diff --git a/apps/epp_proxy/test/tcp_client_SUITE.erl b/apps/epp_proxy/test/tcp_client_SUITE.erl
new file mode 100644
index 0000000..f4384ec
--- /dev/null
+++ b/apps/epp_proxy/test/tcp_client_SUITE.erl
@@ -0,0 +1,184 @@
+-module(tcp_client_SUITE).
+
+-include("epp_proxy.hrl").
+-include_lib("common_test/include/ct.hrl").
+
+-export([all/0]).
+-export([init_per_suite/1, end_per_suite/1]).
+-export([frame_size_test_case/1,
+         greetings_test_case/1,
+         session_test_case/1,
+         valid_command_test_case/1,
+         invalid_command_test_case/1,
+         error_test_case/1]).
+
+all() ->
+    [frame_size_test_case,
+     greetings_test_case,
+     session_test_case,
+     valid_command_test_case,
+     invalid_command_test_case,
+     error_test_case].
+
+init_per_suite(Config) ->
+    application:ensure_all_started(epp_proxy),
+    application:ensure_all_started(hackney),
+    Options = [binary,
+               {active, false}],
+    [{tcp_options, Options} | Config].
+
+end_per_suite(Config) ->
+    application:stop(epp_proxy),
+    application:stop(hackney),
+    Config.
+
+%% Test Cases
+frame_size_test_case(Config) ->
+    Options = proplists:get_value(tcp_options, Config),
+    {ok, Socket} = gen_tcp:connect("localhost", 1180, Options, 2000),
+    {ok, Data} = gen_tcp:recv(Socket, 0, 1200),
+    true = (byte_size(Data) =:= length_of_data(Data)),
+    ok.
+
+greetings_test_case(Config) ->
+    Options = proplists:get_value(tcp_options, Config),
+    {ok, Socket} = gen_tcp:connect("localhost", 1180, Options, 2000),
+    Data = receive_data(Socket),
+    match_data(Data, "<greeting>"),
+    ok.
+
+session_test_case(Config) ->
+    Options = proplists:get_value(tcp_options, Config),
+    {ok, Socket} = gen_tcp:connect("localhost", 1180, Options, 2000),
+    _Data = receive_data(Socket),
+    ok = send_data(login_command(), Socket),
+    LoginResponse = receive_data(Socket),
+    match_data(LoginResponse, "Command completed successfully"),
+    match_data(LoginResponse, "ccReg-5886259930"),
+    LogoutCommand =
+        <<"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n"
+          "<epp xmlns=\"https://epp.tld.ee/schema/epp-ee-1.0.xsd\">\n"
+          "<command>\n"
+          "<logout>\n"
+          "<clID>test_bestnames</clID>\n"
+          "<pw>testtest</pw>\n"
+          "<options>\n"
+          "<version>1.0</version>\n"
+          "<lang>en</lang>\n"
+          "</options>\n"
+          "<svcs>\n"
+          "<objURI>https://epp.tld.ee/schema/domain-eis-1.0.xsd</objURI>\n"
+          "<objURI>https://epp.tld.ee/schema/contact-ee-1.1.xsd</objURI>\n"
+          "<objURI>urn:ietf:params:xml:ns:host-1.0</objURI>\n"
+          "<objURI>urn:ietf:params:xml:ns:keyrelay-1.0</objURI>\n"
+          "</svcs>\n"
+          "</logout>\n"
+          "</command>\n"
+          "</epp>\n">>,
+    ok = send_data(LogoutCommand, Socket),
+    LogoutResponse = receive_data(Socket),
+    match_data(LogoutResponse,
+               "Command completed successfully; ending session"),
+    %% After receiving logout, connection should be closed.
+    {error, closed} = receive_data(Socket),
+    ok.
+
+valid_command_test_case(Config) ->
+    Options = proplists:get_value(tcp_options, Config),
+    {ok, Socket} = gen_tcp:connect("localhost", 1180, Options, 2000),
+    _Data = receive_data(Socket),
+    ok = send_data(login_command(), Socket),
+    _LoginResponse = receive_data(Socket),
+    PollCommand =
+        <<"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n"
+          "<epp xmlns=\"https://epp.tld.ee/schema/epp-ee-1.0.xsd\">\n"
+          "<command>\n"
+          "<poll op=\"req\"/>\n"
+          "<clTRID>foo bar baz</clTRID>\n"
+          "</command>\n"
+          "</epp>\n">>,
+    ok = send_data(PollCommand, Socket),
+    PollResponse = receive_data(Socket),
+    match_data(PollResponse,
+               "Command completed successfully; no messages"),
+    ok.
+
+%% Sending an invalid command frame should close the connection.
+%% It also crashes the process.
+invalid_command_test_case(Config) ->
+    Options = proplists:get_value(tcp_options, Config),
+    {ok, Socket} = gen_tcp:connect("localhost", 1180, Options, 2000),
+    _Data = receive_data(Socket),
+    ok = send_data(login_command(), Socket),
+    _LoginResponse = receive_data(Socket),
+    InvalidCommand =
+        <<"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n"
+          "<epp xmlns=\"https://epp.tld.ee/schema/epp-ee-1.0.xsd\">\n"
+          "<command>\n"
+          "<fooo op=\"req\"/>\n"
+          "<clTRID>foo bar baz</clTRID>\n"
+          "</command>\n"
+          "</epp>\n">>,
+    ok = send_data(InvalidCommand, Socket),
+    {error, closed} = receive_data(Socket),
+    ok.
+
+error_test_case(Config) ->
+    Options = proplists:get_value(tcp_options, Config),
+    {ok, Socket} = gen_tcp:connect("localhost", 1180, Options, 2000),
+    _Data = receive_data(Socket),
+    ok = send_data(login_command(), Socket),
+    _LoginResponse = receive_data(Socket),
+    InvalidXml =
+        <<"</epp>\n">>,
+    ok = send_data(InvalidXml, Socket),
+    ErrorResponse = receive_data(Socket),
+    match_data(ErrorResponse,
+               "Command syntax error."),
+    ok.
+
+%% Helper functions:
+length_of_data(Data) ->
+    EPPEnvelope = binary:part(Data, {0, 4}),
+    ReportedLength = binary:decode_unsigned(EPPEnvelope, big),
+    ReportedLength.
+
+send_data(Message, Socket) ->
+    Length = epp_util:frame_length_to_send(Message),
+    ByteSize = <<Length:32/big>>,
+    CompleteMessage = <<ByteSize/binary, Message/binary>>,
+    ok = gen_tcp:send(Socket, CompleteMessage).
+
+receive_data(Socket) ->
+    case gen_tcp:recv(Socket, 0, 1200) of
+        {error, Reason} -> {error, Reason};
+        {ok, Data } ->
+            EppEnvelope = binary:part(Data, {0, 4}),
+            ReportedLength = binary:decode_unsigned(EppEnvelope, big),
+            binary:part(Data, {byte_size(Data), 4 - ReportedLength})
+        end.
+
+match_data(Data, Pattern) ->
+    {ok, MatchPattern} = re:compile(Pattern),
+    {match, _Captured} = re:run(Data, MatchPattern).
+
+login_command() ->
+    <<"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n"
+      "<epp xmlns=\"https://epp.tld.ee/schema/epp-ee-1.0.xsd\">\n"
+      "<command>\n"
+      "<login>\n"
+      "<clID>test_bestnames</clID>\n"
+      "<pw>testtest</pw>\n"
+      "<options>\n"
+      "<version>1.0</version>\n"
+      "<lang>en</lang>\n"
+      "</options>\n"
+      "<svcs>\n"
+      "<objURI>https://epp.tld.ee/schema/domain-eis-1.0.xsd</objURI>\n"
+      "<objURI>https://epp.tld.ee/schema/contact-ee-1.1.xsd</objURI>\n"
+      "<objURI>urn:ietf:params:xml:ns:host-1.0</objURI>\n"
+      "<objURI>urn:ietf:params:xml:ns:keyrelay-1.0</objURI>\n"
+      "</svcs>\n"
+      "</login>\n"
+      "</command>\n"
+      "</epp>\n">>.
diff --git a/config/test.config b/config/test.config
index 6b9b707..921619e 100644
--- a/config/test.config
+++ b/config/test.config
@@ -1,6 +1,6 @@
 [
-  {epp_proxy, [{dev_mode, false},
-               {tcp_port, 3333},
+  {epp_proxy, [{dev_mode, true},
+               {tcp_port, 1180},
                {tls_port, 1443},
 
                {epp_session_url, "http://localhost:9292/session/"},