Tiffanny Hernaez

California State University Fullerton

Bachelor of Science, Computer Science

Mattel, Inc

Software Engineer

Current role

• Built catalog search and report-management API for an internal inventory service, integrating MongoDB Atlas Search to replace manual querying via MongoDB Compass, enabling the auditing team to search the catalog directly through a dedicated API.
• Designed and shipped a Redis-backed async image-generation pipeline (API wrapper, request queue, API worker, ComfyUI proxy, GCS), processing over 100 image requests/day at 90% success rate, cutting generation latency from over 3 minutes to less than 1 minute by decoupling request intake from GPU processing.
• Built and launched an internal LLM development platform (LangSmith, LangGraph on GKE, Terraform, Helm, Cloud SQL, Redis), adopted by the application team to build and evaluate 3-4 LLM applications, cutting time-to-first-eval from 4 weeks to 2-3 days.
• Developed a secure token exchange system that decoupled Shopify checkout from the personalization backend, using one-time-use tokens and CSRF-protected sessions, eliminating a class of replay and session-hijack vulnerabilities present in the prior flow.
• Built a script to audit unique container images across 6 environments for compliance with an upcoming TLS root certificate deprecation deadline, flagging at-risk services ahead of the cutoff.
• Addressed a TLS certificate chain issue identified during an audit by updating the Auth0 redirector service's CI/CD build image to trust the new root certificate and redeploying it with ArgoCD, preventing a potential login outage.
• Enhanced developer experience by contributing to a Backstage Cloud Run template that reduced new service setup from 2 days to under 1 hour, and created deployment and API troubleshooting guides that standardized endpoint testing and streamlined deployment handoffs
• Authored an architecture RFC for localized Auth0 transactional emails, defining a Contentstack webhook boundary with authentication, event filtering, version checks, duplicate handling, and recovery requirements while keeping security links and template logic under code ownership.
• Built the Chat Application integration with a deployed agent platform through server-side Netlify handlers for streaming invocation, execution status, and resume; kept platform credentials out of browser code and made deployment targets configurable by environment.
• Engineered a React and TypeScript web application integrating an AI agent and MongoDB to transform product reviews and social media data into actionable, evidence-backed insights through three interconnected workflows: real-time analysis streaming, human-in-the-loop approval, and trend exploration.
• Developed configurable image quality controls for an image generation API, centralizing quality settings through environment variables and removing client-side overrides to ensure consistent image generation.

Mattel, Inc

Associate Software Engineer

Jan 2022 - Sep 2024

• Programmed in Golang to optimize efficiency in cloud platform server infrastructure by 20% by developing and maintaining quality code that vastly enhanced the end user experience
• Developed an efficient tool to cut down 30% of time spent maintaining a product service through automation
• Facilitated a proof of concept (POC) that decreased 50% of the workload of a 3rd party vendor by researching and developing a backend service with an open source game server framework
• Improved a microservice template by adding automated OpenAPI generation, validation, and linting, and introduced an 85% pytest coverage gate in the CI pipeline to standardize new services and enforce code quality.
• Resolved a cross-region logic gap in the GDPR user deletion workflow that could allow downstream deletion to continue when a user was missing from Auth0 or a regional identity system, eliminating a data compliance risk. Validated the solution through policy-based permission provisioning, OAuth token exchange, and service account testing.
• Monitored and maintained multiple 24/7 live services by performing audits throughout the day to guarantee 99.9% uptime
• Performed deployment of code changes through the integration pipeline with the use of Jenkins and Google’s Kubernetes Engine
• Created a system to streamline over a thousand user data transformations within Mattel Connected Products Platform’s relational database structure due to a deprecated system that is no longer supported.

Software Engineer Intern

Jun 2021 - Jan 2022

• Decreased 40% of the team’s workload by commencing groundwork in research and generated code by utilizing the go-swagger tool to set up a new Artificial Intelligence of Things platform
• Empowered intern collaborations and led the process of designing a new toy concept by fostering partnerships across different departments
• Used Jira to track features and bugs and maintained documentation in Confluence.
• Enhanced PostgreSQL tables using tern, mage, and gnorm to support customization.

Amazon

IT Engineer Intern

Jun 2020 - Aug 2020

• Performed numerous supervised Change Management procedures that updated the network firmware and helped maintained the main distribution frame
• Monitored and maintained the intermediate distribution frame by performing checks throughout the day to ensure 99.9% uptime
• Increased efficiency by 60% by improving ticket creation and data accuracy through quicklink templates.
• Proposed a plan to reduce lost scanners by comparing floor counts with the inventory available to associates.

California State University Fullerton

Student Assistant for Information Technology Department (Knowledge Base Articles Team)

Mar 2019 - Jun 2020

• Implemented a Kanban Board using Microsoft Teams to help organize the newly formed team to cut down admin time by 80%
• Performed an audit on the school’s knowledge database on Service Now to streamline the database to relevant articles
• Created over 100 Knowledge Base Articles to provide support to the staff and students on campus during the transition to virtual
• Created an HTML/CSS template to be used on Knowledge Articles to cut down 50% of the time spent in creating an article

Student Assistant for Information Technology Department (Rollout Team)

Aug 2019 - Jun 2020

• Performed timely support for professors/staff from all departments on campus. Support includes deploying hardware and setup, troubleshooting network issues and collecting former equipment to be e-wasted
• Created tickets for CSUF staff on Service Now to activate the university’s secure network connection for inactive data jacks
• Imaged over a hundred secure configurations of Windows 10 on professor and staff equipment
• Replaced hardware (SSD, Screen, RAM, HDD) in Mac and Windows based environment to drastically increase the utility and speed of the equipment

Caltrans

Student Engineer Intern for Encroachment Permits

Aug 2017 - Jul 2019

• Assisted engineers by inputting, processing and issuing around 3,000 permit applications from cities, contractors, electrical companies, etc
• Assessed 15 to 20 traffic control plans, SWPP, WPCP and other plans provided by the permittees per month
• Reviewed with Caltrans’ clients/contractors the required steps to proceed in processing their permit application
• Wrote more than 2,000 professionally written denial letters that included reviewer comments and rules to abide by when doing the actual work

IT Tech Volunteer

Nov 2017 - Feb 2019

• Created an assembly line of 20 computers to mass image configurations of Windows 7 and 10 which increased the imaging process by 80%
• Deployed equipment to over a hundred government workers and provide aid on equipment set up
• Created spreadsheet inventory for equipment which cut down on misplaced hardware by 70%
• Have an understanding on Helpdesk ticketing system, Datalink