diff --git a/README.md b/README.md
index ca3a352..3b83a04 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ work in progress...
 * ~~YAML project and server(executors count, etc) configs~~
 * ~~Persistent build and console output information~~
 * ~~Project relations (blocks, triggers, etc)~~
-* Writes to stderr must not break the build
+* ~~Writes to stderr must not break the build~~
 * Mail and jabber notifications (with commits, current step and error)
 * ~~Rename notification strategies according to statuses~~
 * Work with git
diff --git a/lib/command/base.js b/lib/command/base.js
index a9431b3..6b7b3e2 100644
--- a/lib/command/base.js
+++ b/lib/command/base.js
@@ -7,6 +7,8 @@ function Command(params) {
 	params = params || {};
 	this.emitIn = params.emitIn;
 	this.emitOut = params.emitOut;
+	this.emitErr = params.emitErr;
+	this.attachStderr = params.attachStderr;
 }
 
 exports.Command = Command;
diff --git a/lib/command/spawn.js b/lib/command/spawn.js
index 24174f1..3ed2c54 100644
--- a/lib/command/spawn.js
+++ b/lib/command/spawn.js
@@ -20,11 +20,11 @@ inherits(Command, ParentCommand);
  */
 Command.prototype.run = function(params, callback) {
 	var self = this,
-		stdout = self.collectOut ? '' : null;
+		stdout = self.collectOut ? '' : null,
+		stderr = self.attachStderr ? '' : null;
 
 	if (!params.cmd) return callback(new Error('`cmd` is not set'));
 	if (!params.args) return callback(new Error('`args` is not set'));
-	callback = _(callback).once();
 	params.options = params.options || {};
 	params.options.cwd = params.options.cwd || this.cwd;
 
@@ -40,15 +40,16 @@ Command.prototype.run = function(params, callback) {
 	});
 
 	cmd.stderr.on('data', function(data) {
-		callback(new Error('Spawned command outputs to stderr: ' + data));
-		cmd.kill();
+		if (self.emitErr) self.emit('stderr', data);
+		if (self.attachStderr) stderr += data;
 	});
 
 	cmd.on('close', function(code) {
 		var err = null;
-		if (code !== 0) err = new Error(
-			'Spawned command exits with non-zero code: ' + code
-		);
+		if (code !== 0) {
+			err = new Error('Spawned command exits with non-zero code: ' + code);
+			err.stderr = stderr;
+		}
 		callback(err, stdout);
 	});
 
diff --git a/lib/distributor.js b/lib/distributor.js
index 2f06096..b796bd8 100644
--- a/lib/distributor.js
+++ b/lib/distributor.js
@@ -74,7 +74,9 @@ Distributor.prototype._runNext = function(callback) {
 						endDate: Date.now(),
 						status: err ? 'error' : 'done',
 						completed: true,
-						error: err ? err.message : null
+						error: err ? {
+							message: err.message, stderr: err.stderr
+						} : null
 					},
 					function(err, build) {
 						if (err) {
diff --git a/lib/executor/local.js b/lib/executor/local.js
index a7de3cd..665079d 100644
--- a/lib/executor/local.js
+++ b/lib/executor/local.js
@@ -92,7 +92,9 @@ Executor.prototype._runStep = function(params, callback) {
 			var command = createCommand(
 				_({
 					emitIn: true,
-					emitOut: true
+					emitOut: true,
+					emitErr: true,
+					attachStderr: true
 				}).extend(params)
 			);
 
@@ -104,6 +106,10 @@ Executor.prototype._runStep = function(params, callback) {
 				self.emit('data', String(data));
 			});
 
+			command.on('stderr', function(data) {
+				self.emit('data', 'stderr: ' + String(data));
+			});
+
 			command.run(params, this.slot())
 		},
 		callback
diff --git a/static/js/app/components/builds/view.jade b/static/js/app/components/builds/view.jade
index edb2128..8c6f8f0 100644
--- a/static/js/app/components/builds/view.jade
+++ b/static/js/app/components/builds/view.jade
@@ -41,7 +41,11 @@ if this.state.build
 	div
 		if this.state.build.error
 			| Error: 
-			span= this.state.build.error
+			span= this.state.build.error.message
+
+		if this.state.build.error.stderr
+			div stderr: 
+			pre= this.state.build.error.stderr
 
 	.row
 		.col-md-8
diff --git a/test/commands/shell.js b/test/commands/shell.js
index 751ccad..49ed5ce 100644
--- a/test/commands/shell.js
+++ b/test/commands/shell.js
@@ -8,7 +8,8 @@ describe('Shell command', function() {
 	var shellCommand;
 	it('Should be created without errors', function() {
 		shellCommand = new ShellCommand({
-			emitOut: true
+			emitOut: true,
+			attachStderr: true
 		});
 	});
 
@@ -40,9 +41,12 @@ describe('Shell command', function() {
 		shellCommand.run({cmd: 'echo1 "Hello world"'}, function(err) {
 			expect(err).ok();
 			expect(err).an(Error);
-			// messages are slightly different across the OSes
+			// messages and codes are slightly different across the OSes
 			// e.g. at linux and macos
-			expect(err.message).match(/echo1:.*not found/);
+			expect(err.message).match(
+				/^Spawned command exits with non-zero code: \d+/
+			);
+			expect(err.stderr).match(/echo1:.*not found/);
 			expect(std.err).equal('');
 			expect(std.out).equal('');
 			done();
diff --git a/test/distributor/main.js b/test/distributor/main.js
index 6ebe22a..69d8e86 100644
--- a/test/distributor/main.js
+++ b/test/distributor/main.js
@@ -15,7 +15,7 @@ describe('Distributor main', function() {
 		expect(distributor.queue).length(conditions.queue.length);
 		expect(build.status).equal(conditions.build.status);
 		if (build.status === 'error') {
-			expect(build.error).eql(conditions.build.error.message);
+			expect(build.error.message).eql(conditions.build.error.message);
 		}
 	};
 
@@ -117,7 +117,7 @@ describe('Distributor main', function() {
 			var changes = updateBuildSpy.getCall(2).args[1];
 			expect(changes.status).equal('error');
 			expect(changes.completed).equal(true);
-			expect(changes.error).equal('Some error');
+			expect(changes.error.message).equal('Some error');
 		});
 
 		it('update build called 3 times in total', function() {