Atlassian system design interview questions

Sample questions with short answers

Tap a question to reveal the short answer and key points.

1. 1Design Jira's issue tracking backend for thousands of tenants.HardAtlassian-specificShow short answer

   Short answer

   Model issues, workflows and custom fields per tenant with a flexible schema (core columns plus a JSON or EAV extension). Isolate tenants by shard or database and route by tenant ID. Index issues in a search cluster for JQL-style queries, emit events for automation and notifications, and keep an audit log. Discuss noisy-neighbour limits and schema migrations.

   Interviewers listen for

   • per-tenant flexible schema
   • tenant sharding and routing
   • search index and event stream
2. 2How would you design a feature-flag service used by many products?MediumAtlassian-specificShow short answer

   Short answer

   Store flag definitions and targeting rules centrally, push changes to SDKs via streaming or polling with ETags, and evaluate rules client-side for low latency. Version every change with an audit trail, support percentage rollouts by hashing user IDs, and design for safe defaults when the service is unreachable.

   Interviewers listen for

   • central rules with client-side evaluation
   • percentage rollouts via hashing
   • audit trail and safe defaults
3. 3Design a URL shortener. Walk through the key decisions.MediumAsked everywhereShow short answer

   Short answer

   Clarify scale (e.g. 100M new URLs/month, 10:1 read:write) and features (custom aliases, expiry, analytics). Generate short keys with base-62 encoding of a counter or a hash with collision checks. Store the mapping in a key-value store, put a cache in front for hot links, and make redirects 301/302 depending on whether you need click analytics. Discuss sharding by key and rate-limiting abuse.

   Interviewers listen for

   • clarify scale and read/write ratio
   • base-62 key generation
   • cache for hot redirects
   • sharding the key-value store
4. 4What is the CAP theorem and how does it shape real system choices?MediumAsked everywhereShow short answer

   Short answer

   During a network partition a distributed system must choose between consistency (every read sees the latest write) and availability (every request gets a response). Banking ledgers lean CP; social feeds and shopping carts lean AP with eventual consistency. In interviews, name the partition scenario explicitly and justify which side the product can tolerate.

   Interviewers listen for

   • partition forces consistency vs availability
   • banking leans CP, feeds lean AP
   • justify choice from product tolerance
5. 5How would you design a rate limiter for an API gateway?HardAsked everywhereShow short answer

   Short answer

   Choose an algorithm — token bucket is the usual default (allows bursts, simple to reason about); sliding window log is exact but memory-heavy. Keep counters in Redis keyed by client and window, using atomic INCR/EXPIRE or a Lua script to avoid races. For multiple gateway nodes, centralise counters or accept slight over-admission with local buckets. Return 429 with Retry-After headers.

   Interviewers listen for

   • token bucket or sliding window
   • Redis counters with atomic operations
   • distributed nodes and 429 responses