Sébastien Armand
Principal Software Engineer

Info

Experience

PDF Version

Sébastien Armand
Principal Software Engineer

Square | Principal Engineer - Product Engineering
USA | June 2018 - Present

2024 - now | Principal Engineer - Product Engineering

One of 3 principal engineers in Square's product engineering team (over 300 engineers)
  • Organized an "unconference" for Square Engineering, brining together 50 of our most tenured engineers together to address our most pressing issues
  • Restarted a long dormant project of migrating Square Online to a common AWS platform with the rest of the company
  • Contracted external agency to gradually take over the maintenance of legacy Weebly product and customers
  • Prototyped a new reporting platform now being evaluated for company wide adoption

2022 - 2023 | Tech Lead - Square Online

Tech Lead for all of Square Online's product engineering team (100 engineers)
  • Transition all (billions) static assets to be served via CDN, drastically improving online store load times for customers all over the world
  • Transition core commerce APIs to be cached via CDN and use surrogate keys and tagging to ensure no stale data
  • Prototyped and spearheaded the adoption of envoy as a service to service proxy, reducing S2S call latencies p95 by 60ms
  • Proposed and initiated project to finalize the Weebly merger by moving all Online solutions to use Square data as a primary source

2018 - 2021 | Tech Lead - Online Store Operations

Tech lead for Square Online's store operation team while we worked on:
  • Ongoing microservice migration, moving large functionality away from pre-existing monolith
  • Shipping integration. Close partnership with UPS as a preferred partner for shipping orders.
  • Fulfillment updates, with the addition of scheduled orders, timed menus, delivery partners (doordash, uber eats)
  • Period of hypergrowth and scale during the pandemic, growing 10x in a few months
  • Designed and developed advanced caching strategies for APIs essential to our handling of sudden growth
  • Proposed, designed and developed a re-architecting of catalog data from MySQL to ElasticSearch, bringing end user latencies p95 down from 20s to 500ms, 40x improvement
  • Designed adaptive algorithms that help our systems handle unexpected load in live and async workloads

Weebly (acquired by Square) | Software Engineer
USA | May 2017 - June 2018

Weebly is a website builder and hosting service. I worked on the team responsible for all e-commerce features of the platform.
  • Product Reviews: this was the first project deployed in production on Kuberenetes. Also the first microservice broken up from the monolith, setting up the path for how we did microservices.
  • Setup the main e-commerce API service for the platform. Still to date the largest of those with thousands of tests, hunreds of contributors, tens of thousands of merged PRs. The early approach, design and leadership were crucial to the long term success of the project.
  • Square Catalog compatibility. One of the projects that helped realize the merger between Square and Weebly.

Creative Market (Autodesk) | Platform Software Engineer
USA | November 2014 - May 2017

Maintain and grow a digital goods marketplace serving over 3 million users. Some major features I worked on were:
  • Real time sales dashboard for shop owners
  • Shop Updates: a dynamic social feed enabling shop owners to share news about their new and existing products
  • Loyalty Program
  • Auto-download of purchases to Dropbox
  • Purchase search allowing buyers to search and filter through their past purchases
  • Support for markdown, video, 3D support to product pages and many customizations to each seller's main shop page.
  • Updates to our open API platform for partners
Beyond the projects, I also contributed in other forms to the company:
  • Main driver for having automated tests on the main application
  • Identifying and resolving high risk application security issues
  • Working closely with the support team, ensuring quick responses and a good experience for our customers
  • Build and maintain the company's largest search index with real time updates
  • Prepared, tested and ran our largest database migrations
Skills PHP, MySQL, SQL Schema and Query optimization, Elasticsearch, Memcached, jQuery, Backbone.js, React.js, Continuous Integration, Unit Testing, Caching strategies, Performance profiling and tuning, DevOps

CRM Factory | Lead Frontend Engineer
CHINA | July 2012 - September 2014

Develop highly dynamic and customizable JavaScript / HTML5 single page & mobile applications including
  • FairGarage: a car workshop search engine and booking system that had 20,000 listed workshops around Germany in 2014. Rebuilt frontend to allow quick iteration and experimentation of customer preferences.
  • MySales / MyService: a suite of tablet applications for car manufacturers and their dealers to follow the sales and maintenance processes. Built on a modular architecture to allow for quick customization and deployment for different manufacturers.
  • Berlin Film Festival: Frontend for internal scheduling system managing the screening of hundreds of movies in dozens of cinemas in one, cohesive, dynamic view.
  • Rent 2.0: Single page, responsive JavaScript & HTML5 application for automated car rentals. Single code base for all client devices (desktop, tablet, mobile with hybrid web/native apps).
  • Timebooker: internal project for booking and tracking employee time per project.
  • Transparo: Insurance price comparator developed in JS that could be dropped and embedded into any website.
Beyond my impact on the projects, I had a large impact on team / company operations as well:
  • Set up a regular learning and sharing program for the development team including bi-weekly tech talks
  • Setup the AngularJS Beijing meetup at the company office
  • Drove adoption of bitbucket (git) and practicing code reviews
  • Overhauled hiring screening of developers to a set of standard, vetted, interview questions
  • Overhauled hiring screening to a set of standard, vetted, interview questions
  • Moved unit testing to become a mandatory practice
  • Enabled the adoption of CI automated tests for frontend apps
Skills technical leadership, SCRUM / Kanban agile methods, continuous integration and delivery, unit testing, TDD, automation, CI/CD, Git, SVN, Javascript, a lot of now defunct JS tools

Mashup | CTO - Co-Founder
CHINA | April 2012 - April 2013

Create a sports oriented social network that lets users organize and take part in sport and social activities.
  • Concept creation, Design and UI implementation
  • Full implementation of the backend
  • Used by many activity organizers and has hundreds of users who played thousands of games.
  • Launched the initial platform with a 2 people team.
  • Startup Leadership Program fellow
Skills symfony 2, MongoDB, software design, software archintecture, continuous integration, testing, server management, investor pitch, business plan

JCDecaux | Product Manager & Lead Developer
CHINA | April 2009 - July 2011

Build and deploy a highly flexible IT system for sales management across multiple countries in Asia (China, Singapore, India, Japan).
  • Help the existing team move to standard methods tools and processes (version control, unit testing, planning etc...)
  • Ensure the delivered quality at all levels
  • Plan and manage full re-write of the existing system leading a 6 people team over 6 months
  • Train local team on new technologies (adopting symfony framework)
  • Ensure maintenance of the existing system in countries where it was already deployed
  • Configure and deploy the new system in other countries within the group
Skills team management, self organization, challenge people’s needs, systems architecture, Symfony PHP framework, MySQL, PHP

Ecole Centrale Lyon | Master in Engineering
FRANCE | September 2004 - November 2008

The Ecole Centrale de Lyon is a top 10 engineering school in France.

Third year specialization in Information Technology & Supply Chain Management.

Gap year in 2006 / 2007 split between two internships including my first opportunity to come to China.

Internships and study projects:
  • 2008: configure and prepare deployment of an ERP system for Dalkia (heating & cooling management company).
  • 2007: participate in an initiative to standardize mobile operating systems for Orange. This initiative is now part of LiMo (Linux Mobile Foundation)
  • 2006: implementation and study on CRM (customer relationship management) softwares.
  • 2006: network simulation and performance test for a new service discovery protocol for a research team, resulting in the publication of their research paper .
  • 2004: study project on creating a portable cancer detection system for general practitioners. Assemply programming of the PIC microcontroller at the heart of the system.