Performance Engineer, Backend

About the Role: Performance Engineer, Backend at Automattic

Automattic’s extensive product portfolio, including WordPress.com, WooCommerce, Beeper, Tumblr, and Jetpack, collectively serves tens of billions of page views monthly from data centers across the globe. The PerfOps team is dedicated to ensuring these page views are delivered as quickly as possible. As a Backend Performance Engineer, you will deeply analyze query plans, cache hit ratios, and PHP profiling data to identify crucial milliseconds at our vast scale. This role offers an opportunity to work across Automattic’s entire product ecosystem, making any backend component your domain.

This position offers immediate and significant impact through performance optimization. You will collaborate closely with product engineers, systems engineers, and network operations teams, embedding a performance-first mindset into architecture decisions, code reviews, and incident response. If you enjoy solving the puzzle of slow systems and gaining satisfaction from making measurable improvements, this role is an ideal fit.

Key Responsibilities

• Identifying and resolving backend performance bottlenecks by profiling PHP applications, optimizing MySQL/MariaDB query performance, and enhancing Memcached usage across all Automattic products.
• Building and refining performance observability systems, including developing dashboards, instrumentation, and automated detection tools to catch regressions pre-production and provide engineering teams with clear, actionable data.
• Collaborating with product and platform engineers to review code and architecture from a performance perspective, championing efficient database access patterns, robust caching strategies, and optimized backend design.
• Elevating the overall performance standard across engineering by documenting best practices, contributing to internal guidelines for PHP and database performance, and mentoring teams on scalable backend code development.
• Proactively seeking out and resolving performance issues before they impact users.
• Conducting deep dives into individual sites, working with support staff and engineers to address specific customer performance challenges.

Requirements

• Deep hands-on experience with PHP performance, including profiling applications, identifying hot paths, and understanding memory usage and execution time at the code level.
• Strong understanding of caching layers and strategies, encompassing the design and debugging of Memcached (or similar) patterns, knowledge of cache invalidation trade-offs, and the ability to discern when caching truly helps versus merely masks problems.
• Proven experience with performance optimization at scale, working on systems handling millions of requests where minor inefficiencies accumulate into significant issues, and understanding the nuances between benchmark optimization and real-world production load optimization.
• A methodical approach to instrumentation, measurement, and validation, relying on data rather than assumptions. Experience with profiling tools, APM systems, and performance dashboards to transform hypotheses into concrete data and confirm the effectiveness of implemented fixes.
• Excellent written communication skills, essential for a distributed, async-first company like Automattic. You must clearly articulate complex performance findings, draft proposals, and influence engineering decisions primarily through written communication.
• Strong self-direction and ownership, enabling you to identify high-impact performance work, prioritize effectively, drive tasks to completion, and maintain accountability without constant oversight.

Bonus Points

• Hands-on experience with WordPress and WooCommerce in high-traffic production environments is highly valued.

Key skills/competency

• PHP Performance Profiling
• MySQL Optimization
• MariaDB Optimization
• Memcached Caching
• Backend Architecture
• Performance Monitoring
• System Scalability
• Code Review
• Instrumentation
• Distributed Systems