Alex Rivera

Reduced API latency by 60% with connection pooling

Project: Platform

Profiled our API endpoints and identified database connection overhead as the main bottleneck. Implemented PgBouncer connection pooling and rewrote our query layer to use prepared statements. P95 latency dropped from 320ms to 125ms. The change also reduced our database CPU usage by 40%, saving us from an expensive RDS upgrade.

Feb 10, 2026

PostgreSQL, Node.js

“This improvement was a game-changer for our users. Alex drove the entire investigation and implementation independently.” — Sarah Chen

Mentored two junior engineers through their first production releases

Paired with Dev and Amira on their first major features. Set up a weekly 1:1 cadence to review their designs, coached them through code review feedback, and walked them through our deployment pipeline. Both shipped on time with zero rollbacks. Dev mentioned in his review that the mentoring helped him feel confident owning features independently.

Jan 20, 2026

Leadership

Led migration from Stripe v2 to v3 with zero downtime

Project: Billing

Planned and executed our payment processing migration from Stripe API v2 to v3. Coordinated across backend, QA, and customer support teams. Used a feature flag to gradually shift traffic over 48 hours while monitoring error rates. Zero customer impact, and the improved webhook handling in v3 reduced failed payment retries by 23%.

Dec 5, 2025

Node.js, System Design

“Flawless execution on a high-risk migration. Alex coordinated three teams and we had zero customer impact.” — Marcus Johnson

Designed event-driven architecture for real-time notifications

Project: Platform

Wrote an RFC proposing we move from polling to an event-driven architecture for notifications using WebSockets and a message queue. Presented to the CTO and principal engineers. Got unanimous approval. Built the initial implementation that now powers instant endorsement alerts, comment replies, and system notifications across the product.

Oct 15, 2025

System Design, TypeScript

“The architecture proposal was thorough and well-reasoned. It set the foundation for our entire real-time feature set.” — Priya Patel

Championed testing initiative, raising coverage from 40% to 78%

Identified that our low test coverage was the root cause of recurring regressions. Set up Vitest with proper mocking patterns, wrote a testing best-practices guide, and ran two lunch-and-learn sessions. Over 8 weeks the team collectively added 280 new tests. Bug reports from QA dropped 35% in the following quarter.

Aug 20, 2025

TypeScript, Node.js

Rebuilt customer dashboard in React, cutting load time by 3x

Project: Dashboard

The legacy jQuery dashboard was our most-complained-about feature. Rewrote it from scratch in React with TanStack Query for data fetching and proper loading states. Page load time went from 6s to 1.8s. Customer satisfaction scores for the dashboard section improved from 3.2 to 4.6 out of 5 in the next survey.

Apr 10, 2024

React, TypeScript

“The new dashboard was the most-requested feature by our customers. Alex delivered it ahead of schedule and the feedback has been overwhelmingly positive.” — Sarah Chen

Implemented role-based access control for multi-tenant API

Project: Core API

Designed and built a granular RBAC system supporting 5 role types across tenant boundaries. Replaced the ad-hoc permission checks scattered through the codebase with a centralized middleware. Wrote comprehensive tests covering all permission combinations. This unblocked our enterprise sales team who had been waiting on proper tenant isolation for 6 months.

Nov 15, 2023

Node.js, PostgreSQL

Introduced trunk-based development, increasing deploy frequency to daily

Our long-lived feature branches were causing painful merge conflicts and slow releases. Proposed trunk-based development with feature flags. Set up CI to run on every push to main, configured feature flags with LaunchDarkly, and trained the team in the new workflow. Deploy frequency went from biweekly to daily, and merge conflicts nearly disappeared.

Jun 22, 2023

Leadership

Endorsed by Marcus Johnson

Built automated database migration pipeline

Project: Core API

Created an automated migration pipeline that validates schema changes against a shadow database before applying to production. Integrated it into our CI/CD flow so migrations run automatically on deploy. Eliminated the manual Friday afternoon migration ritual that had caused two outages in the previous quarter.

Aug 10, 2022

PostgreSQL, System Design