
+  });
+});