diff --git a/infra/gcb/build.py b/infra/gcb/build.py
index e6523cc61..51afc0581 100755
--- a/infra/gcb/build.py
+++ b/infra/gcb/build.py
@@ -6,6 +6,7 @@ Usage: build.py <project_dir>
 """
 
 import base64
+import collections
 import datetime
 import os
 import subprocess
@@ -18,15 +19,28 @@ from oauth2client.client import GoogleCredentials
 from oauth2client.service_account import ServiceAccountCredentials
 from googleapiclient.discovery import build
 
-
 CONFIGURATIONS = {
   'sanitizer-address' : [ 'SANITIZER=address' ],
   'sanitizer-memory' : [ 'SANITIZER=memory' ],
   'sanitizer-undefined' : [ 'SANITIZER=undefined' ],
-  }
+  'engine-libfuzzer' : [ 'FUZZING_ENGINE=libfuzzer' ],
+  'engine-afl' : [ 'FUZZING_ENGINE=afl' ],
+}
 
+EngineInfo = collections.namedtuple(
+    'EngineInfo', ['upload_bucket', 'supported_sanitizers'])
+
+ENGINE_INFO = {
+    'libfuzzer': EngineInfo(
+        upload_bucket='clusterfuzz-builds-test',
+        supported_sanitizers=['address', 'memory', 'undefined']),
+    'afl': EngineInfo(
+        upload_bucket='clusterfuzz-builds-afl-test',
+        supported_sanitizers=['address']),
+}
+
+DEFAULT_ENGINES = ['libfuzzer', 'afl']
 DEFAULT_SANITIZERS = ['address', 'undefined']
-UPLOAD_BUCKET = 'clusterfuzz-builds-test'
 
 
 def usage():
@@ -44,6 +58,7 @@ def load_project_yaml(project_dir):
     project_yaml.setdefault('image',
         'gcr.io/clusterfuzz-external/oss-fuzz/' + project_name)
     project_yaml.setdefault('sanitizers', DEFAULT_SANITIZERS)
+    project_yaml.setdefault('fuzzing_engines', DEFAULT_ENGINES)
     return project_yaml
 
 
@@ -66,6 +81,10 @@ def get_signed_url(path):
           urllib.urlencode(values))
 
 
+def is_supported_configuration(fuzzing_engine, sanitizer):
+  return sanitizer in ENGINE_INFO[fuzzing_engine].supported_sanitizers
+
+
 def get_build_steps(project_yaml):
   name = project_yaml['name']
   image = project_yaml['image']
@@ -94,60 +113,66 @@ def get_build_steps(project_yaml):
           },
     ]
 
-  for sanitizer in project_yaml['sanitizers']:
-    env = CONFIGURATIONS["sanitizer-" + sanitizer][:]
-    out = '/workspace/out/' + sanitizer
-    stamped_name = name + '-' + sanitizer + '-' + ts
-    zip_file = stamped_name + '.zip'
-    stamped_srcmap_file = stamped_name + '.srcmap.json'
-    upload_url = get_signed_url('/{0}/{1}/{2}'.format(
-        UPLOAD_BUCKET, name, zip_file))
-    srcmap_url = get_signed_url('/{0}/{1}/{2}'.format(
-        UPLOAD_BUCKET, name, stamped_srcmap_file))
+  for fuzzing_engine in project_yaml['fuzzing_engines']:
+    for sanitizer in project_yaml['sanitizers']:
+      if not is_supported_configuration(fuzzing_engine, sanitizer):
+        continue
 
-    env.append('OUT=' + out)
+      env = CONFIGURATIONS['engine-' + fuzzing_engine][:]
+      env.extend(CONFIGURATIONS['sanitizer-' + sanitizer])
+      out = '/workspace/out/' + sanitizer
+      stamped_name = name + '-' + sanitizer + '-' + ts
+      zip_file = stamped_name + '.zip'
+      stamped_srcmap_file = stamped_name + '.srcmap.json'
+      bucket = ENGINE_INFO[fuzzing_engine].upload_bucket
+      upload_url = get_signed_url('/{0}/{1}/{2}'.format(
+          bucket, name, zip_file))
+      srcmap_url = get_signed_url('/{0}/{1}/{2}'.format(
+          bucket, name, stamped_srcmap_file))
 
-    build_steps.extend([
-        # compile
-        {'name': image,
-          'env' : env,
-          'args': [
-            'bash',
-            '-c',
-            'cd /src/{1} && mkdir -p {0} && compile'.format(out, name),
+      env.append('OUT=' + out)
+
+      build_steps.extend([
+          # compile
+          {'name': image,
+            'env' : env,
+            'args': [
+              'bash',
+              '-c',
+              'cd /src/{1} && mkdir -p {0} && compile'.format(out, name),
+              ],
+            },
+          # zip binaries
+          {'name': image,
+            'args': [
+              'bash',
+              '-c',
+              'cd {0} && zip -r {1} *'.format(out, zip_file)
             ],
           },
-        # zip binaries
-        {'name': image,
-          'args': [
-            'bash',
-            '-c',
-            'cd {0} && zip -r {1} *'.format(out, zip_file)
-          ],
-        },
-        # upload binaries
-        {'name': 'gcr.io/clusterfuzz-external/uploader',
-         'args': [
-             os.path.join(out, zip_file),
-             upload_url,
-         ],
-        },
-        # upload srcmap
-        {'name': 'gcr.io/clusterfuzz-external/uploader',
-         'args': [
-             '/workspace/srcmap.json',
-             srcmap_url,
-         ],
-        },
-        # cleanup
-        {'name': image,
-          'args': [
-            'bash',
-            '-c',
-            'rm -r ' + out,
-          ],
-        },
-    ])
+          # upload binaries
+          {'name': 'gcr.io/clusterfuzz-external/uploader',
+           'args': [
+               os.path.join(out, zip_file),
+               upload_url,
+           ],
+          },
+          # upload srcmap
+          {'name': 'gcr.io/clusterfuzz-external/uploader',
+           'args': [
+               '/workspace/srcmap.json',
+               srcmap_url,
+           ],
+          },
+          # cleanup
+          {'name': image,
+            'args': [
+              'bash',
+              '-c',
+              'rm -r ' + out,
+            ],
+          },
+      ])
 
   return build_steps