Yelnil Gabo is an Ex-Meta Software Engineer, where he served as a key technical contributor within the New Shopping Experience organization, specializing in promotional advertising systems that power merchant growth across one of the world's largest social commerce platforms. In just eighteen months, Yelnil established himself as a driving force behind email capture innovation, promotional ads experimentation, and infrastructure efficiency—delivering features that measurably expanded advertiser reach, improved user engagement, and generated significant incremental revenue for the platform's commerce ecosystem. His work spans the full stack of promotional advertising technology, from backend eligibility systems and performance instrumentation to frontend experience optimization and AI-powered tooling. Recognized by peers and leadership alike for his technical rigor, collaborative approach, and relentless focus on business outcomes, Yelnil exemplifies the intersection of engineering excellence and product impact at scale.
Projects
Four things I designed, built, and ship on my own time — from tracking market-moving voices to auditing job postings to drilling coding mechanics to building a Roblox monster-creation game.
Markets · LLM · Data pipeline
Which public-figure posts move markets — and by how much?
Ingests public-figure posts plus official Federal Register actions, extracts affected stocks and industries with Claude, joins daily price bars, and serves a Feed, Timeline, and Aggregates UI with provenance.
Solo buildTypeScript · Fastify · PostgresLive
View case study Live GitHub
Scanner · LLM · Audit
Which job posts on BC's public board are real — and which aren't?
Scores all 16,785 WorkBC postings for genuine local-hire intent, with brand-impersonation detection and a per-posting audit trail.
Solo buildNext.js · Postgres · ClaudeLive
View case study Live GitHub
Game · Roblox · Luau
A Roblox game where the lab you build gates what you can create.
48 discoveries over twelve monster families, four lab tiers, and five machines — a social Central Campus around a Personal Lab that grows from Garage to Forbidden chamber.
Solo buildLuau · Rojo · StudioIn development
View case study GitHub
Practice · Judge · C++ / Python / JS
You can explain DP — but can you type the table?
54 small judged exercises that drill the mechanics every solution starts with: 2D vectors, adjacency lists, DSU, Fenwick trees. In C++, Python, or JavaScript, with instant verdicts.
Solo buildNext.js · Prisma · Judge0Live
View case study Live GitHubTiny things
Prep guides and visualizers too small to be Projects — kept in one index so they are easy to find.
Type two rectangles, see the overlap math update live.
Paste an edge list, see the tree hang below the dragged node.
Five C++ deep dives, taught from scratch.
Impact
01 — Revenue
Yelnil architected and delivered critical components of Meta's email capture advertising system, enabling merchants to build direct customer relationships through seamless email subscription experiences embedded within promotional ads. He owned the end-to-end backend implementation and experimentation for email capture Ads Insights, culminating in the launch of a feature that surfaces email sign-up lead counts directly within the advertiser dashboard—giving merchants unprecedented visibility into campaign performance. His technical contributions extended to inline bottom sheet rendering, smart offer selection algorithms, and asynchronous entity creation flows that reduced latency and improved conversion rates. The email capture systems Yelnil built now serve as foundational infrastructure for merchant communication strategies across multiple commerce platforms, driving measurable increases in lead generation and downstream customer engagement.
02 — AI Tooling
Yelnil contributed to the organization's adoption of AI-assisted development by reviewing and enriching contextual documentation files that power intelligent code generation and analysis tools. His domain expertise in email capture systems, smart selection algorithms, and promotional ads UI patterns informed the creation of high-quality context files now used across the engineering organization. This work exemplifies Yelnil's commitment to force-multiplying his impact—not just shipping features himself, but enabling teammates and AI systems to work more effectively. The AI context initiative he contributed to has become a model for other teams seeking to leverage intelligent tooling while preserving institutional knowledge.
03 — Reach
Yelnil played a pivotal role in expanding promotional advertising capabilities to new merchant ecosystems, most notably through the WooCommerce email capture integration. This initiative alone unlocked an estimated quarter-million dollars in daily eligible advertising revenue by extending email capture functionality to a previously underserved segment of e-commerce merchants. He additionally implemented recommended offer prepopulation within the advertising management interface, streamlining the advertiser workflow and contributing to a 5.5% improvement in offer adoption rates. These strategic expansions demonstrate Yelnil's ability to identify high-leverage opportunities and execute with precision, translating technical implementation into tangible business growth. His work directly supports Meta's mission to make promotional advertising accessible and effective for merchants of all sizes.
04 — Experiments
A cornerstone of Yelnil's impact has been his ownership of experimentation infrastructure and analysis for the promotional ads domain. He designed, launched, and analyzed multiple high-stakes experiments—including quality-aware offer experiences, ratings and reviews integrations, and inline rendering optimizations—providing the data foundation for product roadmap decisions affecting millions of ad impressions daily. Yelnil authored comprehensive experiment review documentation that became templates for the broader organization, incorporating flow diagrams, gating strategies, and rigorous statistical frameworks. His analysis of social context coverage directly informed workstream prioritization for subsequent planning cycles, ensuring engineering resources were allocated to the highest-impact opportunities. This experimentation discipline has accelerated the team's ability to iterate confidently and ship winning features faster.
05 — Infrastructure
Beyond feature development, Yelnil delivered substantial infrastructure efficiency wins that reduced operational costs while improving system reliability. His optimization efforts achieved a 22% reduction in baseline compute utilization (BCU) and eliminated over $175,000 in annual compute expenses—resources that were reallocated to growth-oriented initiatives. He developed diagnostic tooling suites comprising eight new scripts for email capture systems, enabling rapid troubleshooting of offer validity, quality thresholds, performance metrics, and eligibility determination. Yelnil also addressed systemic test reliability issues, fixing flaky tests through improved mocking strategies and ensuring consistent CI/CD pipeline performance. These infrastructure contributions compound over time, enabling faster development cycles, reduced on-call burden, and more predictable system behavior at scale.
06 — Quality
Yelnil established testing patterns that elevated code quality across the promotional ads codebase. He implemented comprehensive test target frameworks and reduction tests for critical UI components, covering single-coupon footers, multi-coupon experiences, codeless flows, and bottom sheet interactions. His approach to test architecture emphasized both coverage breadth and execution reliability, creating reusable patterns adopted by teammates across adjacent workstreams. Through meticulous code review—recognized by peers for thoroughness on large, complex changesets—Yelnil ensured that technical debt was addressed proactively and that new features met the organization's quality bar. This investment in testing infrastructure has paid dividends in reduced regression rates and increased deployment confidence for the entire team.
Leadership
Yelnil demonstrates technical leadership through architectural decision-making that balances immediate delivery with long-term maintainability. His refactoring of promotional ads eligibility logic—extracting reusable traits, defining clear allow/deny rule hierarchies, and implementing eight new deny rules for diverse promotional scenarios—exemplifies this approach. Rather than accumulating technical debt through expedient fixes, Yelnil invested in systematic improvements that made the codebase more extensible for future product requirements.
His technical reviews consistently elevate the quality of team output. Colleagues note his ability to identify gaps in logging, request clarifying comments for complex logic, and catch edge cases in early return patterns—all while maintaining velocity. Yelnil's review feedback directly shaped the robustness of email unification systems, async dispatch mechanisms, and viewer context handling across surfaces.
Yelnil also demonstrates strong judgment in performance engineering, implementing QPL (performance logging) instrumentation gated by development flags to enable data-driven optimization without production overhead. His deep-dive investigations—such as the analysis of non-Shopify autofill code injection gaps—showcase his ability to trace complex system behaviors across parallel subsystems and propose actionable solutions.
Influence
Yelnil's impact at Meta extends beyond his individual technical contributions to the cross-functional partnerships that move complex projects forward. He led the cross-functional team through the Email Capture Ad Insights metrics review process, gathering technical evidence around mismatch rates, consistency, testing, and monitoring requirements, and defending the work to approval after only one follow-up cycle. This kind of XFN orchestration—building alignment with metrics reviewers, partner engineers, and product managers—has become a signature of how Yelnil delivers, ensuring that technical work translates into organizationally sanctioned outcomes rather than stalling at the review gate.
His collaboration with partner teams has consistently unlocked new platform surfaces and capabilities. Yelnil expanded email capture from Shopify-only to WooCommerce, rolling out to the full WooCommerce user base in the second half of 2025 and adding an estimated quarter-million dollars in daily eligible revenue. In a parallel effort with the Offer Manager team, he built a new metadata parser that improved offer data accuracy across roughly fifteen percent of footer loads and unblocked downstream experiments delivering topline sales impact. He has additionally provided knowledge transfer and code review to the WhatsApp Capture team as they integrated Promotional Ads functionality into a new surface.
Within his own organization, Yelnil has invested deliberately in mentoring and knowledge sharing. He runs onboarding and code-pointer syncs for engineers ramping onto the team, covering experiment execution, system context, metrics review, and international expansion. He has delivered New Bets tech talks on Ad Insights and Promotional Ads data types, lifting the broader organization's understanding of the systems he owns. Together, these contributions reflect a posture of force-multiplied impact: Yelnil's work shapes not only what his team ships, but how surrounding teams understand, integrate, and extend it.
Recognition
Yelnil has received consistent recognition from peers and leadership across multiple dimensions:
Leadership feedback highlighted Yelnil's growth trajectory and resilience, noting his ability to learn from challenges, adjust approaches, and consistently deliver against expectations. His balanced contributions across project impact, engineering excellence, technical direction, and people development position him as a well-rounded contributor with increasing organizational influence.
Closing
I'm driven by the belief that great engineering creates compounding value—not just through the features I ship today, but through the systems, patterns, and knowledge that enable tomorrow's innovations. My work at Meta reflects a commitment to building technology that empowers merchants to grow their businesses, helps users discover relevant offers, and strengthens the economic engine of social commerce worldwide.
Looking ahead, I'm focused on deepening my expertise in AI-driven advertising optimization, growing my technical leadership, and mentoring the next generation of engineers tackling complex problems at scale. I'm drawn to the intersection of engineering excellence and business impact—shipping code that not only works, but moves metrics, delights users, and creates lasting value.
Whether I'm architecting systems that serve billions of requests, analyzing experiments that inform multi-million-dollar product decisions, or building tools that accelerate my teammates, I approach every challenge with curiosity, rigor, and an unwavering focus on outcomes. I'm currently exploring my next opportunity, and I'd love to join a team building technology that matters.
Contact
Open to new opportunities. Reach out about roles, referrals, or technical conversations.