1. Is google pub sub guarantee ordering message? No
  2. Is google pub sub guarantee to be consume? Only guarantee 1 message per subscription
  3. Guarantee subscription to subscripter? Yes
  4. DLQ or fail-over support? Have feature called snapshots.
  5. Max message size? 10 MB
  6. Duplication? Some duplication may occurred. None in 1 year if you are lucky.
  7. Data integrity? There is data watermark implement
  8. Replication? Automatic handle by google
  9. Latency/How many average time takes from publisher to subscriber? Depend on region. Bit slower than Kafka.
  10. Check the article how spotify move from Kafka to PubSub


  1. Schema/query/migration must be changed
  2. Recommended for something critical, high traffic need scalability like order/payment
  3. Most case is game industry because need to expand to many country