Jeremy Bargar, Developer in New York, NY, United States
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Jeremy Bargar

Verified Expert  in Engineering

Full-stack Developer

New York, NY, United States
Toptal Member Since
October 30, 2020

Jeremy is a hybrid full-stack coder with UI design sensibility and wide-ranging experience in front-end and enterprise projects specializing in JavaScript. Thanks to over 20 years of programming experience, Jeremy is comfortable in all aspects of app development, including design, mockups, prototypes, UI and server-side implementations, build processes, testing, refactoring, and maintenance.


Vue, BNF, Nearley
Vue, changesets, Monorepos, Swift, Bitbucket, Nuxt.js
The Trade Desk
React, React Testing Library, Highcharts, Redux, Redux Form, React Spectrum...




Preferred Environment

Google Cloud Platform (GCP), MacOS, WebStorm, Sequelize, GraphQL, PostgreSQL, Node.js, React, JavaScript

The most amazing...

...project I've done was building a customer service framework that tracked orders, processed payments and refunds, and ingested REST, BigQuery, and GraphQL data.

Work Experience

Software Architect

2019 - PRESENT
  • Rewrote and expanded SpecWizard feature, which creates complete 3-part CSI construction product specifications based on user inputs that can be freely generated and downloaded as PDF and other formats. Used Node.js/Vue 2 (originally written in Perl).
  • Rewrote rendering of interactive specification forms based on custom HTML-like syntax, maintained compatibility with around 1,000 existing SpecWizards, parsed and validated using new BNF grammar and evaluator written for the nearley parsing toolkit.
  • Wrote new features: alert users mid-edit when conditional validation is violated and direct them to the relevant fields for remedy, inline dynamic debugging tools for SpecWizard authors, automated test suite, made possible by more modular design.
Technologies: Vue, BNF, Nearley

Staff Software Engineer

2022 - 2023
  • Built client-facing Vue 3 UI to manage video content including video, clip and collections viewing and editing. Customized sidebase/nuxt-auth library to support domain-based multi-tenancy. Dark mode support.
  • Enabled easy code reuse across projects by setting up monorepo, separating out shared libraries and apps. Semantic versioning with changesets library. Hand-rolled Bitbucket CI pipelines publishing to npm, linting and verifying Vue production builds.
  • Upgraded Yarn iOS apps (full and messenger tray UI) to work with current Swift and iOS versions, making it possible to publish new versions to the app store. Updated look and feel of iOS apps with new designs and branding.
  • Feature work for, including authorization bugfixes, meta tag and sharing fixes in Vue 2.
  • Video processing pipeline improvements, invoking Google cloud functions from existing Rails code.
  • Evaluated react-admin as possible internal admin UI.
Technologies: Vue, changesets, Monorepos, Swift, Bitbucket, Nuxt.js

Senior Software Engineer

2020 - 2022
The Trade Desk
  • Wrote Advertising Insights UI in React for at-a-glance understanding of ad campaign demographics, including responsive Highcharts charting taking advantage of both large screen trader and standard desktops.
  • Helped implement React context-based form solution to replace widespread usage of deprecated ReduxForm library.
  • Designed and implemented comprehensive react-testing-library test suite. Improved test suite performance. Analyzed test run heap profiles with flame graphs to identify slow tests and optimized generically, halving overall test suite run time.
  • Wrote UI surfacing ad campaign spending blockers, empowering users to find instances where their campaigns were not executing and allowing them to make the necessary adjustments to get back on track.
  • Contributed to internal component library used across multiple apps and based on design system. Modular software design where UI component function and accessibility are separated from styling, based on React Spectrum.
  • One of the many contributors to Solimar project, a rewrite of the entire ad trading UI with significant look and feel and productivity updates.
Technologies: React, React Testing Library, Highcharts, Redux, Redux Form, React Spectrum, changesets, Grafana, TypeScript, JavaScript, C#

UI Architect

2020 - 2020
Bed Bath & Beyond
  • Designed and built a dynamic pricing front-end app to execute pricing strategy, easing bottlenecks of hand-written queries by two power-users to execute changes on behalf of a group of 20.
  • Empowered pricing analysts by providing data in context rather than in a legacy database. Visualized date ranges for pricing strategies on a Gantt timeline, dramatically easing scheduling.
  • Managed ticketing with Clubhouse, source code testing and linting with GitHub actions, and deployment as a single Docker image to multiple Google Cloud Platform environments.
  • Reviewed code and made occasional contributions to a Rails JSON API standard back end.
  • Wrote a 30-page user manual covering all features with text and screenshots.
  • Built a prototype of a SAS task-based UI, demonstrating the need for a richer solution to business partners.
Technologies: SQL, Service Workers, Server Sent Events (SSE), PostgreSQL, Ruby on Rails (RoR), Clubhouse, GitHub Actions, Docker, JSON API, Gantt Charts, MUI (Material UI), React Testing Library, React Hooks, React

Web UI and Full-stack Architect

2019 - 2020
  • Designed and built the customer service and operations web app which tracked the order lifecycle from placement to fulfillment and returns, offering a fast lookup to CX reps live on phone with customers (React front end, Node.js GraphQL back end).
  • Replaced a scripted billing and manual refund system with an automated system to calculate and execute charges and refunds for orders with refund business logic unique to Buffy. Integrated with Shopify and validated with a large test suite.
  • Wrote a Node.js app to ingest Shopify eCommerce storefront data in real-time and with periodic reconciliation after the initial historical backfill. Data sources include webhooks, REST API calls, GraphQL API calls, JSON files, and BigQuery datasets.
  • Stood up all of the above on Google Cloud Platform, including running apps in App Engine and Compute Engine, Google Cloud Build CI (testing, data migrations, and deployment), and SQL and BigQuery data.
  • Created a working demo of the customer-facing bed building UI—selecting products, sizes, and colors and adding to cart in fewest clicks possible. Written with Gatsby and backed by Shopify API.
  • Helped build our team, including interviewing, training, pairing, processing, and code reviews.
Technologies: Balsamiq Mockups, SQL, Grommet, Gatsby, Shopify API, Google App Engine, Google Cloud Build, BigQuery, Sequelize, PostgreSQL, GraphQL, Node.js, React

Search API and UI Consultant

2019 - 2019
Bed Bath & Beyond
  • Contributed to Universal Product Catalog web app—offering a single, modern view into SKUs across all brands. Enriched the Solr search index and Rails API providing access to it.
  • Refactored the API for maintainability and readability, replacing verbose field configuration with a DSL and ruthlessly removing adapters of little utility and requiring high effort maintenance.
  • Wrote a monitoring framework for catalog indexing—recording audit data for periodic batch processes, keeping the catalog up to date, writing a React front end to inspect individual runs, and watching for longer-term timing trends.
Technologies: SQL, Google Cloud Platform (GCP), Solr, React, Ruby on Rails (RoR)

Web and iOS Tech Lead

2017 - 2019
One Kings Lane
  • Built productivity UIs like SKU Exporter, Rosetta SKU, and Price Change Approvals in Vue.js while maintaining and improving extensive Rails codebase. Accelerated common workflows and humanized "engineer-designed" UIs.
  • Rescued delayed customer-facing iOS app, launching in time for the 2018 holiday season. Technically managed the project, ensured delivery of data APIs by a partner. Used Swift and rewrote major features (product detail page and category navigation).
  • Helped build the team, including interviewing, training, pairing, processes, and code reviews.
Technologies: SQL, iOS, Swift, Vue, Ruby on Rails (RoR)

Search and Analytics UI Architect

2016 - 2017
  • Built enterprise analytics dashboards for sales and marketing users, providing insights regarding consumption trends, contribution, content effectiveness, and revenue attribution.
  • Developed an enterprise admin dashboard for easy management of users, teams, and topics as well as insights into document types and processing.
  • Created extensive charting using Highcharts including live filtering and full-screen views.
  • Integrated recommended content and activity timeline directly inside the Salesforce UI.
  • Developed a document search UI including a single search box with automatic filter inference, quick views, and sharing tools.
  • Designed and documented the API using Swagger and wrote a small web app to make available privately to the team.
Technologies: Jira, Salesforce, Ruby on Rails (RoR), Swagger, Highcharts, Ember.js, JavaScript

Web UI Architect

2014 - 2016
Flat World Education
  • Built an instructional design authoring tool for an online education platform used by the faculty to make and maintain college materials, quizzes, and exams. Architected it as an Ember.js SPA and contributed to the API back end (Ruby and Sinatra).
  • Replaced the legacy student-facing UI as well including exam UI for students vying for college credit. Leveraged the same tech stack to share components and maximize cross-team developer mobility.
  • Empowered the QA team by writing an expansive UI unit test suite, devising a mock proctoring client with Koa and NW.js to reduce testing overhead, and scripting onerous test scenarios including 100+ question exams.
  • Trained new team members in Ember.js, UI development, and Git.
Technologies: NW.js, Koa, MathJax, Ruby, QUnit, Ember.js, JavaScript

Android Consultant

2014 - 2014
  • Added several features to a social network's Android app as part of an effort to duplicate its iOS app.
  • Wrote a custom, in-app camera including preview, aspect ration management, and filter integration.
  • Added the ability to share content through Facebook and Twitter integrations.
Technologies: SQL, Java, Android

Node.js/MongoDB Consultant

2013 - 2014
  • Served as the sole engineer of a type of academic software that runs multi-user game theory simulations with merchants from the Gamarra garment district in Lima (Express.js server with Handlebars templates and MongoDB as the datastore).
  • Deployed on Heroku as a low-cost option viable for the academic setting.
  • Wrote CasperJS headless end-to-end tests to ensure the calculation of the correct outcome across a wide variety of game variants and scenarios.
Technologies: Bootstrap, CasperJS, Handlebars, MongoDB, Express.js, Node.js, Game Development

Senior UI Engineer Consultant

2013 - 2014
  • Built Nemo, a UI for salespeople in the field for hyper-efficient data entry and richer visualization of sales data (written in Ember.js with a Salesforce API back end).
  • Customized a search-as-you-type widget for based on Twitter and backed by RichRelevance's APIs.
  • Added features to RichRelevance data intelligence and ad serving administration UIs using jQuery and Java.
Technologies: SQL, jQuery, Java, Ember.js, JavaScript


2011 - 2013
Bank of America
  • Coded the document workflow system as a single-page jQuery front end with SlickGrid, pub/sub-event system, Bootstrap, and other UI design elements backed by a REST API.
  • Customized SlickGrid, a jQuery grid widget capable of handling 100,000+ rows of data in the browser. Simplified the developer API and added features like automatic, Excel-style column filtering, and multi-column sorting for target browser IE7.
  • Assisted the build team by adding and adhering to best practices using Jenkins and CI.
Technologies: SQL, jQuery, Bootstrap, SlickGrid, Jenkins, Oracle, JavaScript, Java


1996 - 2012
  • Single-handedly created the visual design and implementation of an eCommerce site including catalog, shopping cart, and checkout for a small family business started by my grandfather and continued by my father.
  • Wrote back-office features including order workflow, data entry, mini-CMS, and batch product imagery tools.
  • Tracked and fixed bugs using Mantis as a reporting tool.
Technologies: Adobe Photoshop, SQL, Microsoft Access, JavaScript, Adobe ColdFusion

Senior UI Engineer

2010 - 2011
  • Wrote ClickSee, a customer-facing visual product catalog explorer in cross-browser jQuery, presenting product images and details in a grid that can be interacted with to discover new items using RichRelevance recommendation engine under the hood.
  • Acted as company-wide UI domain expert—improving workflows, data visualizations and grids with filtering and sorting. Designed REST APIs including complete, stateful mock implementations on the server, decoupling client-side and back-end development.
  • Wrote an iTunes Cover Flow-inspired, interactive web demo of ad types, estimated traffic, and revenue.
  • Authored a web app-fronted system for running and monitoring client catalog feeds.
  • Added internationalization support to a RichRelevance recommendation engine and ad server.
Technologies: Apache Maven, SQL, REST, Guice, jQuery, Java, JavaScript


2009 - 2010
IMHO Media
  • Helped build a rich web app for managing video ad campaigns with a fully-interactive UI with jQuery dialogs and Ajax for a desktop feel.
  • Built an iTunes-like search based on dynamically-built smart playlists and catalog view with horizontal scrolling of thumbnails, Mouseover for details, live updates based on demographic targeting and rich list view with Ajax inline editing.
  • Integrated data coming from the player, analytics server, and Amazon S3.
Technologies: SQL, Ajax, Bootstrap, Grails, Groovy, JavaScript

Senior Java Consultant, Credit and Market Risk

2005 - 2009
Merrill Lynch
  • Wrote an Ajax ExtJS front end to manage users and permissions across all credit risk applications.
  • Rewrote the search entry page for flagship apps—replacing web 1.0 with Ajax data grid with server side-provided pagination, sorting, and filtering against server-side with caching.
  • Authored an Ajax auto-suggest database search developer tool.
  • Extracted ad-hoc legal document workflow business logic from templates for property file DSL.
  • Revamped the build process, source control tagging, linting, CI, and version exposed in the about page.
  • Developed a market risk system that consumed feeds served over HTTP and offered a grammar and query language as the UI for extending and reshaping the data for downstream use.
Technologies: JavaCC, SQL, Ant, Jenkins, Ext JS, Ajax, Java, JavaScript

Senior Java Consultant

2004 - 2005
Bank of America
  • Contributed to a system that manages mutual fund accounts for high net-worth individuals.
  • Created early JavaScript user interfaces, including sorting tables of data by multiple columns without a server call in DOM and retrieving data using Java JSON-RPC (XMLHttpRequest).
  • Trained and mentored junior team members in best practices.
Technologies: SQL, XMLHttpRequest, JSON-RPC, JavaScript, Java

Software Architect

2003 - 2004
  • Implemented an online video gaming league website featuring member registration, team administration, ladder rankings for game titles and types of play, individual and team challenges, protocol wizards, and back-end tools for league administrators.
  • Developed a UI to spawn new instances of game servers on the fly via a partner company API.
  • Created an integrated subscription billing system using PayPal.
Technologies: SQL, JavaScript, Enterprise Java Beans (EJB), XDoclet, PayPal, Java

Java Developer Consultant

1998 - 2002
The Information Highway Group
  • Developed business applications for a variety of international clients in English and Spanish while residing in Barcelona and Hamburg.
  • Transformed the product catalog into a multi-language, multi-region, customizable catalog generator.
  • Added features to a health portal for the government of Catalonia including a web-based web-page creation tool.
  • Developed a music play list application for PC and Windows CE mobile.
  • Contributed to an early German digital TV offering, culminating in giving technical presentation at BEA WebLogic Conference in Paris in summer 2000.
  • Developed a system using Entity Beans to implement abstract object models based on a DSL.
  • Built an eCommerce back office to manage book retail logistics from receiving orders to sourcing from the suppliers through to shipping to the customer.
Technologies: SQL, JBoss, BEA WebLogic Server, JavaScript, Ant, Enterprise Java Beans (EJB), Java

One Kings Lane App for iOS

Since I primarily write web applications for private clients, much of my portfolio is not externally accessible. One recent project, though, can be found in the Apple App Store.

While at One Kings Lane, I was brought in to rescue a retail shopping app for iOS, which was running late and repeatedly missing deadlines.

Immediately, I jumped in, learned Swift, and rewrote the major features, including the product detail page and category navigation.

I worked closely with the product manager and UX designer to clarify and document evolving requirements. I stepped up to make hard decisions on what to keep and what to cut to deliver the project on time.

I introduced and enforced software development best practices to stabilize the project, including tracking all Jira tasks and continuously releasing them to the QA.

Data for the app came from a 3rd-party eCommerce platform. I designed the APIs, documented them in Swagger, and ensured their timely implementation by our partner.

We launched this app in time for the 2018 holiday season, and it has maintained a consistent average rating of 4+ stars ever since.

Toptal React Academy Graduate

The Toptal React Academy is an exclusive learning program that teaches the React framework to select members of the Toptal network. After a month of study, all graduates are tasked with completing a 30-40 hour final project to build and deliver a React app from scratch. The above is a walkthrough of my final project.


JavaScript, SQL, HTML, GraphQL, Ruby, CSS, Pascal, C, Swift, Java, Groovy, TypeScript, C#


MUI (Material UI), Ember.js, QUnit, Ruby on Rails (RoR), Swagger, Express.js, Bootstrap, Ext JS, Hapi.js, Koa, Guice, Grails, Redux, Nuxt.js


React, Node.js, jQuery, Handlebars, SlickGrid, JSON-RPC, XMLHttpRequest, JSON API, Shopify API, Vue, Highcharts, MathJax, NW.js, Reactor, Redux Form


Sequelize, WebStorm, Clubhouse, Jira, Postman, Balsamiq Mockups, Jenkins, Adobe Photoshop, BigQuery, Solr, CasperJS, XDoclet, Adobe ColdFusion, Microsoft Access, JavaCC, Apache Maven, Grafana, Bitbucket




MacOS, Google Cloud Platform (GCP), Docker, Google App Engine, Oracle, iOS, Salesforce, Android, JBoss


PostgreSQL, MongoDB


React Hooks, Ajax, Ant, Spanish, Full-stack, Front-end, Algorithms, React Testing Library, GitHub Actions, Google Cloud Build, Grommet, Compilers, Gantt Charts, Server Sent Events (SSE), Service Workers, Gatsby, PayPal, BEA WebLogic Server, Enterprise Java Beans (EJB), React Spectrum, changesets, Monorepos, BNF, Nearley, Game Development

1994 - 1998

Bachelor's Degree in Computer Science and Spanish

Ohio Wesleyan University - Delaware, OH, United States


React Academy Graduate

Toptal, LLC