Whatsapp System Design and Chat Messaging Architecture (Part 1)

  • One to one Chat — You can make a chat with your friends or any numbers which you have in your contacts.
  • Group Messaging — Whatsapp has Groups. Almost 200 people can enter to one group.
  • Sent + Delivered + Read receipts — Here you can see tick marks coming in based on what stage is the message on.
  • Online / Last Seen — The person is online or the person last online status
  • Image Sharing — Images are going to share with messages. Here video sharing also applied.
  • Temporary/ Permanent Chats — This is for store some messages store someplace forever. This will save your storage and so on. If you delete some chat and your friend delete the same chat, those messages are lost forever.

One to One Chat and Sent + Delivered + Read receipts

One-to-one Connection


Message Sent
Person1 sends a message to Person2 and how the message passes through the Gateway and Service
Long Polling
Message Delivered
Message Read

Online / Last Seen

How Last Reen Request passes to the Service
Last Seen Status



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