diff --git a/src/tools/vppapitrace/vppapitrace.py b/src/tools/vppapitrace/vppapitrace.py
new file mode 100755
index 0000000..df07580
--- /dev/null
+++ b/src/tools/vppapitrace/vppapitrace.py
@@ -0,0 +1,434 @@
+#!/usr/bin/env python3
+
+#
+# Copyright (c) 2019 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+#
+# Convert from VPP API trace to JSON.
+
+import argparse
+import struct
+import sys
+import logging
+import json
+from ipaddress import *
+from collections import namedtuple
+from vpp_papi import MACAddress, VPPApiJSONFiles
+import base64
+import os
+
+
+def serialize_likely_small_unsigned_integer(x):
+    r = x
+
+    # Low bit set means it fits into 1 byte.
+    if r < (1 << 7):
+        return struct.pack("B", 1 + 2 * r)
+
+    # Low 2 bits 1 0 means it fits into 2 bytes.
+    r -= (1 << 7)
+    if r < (1 << 14):
+        return struct.pack("<H", 4 * r + 2)
+
+    r -= (1 << 14)
+    if r < (1 << 29):
+        return struct.pack("<I", 8 * r + 4)
+
+    return struct.pack("<BQ", 0, x)
+
+
+def unserialize_likely_small_unsigned_integer(data, offset):
+    y = struct.unpack_from("B", data, offset)[0]
+    if y & 1:
+        return y // 2, 1
+    r = 1 << 7
+    if y & 2:
+        p = struct.unpack_from("B", data, offset + 1)[0]
+        r += (y // 4) + (p << 6)
+        return r, 2
+    r += 1 << 14
+    if y & 4:
+        (p1, p2, p3) = struct.unpack_from("BBB", data, offset+1)
+        r += ((y // 8) + (p1 << (5 + 8 * 0))
+              + (p2 << (5 + 8 * 1)) + (p3 << (5 + 8 * 2)))
+        return r, 3
+    return struct.unpack_from(">Q", data, offset+1)[0], 8
+
+
+def serialize_cstring(s):
+    bstring = s.encode('utf8')
+    l = len(bstring)
+    b = serialize_likely_small_unsigned_integer(l))
+    b += struct.pack('{}s'.format(l), bstring)
+    return b
+
+
+def unserialize_cstring(data, offset):
+    l, size = unserialize_likely_small_unsigned_integer(data, offset)
+    name = struct.unpack_from('{}s'.format(l), data, offset+size)[0]
+    return name.decode('utf8'), size + len(name)
+
+
+def unserialize_msgtbl(data, offset):
+    msgtable_by_id = {}
+    msgtable_by_name = {}
+    i = 0
+    nmsg = struct.unpack_from(">I", data, offset)[0]
+    o = 4
+    while i < nmsg:
+        (msgid, size) = unserialize_likely_small_unsigned_integer(
+            data, offset + o)
+        o += size
+        (name, size) = unserialize_cstring(data, offset + o)
+        o += size
+        msgtable_by_id[msgid] = name
+        msgtable_by_name[name] = msgid
+
+        i += 1
+    return msgtable_by_id, msgtable_by_name, o
+
+
+def serialize_msgtbl(messages):
+    offset = 0
+    data = bytearray(100000)
+    nmsg = len(messages)
+    data = struct.pack(">I", nmsg)
+
+    for k, v in messages.items():
+        name = k + '_' + v.crc[2:]
+        data += serialize_likely_small_unsigned_integer(v._vl_msg_id)
+        data += serialize_cstring(name)
+    return data
+
+
+def apitrace2json(messages, filename):
+    result = []
+    with open(filename, 'rb') as file:
+        bytes_read = file.read()
+        # Read header
+        (nitems, msgtbl_size, wrapped) = struct.unpack_from(">IIB",
+                                                            bytes_read, 0)
+        logging.debug('nitems: {} message table size: {} wrapped: {}'
+                      .format(nitems, msgtbl_size, wrapped))
+        if wrapped:
+            sys.stdout.write('Wrapped/incomplete trace, results may vary')
+        offset = 9
+
+        msgtbl_by_id, msgtbl_by_name, size = unserialize_msgtbl(bytes_read,
+                                                                offset)
+        offset += size
+
+        i = 0
+        while i < nitems:
+            size = struct.unpack_from(">I", bytes_read, offset)[0]
+            offset += 4
+            if size == 0:
+                break
+            msgid = struct.unpack_from(">H", bytes_read, offset)[0]
+            name = msgtbl_by_id[msgid]
+            n = name[:name.rfind("_")]
+            msgobj = messages[n]
+            if n + '_' + msgobj.crc[2:] != name:
+                sys.exit("CRC Mismatch between JSON API definition "
+                         "and trace. {}".format(name))
+
+            x, s = msgobj.unpack(bytes_read[offset:offset+size])
+            msgname = type(x).__name__
+            offset += size
+            # Replace named tuple illegal _0
+            y = x._asdict()
+            y.pop('_0')
+            result.append({'name': msgname, 'args': y})
+            i += 1
+
+    file.close()
+    return result
+
+
+def json2apitrace(messages, filename):
+    """Input JSON file and API message definition. Output API trace
+    bytestring."""
+
+    msgs = []
+    with open(filename, 'r') as file:
+        msgs = json.load(file, object_hook=vpp_decode)
+    result = b''
+    for m in msgs:
+        name = m['name']
+        msgobj = messages[name]
+        m['args']['_vl_msg_id'] = messages[name]._vl_msg_id
+        b = msgobj.pack(m['args'])
+
+        result += struct.pack('>I', len(b))
+        result += b
+    return len(msgs), result
+
+
+class VPPEncoder(json.JSONEncoder):
+    def default(self, o):
+        if type(o) is bytes:
+            return "base64:" + base64.b64encode(o).decode('utf-8')
+        # Let the base class default method raise the TypeError
+        return json.JSONEncoder.default(self, o)
+
+    def encode(self, obj):
+        def hint_tuples(item):
+            if isinstance(item, tuple):
+                return hint_tuples(item._asdict())
+            if isinstance(item, list):
+                return [hint_tuples(e) for e in item]
+            if isinstance(item, dict):
+                return {key: hint_tuples(value) for key, value in item.items()}
+            else:
+                return item
+
+        return super(VPPEncoder, self).encode(hint_tuples(obj))
+
+
+def vpp_decode(obj):
+    for k, v in obj.items():
+        if type(v) is str and v.startswith('base64:'):
+            s = v.lstrip('base64:')
+            obj[k] = base64.b64decode(v[7:])
+    return obj
+
+
+def vpp_encoder(obj):
+    if isinstance(obj, IPv6Network):
+        return str(obj)
+    if isinstance(obj, IPv4Network):
+        return str(obj)
+    if isinstance(obj, IPv6Address):
+        return str(obj)
+    if isinstance(obj, IPv4Address):
+        return str(obj)
+    if isinstance(obj, MACAddress):
+        return str(obj)
+    if type(obj) is bytes:
+        return "base64:" + base64.b64encode(obj).decode('ascii')
+    raise TypeError('Unknown object {} {}\n'.format(type(obj), obj))
+
+message_filter = {
+    'control_ping',
+    'memclnt_create',
+    'memclnt_delete',
+    'get_first_msg_id',
+}
+
+argument_filter = {
+    'client_index',
+    'context',
+}
+
+def topython(messages, services):
+    import pprint
+    pp = pprint.PrettyPrinter()
+
+    s = '''\
+#!/usr/bin/env python3
+from vpp_papi import VPP, VppEnum
+vpp = VPP(use_socket=True)
+vpp.connect(name='vppapitrace')
+'''
+
+    for m in messages:
+        if m['name'] not in services:
+            s += '# ignoring reply message: {}\n'.format(m['name'])
+            continue
+        if m['name'] in message_filter:
+            s += '# ignoring message {}\n'.format(m['name'])
+            continue
+        for k in argument_filter:
+            try:
+                m['args'].pop(k)
+            except KeyError:
+                pass
+        a = pp.pformat(m['args'])
+        s += 'rv = vpp.api.{}(**{})\n'.format(m['name'], a)
+        s += 'print("RV:", rv)\n'
+    s += 'vpp.disconnect()\n'
+
+    return s
+
+
+def init_api(apidir):
+    # Read API definitions
+    apifiles = VPPApiJSONFiles.find_api_files(api_dir=apidir)
+    messages = {}
+    services = {}
+    for file in apifiles:
+        with open(file) as apidef_file:
+            m, s = VPPApiJSONFiles.process_json_file(apidef_file)
+            messages.update(m)
+            services.update(s)
+    return messages, services
+
+
+def replaymsgs(vpp, msgs):
+    for m in msgs:
+        name = m['name']
+        if name not in vpp.services:
+            continue
+        if name == 'control_ping':
+            continue
+        try:
+            m['args'].pop('client_index')
+        except KeyError:
+            pass
+        if m['args']['context'] == 0:
+            m['args']['context'] = 1
+        f = vpp.get_function(name)
+        rv = f(**m['args'])
+        print('RV {}'.format(rv))
+
+
+def replay(args):
+    """Replay into running VPP instance"""
+
+    from vpp_papi import VPP
+
+    JSON = 1
+    APITRACE = 2
+
+    filename, file_extension = os.path.splitext(args.input)
+    input_type = JSON if file_extension == '.json' else APITRACE
+
+    vpp = VPP(use_socket=args.socket)
+    rv = vpp.connect(name='vppapireplay', chroot_prefix=args.shmprefix)
+    if rv != 0:
+        sys.exit('Cannot connect to VPP')
+
+    if input_type == JSON:
+        with open(args.input, 'r') as file:
+            msgs = json.load(file, object_hook=vpp_decode)
+    else:
+        msgs = apitrace2json(messages, args.input)
+
+    replaymsgs(vpp, msgs)
+
+    vpp.disconnect()
+
+
+def generate(args):
+    """Generate JSON"""
+
+    JSON = 1
+    APITRACE = 2
+    PYTHON = 3
+
+    filename, file_extension = os.path.splitext(args.input)
+    input_type = JSON if file_extension == '.json' else APITRACE
+
+    filename, file_extension = os.path.splitext(args.output)
+    if file_extension == '.json' or filename == '-':
+        output_type = JSON
+    elif file_extension == '.py':
+        output_type = PYTHON
+    else:
+        output_type = APITRACE
+
+    if input_type == output_type:
+        sys.exit("error: Nothing to convert between")
+
+    if input_type == JSON and output_type == APITRACE:
+        sys.exit("error: Input file must be JSON file: {}".format(args.input))
+
+    messages, services = init_api(args.apidir)
+
+    if input_type == JSON and output_type == APITRACE:
+        i = 0
+        for k, v in messages.items():
+            v._vl_msg_id = i
+            i += 1
+
+        n, result = json2apitrace(messages, args.input)
+        print('API messages: {}'.format(n))
+        header = struct.pack(">IIB", n, len(messages), 0)
+
+        i = 0
+        msgtbl = serialize_msgtbl(messages)
+        with open(args.output, 'wb') as outfile:
+            outfile.write(header)
+            outfile.write(msgtbl)
+            outfile.write(result)
+
+        return
+
+    if input_type == APITRACE:
+        result = apitrace2json(messages, args.input)
+        if output_type == PYTHON:
+            s = json.dumps(result, cls=VPPEncoder, default=vpp_encoder)
+            x = json.loads(s, object_hook=vpp_decode)
+            s = topython(x, services)
+        else:
+            s = json.dumps(result, cls=VPPEncoder,
+                           default=vpp_encoder, indent=4 * ' ')
+    elif output_type == PYTHON:
+        with open(args.input, 'r') as file:
+            x = json.load(file, object_hook=vpp_decode)
+            s = topython(x, services)
+    else:
+        sys.exit('Input file must be API trace file: {}'.format(args.input))
+
+    if args.output == '-':
+        sys.stdout.write(s + '\n')
+    else:
+        print('Generating {} from API trace: {}'
+              .format(args.output, args.input))
+        with open(args.output, 'w') as outfile:
+            outfile.write(s)
+
+def general(args):
+    return
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--debug', action='store_true',
+                        help='enable debug mode')
+    parser.add_argument('--apidir',
+                        help='Location of JSON API definitions')
+
+    parser.set_defaults(func=general)
+    subparsers = parser.add_subparsers(title='subcommands',
+                                       description='valid subcommands',
+                                       help='additional help')
+
+    parser_convert = subparsers.add_parser('convert',
+                                           help='Convert API trace to JSON or Python and back')
+    parser_convert.add_argument('input',
+                                help='Input file (API trace | JSON)')
+    parser_convert.add_argument('output',
+                                help='Output file (Python | JSON | API trace)')
+    parser_convert.set_defaults(func=generate)
+
+
+    parser_replay = subparsers.add_parser('replay',
+                                          help='Replay messages to running VPP instance')
+    parser_replay.add_argument('input', help='Input file (API trace | JSON)')
+    parser_replay.add_argument('--socket', action='store_true',
+                               help='use default socket to connect to VPP')
+    parser_replay.add_argument('--shmprefix',
+                               help='connect to VPP on shared memory prefix')
+    parser_replay.set_defaults(func=replay)
+
+    args = parser.parse_args()
+
+    if args.debug:
+        logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
+
+    args.func(args)
+
+
+main()