Fortune 500 Architecture Migration

TL;DR

Led the architectural shift from monorepo to polyrepo at Eventbrite. Scaled adoption from 2 to 40 teams (90% adoption), enabling independent deployments and team autonomy.

Context

Eventbrite's monorepo architecture was becoming a liability. Teams couldn't move independently—merge conflicts were constant, deployments were coupled, and a bug in one team's code could block everyone.

Problem

• Monorepo was slowing teams down
• Constant merge conflicts between teams
• Coupled deployments—one team's issue blocked all deploys
• Teams couldn't own their deployment cadence
• Only 2 teams had migrated after months of effort

What I Did

1. Assessment: Mapped dependencies and identified migration candidates
2. Coalition Building: Built buy-in across engineering leadership for the architectural shift
3. Migration Path: Designed incremental migration that didn't disrupt active development
4. Governance Model: Created standardized templates and policies for polyrepo teams

Key Decisions

Governance Through Templates

Instead of centralized control, encoded governance into templates. Teams get autonomy within guardrails.

Incremental Migration

No big-bang migration. Teams migrated when ready, with support from the platform team.

Clear Ownership Model

Each repo has a single owning team with full deployment authority.

Technical Details

• Polyrepo Governance: Automated compliance checks, dependency management, and security policies
• Template Standardization: Consistent CI/CD, testing, and deployment patterns across all repos
• Dependency Management: Automated dependency updates and security patching
• Migration Tooling: Scripts and guides for teams migrating from monorepo

Results

• Teams deploy independently without coordinating with other teams
• Merge conflicts between teams eliminated
• Each team owns their deployment cadence

Lessons Learned

1. Migration requires coalition: Architectural changes need buy-in from leadership and clear communication to affected teams.
2. Autonomy with guardrails: Teams want freedom; platform teams need consistency. Templates bridge the gap.
3. Don't force migration: Let early adopters prove value. Success stories drive organic adoption.
4. Ownership clarity matters: Clear ownership model eliminated "whose bug is this?" debates.