Design Jira's Real-Time Collaborative Issue Tracker at Scale

Problem

Design the core backend for Jira — a collaborative project management and issue tracking system.

Requirements

Functional:

• Create/update/delete issues with custom fields
• Real-time collaboration: two users editing the same issue simultaneously
• Commenting, @mentions, and notifications
• Powerful JQL (Jira Query Language) search
• Workflow state machine per issue type

Non-functional:

• 10M teams, 200M issues
• Search < 500ms
• Update propagation to collaborators < 1s

Discussion points

1. Data model: flexible custom fields without schema explosion
2. Conflict resolution for concurrent edits (OT or CRDT)
3. Search: Elasticsearch index design for JQL
4. Notification fan-out for large project teams
5. Workflow engine: state transitions with guards and validators