Jayson Virissimo

Engineer on a regulated platform for private-fund subscriptions, orders, and compliance (Ruby on Rails and React on AWS). Hired as Senior, promoted to Staff.

• Sole engineer and technical owner of the flagship integration with one of the largest US independent broker-dealers, from requirements and API design through launch and support: automated account and team imports, hierarchical advisor teams, and real-time licensing and training checks.
• Owned a second partner integration end to end, from requirements through launch, on a configuration-driven import pipeline built so later partners onboard with minimal custom code.
• Built pre-trade compliance checks that gate order entry on advisor registration and licensing, completed product training, and product concentration limits, covering tens of thousands of advisors across organizations.
• Hardened concurrency handling and data integrity across the integrations with advisory locks, unique background jobs, database unique constraints, idempotent migrations, and retries with backoff; fixed race conditions in account, team, and contact creation.
• Strengthened tenant isolation and organization-scoped authorization across the integrations; delivered HMAC-authenticated webhooks with constant-time verification, support for multiple SAML identity providers, and OAuth token caching.
• Led research, design, and delivery of an advisor training platform (React and Rails) that gates investment-product access on completed training.
• Owned incident response for the integration surface, from alert triage through mitigation, root-cause fixes, and coordination with partner engineers.
• Primary technical contact for partner firms: ran requirements and design sessions with their engineers and managers, and proposed API shapes the broker-dealer adopted.
• Ran zero-downtime data migrations that removed redundant association records and restructured team associations; profiled and optimized the nightly import jobs, cutting query counts by a third to two-thirds per job in profiling against production-shaped data.
• Onboarded and mentored the engineer who now owns the flagship integration, enabling a clean handoff; interviewed engineering candidates.

Senior engineer on the messaging team of a student career platform (Rails, GraphQL, React).

• Wrote architecture decision records with product managers and designers before building.
• Replaced the student and employer inbox's REST endpoints with GraphQL mutations.
• Moved expensive inbox operations out of the monolith into a messaging service.
• Introduced command objects in legacy controller actions to reduce feature rollout risk.

Managed a team of up to five engineers and four contractors that owned checkout, payments (Stripe, Affirm, PayPal), promotions, customer-experience tooling, and the retail point-of-sale system for a direct-to-consumer mattress brand, while staying hands-on in the Rails monolith.

• Prevented double charges by making payment capture transactional with order creation, holding a pessimistic lock until capture, and centralizing idempotency-key generation outside the Stripe gateway.
• Extended fraud screening from Stripe-only orders to Affirm and PayPal and reported confirmed fraud, with customer IP, to a third-party fraud service.
• Launched e-commerce sites for two additional mattress brands on the same monolith, including brand-specific configuration and CI auto-deploy pipelines.
• Built career plans with direct reports and negotiated their promotions and raises; several were promoted to Senior and have since become Staff engineers and engineering managers.

Built the checkout API, customer-experience tooling, and fulfillment automation in a Rails monolith; second-highest contributor in the codebase's history with 1,000+ commits.

• Upgraded the monolith from Rails 4.2 to 5.1 and Ruby 2.3 to 2.5, later continuing through Rails 6.0 as engineering manager.
• Designed the fallback that let orders complete during sales-tax provider outages.
• Found a SQL-injection exposure in the operations portal's search code after spotting an anomalous raw-SQL error, and closed it by sanitizing user input in the searcher classes.
• Designed key-based device authentication for retail point-of-sale terminals, with a private key provisioned over USB in place of passwords.
• Added caching and per-IP rate limiting to the public Grape API after a 2017 scraping incident degraded the site.
• Introduced automated performance testing and cut product-table queries on the cart endpoint from 22 per item to 1 per item.