diff --git a/lib/packer.rb b/lib/packer.rb
new file mode 100644
index 0000000..4acb71d
--- /dev/null
+++ b/lib/packer.rb
@@ -0,0 +1,62 @@
+class Packer
+  # poor mans int packer
+  # homebrew not covering
+  # the full tw fancyness
+  #
+  # Format: ESDDDDDD EDDDDDDD EDD... Extended, Data, Sign
+  def self.pack_int(num)
+    if num > 63 || num < -63
+      # the first byte can fit 6 bits
+      # because the first two bits are extended and sign
+      # so if you have a number bigger than 63
+      # it needs two bytes
+      # which are also least significant byte first etc
+      # so we do not support that YET
+      #
+      # the first too big number 64 is represented as those bits
+      # 10000000 00000001
+      # ^^^    ^ ^      ^
+      # ||\   /   \    /
+      # || \ /     \  /
+      # ||  \       \/
+      # ||   \      /
+      # ||    \    /
+      # ||     \  /
+      # ||      \/
+      # ||      /\
+      # ||     /  \
+      # ||    /    \
+      # || 00000001 000000
+      # ||       |
+      # ||       v
+      # ||       64
+      # ||
+      # |positive
+      # extended
+      raise "Numbers greater than 63 are not supported yet"
+    end
+    sign = '0'
+    if num.negative?
+      sign = '1'
+      num += 1
+    end
+    num = num.abs
+    ext = '0'
+    bits = ext + sign + num.to_s(2).rjust(6, '0')
+    [bits.to_i(2)]
+  end
+end
+
+def todo_make_this_rspec_test
+  p Packer.pack_int(1) == [1]
+  p Packer.pack_int(16) == [16]
+  p Packer.pack_int(63) == [63]
+
+  p Packer.pack_int(3) == [3]
+  p Packer.pack_int(-1) == [64]
+  p Packer.pack_int(-2) == [65]
+
+  # todo
+  # p Packer.pack_int(64) == [64]
+end
+
diff --git a/lib/teeworlds-client.rb b/lib/teeworlds-client.rb
index fb61e8c..641ce04 100644
--- a/lib/teeworlds-client.rb
+++ b/lib/teeworlds-client.rb
@@ -10,6 +10,7 @@ require_relative 'packet'
 require_relative 'chunk'
 require_relative 'server_info'
 require_relative 'net_base'
+require_relative 'packer'
 
 class TwClient
   attr_reader :state
@@ -102,13 +103,48 @@ class TwClient
   end
 
   def send_msg_startinfo()
-    # todo: build startinfo chunk here
+    start_info = {
+      name: "ruby gamer",
+      clan: "",
+      country: 1,
+      body: "spiky",
+      marking: "duodonny",
+      decoration: "",
+      hands: "standard",
+      feet: "standard",
+      eyes: "standard",
+      custom_color_body: 0,
+      custom_color_marking: 0,
+      custom_color_decoration: 0,
+      custom_color_hands: 0,
+      custom_color_feet: 0,
+      custom_color_eyes: 0,
+      color_body: 0,
+      color_marking: 0,
+      color_decoration: 0,
+      color_hands: 0,
+      color_feet: 0,
+      color_eyes: 0
+    }
 
-    # create unused chunk just to bump
-    # the sequence number ._.
-    NetChunk.create_vital_header({vital: true}, 1)
+    data = []
 
-    @netbase.send_packet(MSG_STARTINFO)
+    start_info.each do |key, value|
+      if value.class == String
+        data += value.chars.map(&:ord) + [0x00]
+      elsif value.class == Integer
+        data += Packer.pack_int(value)
+      else
+        puts "Error: invalid startinfo #{key}: #{value}"
+        exit 1
+      end
+    end
+
+    @netbase.send_packet(
+      NetChunk.create_vital_header({vital: true}, data.size + 1) +
+      [pack_msg_id(NETMSGTYPE_CL_STARTINFO, system: false)] +
+      data
+    )
   end
 
   def send_msg_ready()