Reliable chat send

  • Build
  • Pixel 14

Difficulty 4 of 5

Phones send 200 chat messages/s. The API is down for 15 s at 0:20 and answers 1.6 s late for 8 s at 0:50. Delivery runs on 4 workers. Accept every send, lose and repeat none, keep each conversation in order, and hold no message over 40 s. Budget: 60 USD/month.

Play level

HTTP/2HTTP/2Mobile users200 req/sNode API4 vCPU · 4 GBWorker
HTTP/2HTTP/2Mobile us…200 req/sNode APIWorker
The board at the start of the level
Delivered twice, charged onceTap to turn the ID check on or off

13 deliveries · 10 payments applied · 0 charged twice

Goals and limits

Error rate
under 0.1%
Lost writes
none
Duplicates
none
Out of order
none
Queue lag
under 40 s
Monthly cost
under 60 USD/mo
Parts you can add
Message broker, Kafka log
Part limit
4

Concepts

How players did

Player results load from the server.

All levels