Javier Julio

• [email protected]
• javierjulio.com
• github.com/javierjulio

Experience

Senior Lead Software Engineer - DraftKings

May 2024 - Present

• Led a cross team security initiative by upgrading ImageMagick from v6 to v7, remediating 30+ critical vulnerabilities and unblocking 3 EOL technologies, enabling a successful, zero downtime Ruby upgrade from 3.0 to 3.4 and reducing Sidekiq memory spikes from 28GB to a stable 16GB.
• Established regression safeguards by implementing ticket scantron image comparison testing, ensuring safe adoption of ImageMagick v7 updates for critical ticket-processing workflow.
• Architected and led migration from Okta to Duo for 300+ employees across Lottery admin and operations systems, consolidating authentication onto DraftKings-standard infrastructure to reduce vendor overhead; maintained uninterrupted fulfillment operations nationwide through zero-downtime rollout.
• Drove containerization efficiency initiatives, reducing Docker image sizes by 80%+ (services) and 50% (monolith), improving security and deployment speed.
• Partnered with leadership to reduce infrastructure and operational costs, decommissioning legacy systems to support company-wide EBITDA targets.
• Defined and implemented observability standards by introducing Datadog SLOs/SLIs for the Lottery Rails backend, improving service reliability, alerting quality, and incident response.

Staff Engineer, Founding Team - Jackpocket

Jun 2014 - May 2024

• Joined founding team and helped scale the company to 200+ employees, culminating in a $750m acquisition by DraftKings.
• Architected and built end-to-end ACH payment and withdrawal infrastructure (with Balanced, Synapse and then Dwolla & Plaid), processing six-figure daily transaction volume per flow.
• Expanded payment capabilities by implementing credit card and Apple Pay flows and leading PayPal and Venmo integrations, increasing user conversion.
• Reduced CI pipeline time from 20 to 4 minutes and test suite from 18 to 2 minutes (1 minute locally) with parallel execution, significantly accelerating engineering velocity.
• Reduced Rails monolith deployment wait time from 45+ to 10 minutes with trunk-based development, parallel tests, and feature flags.
• Implemented organization-wide security and code quality automation workflows (linting, secrets detection, static analysis, typos), improving reliability across 20+ repositories.
• Eliminated insecure GitHub PAT usage with GitHub App-based auth, improving security with short-lived, scoped tokens.
• Led migration of jackpocket.com and designed a decoupled architecture by building blog.jackpocket.com on Zesty CMS, empowering non-engineering teams to fully own content and SEO strategy, significantly accelerating publishing delivery.
• Increased code coverage from 73% to 97%, improving Rails monolith reliability and release confidence.
• Led migration of regulatory reporting pipeline from Rails & Postgres to Google Cloud Functions & BigQuery, enabling generation of large-scale compliance reports in seconds and eliminating failures; improved reliability and ensured on-time delivery for state-mandated deadlines across multiple jurisdictions.
• Core contributor and maintainer of ActiveAdmin since 2017.

Contract - WordLab (Jackpocket)

Sept 2014 - Dec 2014

Created an iOS app in Swift for learning words using flash cards in the Leitner system. Created a Ruby script to parse the public domain Webster dictionary to populate the initial Realm database.

Senior Software Developer - 9mmedia

Apr 2010 - May 2014

• Contributed to FitnessBuilder's iOS 8 rewrite by porting the Metrics feature and rewriting over 50 SQL queries to CoreData.
• Implemented MyFDB redesign with focus on images for content, new onboarding flow and social features: profiles, collecting, following, sharing, infinite scroll feeds, etc. Rails 3.2 app on Heroku using Postgres, AWS, Solr and Redis.
• Increased average MyFDB site duration time to 4 minutes from lowest average of 40 seconds. Decreased bounce rate by 40%.
• Optimized MyFDB pages that had 90+ queries down to 5 or less. Rendering times reduced from 3 seconds to 400ms without caching. Average 500ms app server response time (NewRelic) was cut in half.
• Increased FitnessBuilder conversion rates by syncing user and transaction data to Salesforce then ActOn to create plan specific campaigns to email users throughout their trial.
• Planned, managed, and developed the FitnessBuilder web app using Flex 4.5, Swiz, Ruby on Rails and RubyAMF.
• Developed a Flex 4 and Swiz admin for the FitnessClass iPad app.
• Created and maintained four in house Flex libraries for custom MX, Spark and RPC components.

Developer - Arc90

Sept 2007 - Apr 2010

• Developed Flex modules and custom components using PureMVC for a RESTful insurance policy origination platform that allowed multi-tasking for underwriters to manage the policy lifecycle and agents to track changes.
• Rewrote the Readability bookmarklet content parser to search based on keywords in attributes and to use a scoring system to determine content container from multiple results.
• Developed an insurance policy scoring analysis management app using Flex, PureMVC, ColdFusion and AMF that dynamically created reports in Excel with data retrieved from SQL Server stored procedures.
• Developed Question Picker for McGraw Hill, a cross browser, single page AJAX app with jQuery that used nested categories, dynamic modal windows, and complex addition/removal of questions.

Developer - AboutWeb

Oct 2005 - Sept 2007

• Developed a CMS with template, document and element versioning as a ColdFusion 8, Model Glue app for the NIH.
• Redesigned AboutWeb site from ground up using web standards.
• Developed class management tool for Intelliworks in their ColdFusion based CRM app for Higher Education.
• Enhanced a Model Glue, ColdFusion, Flash form based app for AAO where doctors can submit research papers with peer review.

Developer - Katrina Lost

Sept 2005 - Dec 2005

Developed a ColdFusion app (volunteer project) to help Hurricane Katrina victims find missing relatives and available housing. Built over a weekend. 179,000 visitors on launch day. Used 10GB of bandwidth in 10 days.

Webmaster - ESS

Jun 2005 - Oct 2005

Updated ESS and ESS Expo sites using web standards (source ordering, no tables for layout) and new ASP backends for improved SEO and maintenance.

Web Intern - World Resources Institute

Apr 2004 - Apr 2005

Replaced the site tree navigation with a cross browser, drop down menu. Worked on several ColdFusion apps.

Skills and Technologies

Languages: Ruby, JavaScript, Python, Shell, Elixir, HTML, CSS, Swift, Objective-C, AS3, MXML, REST, JSON, ColdFusion

Frameworks: Rails, React, Svelte, Ember, Realm, Flex, Swiz, PureMVC

Tools: Git, Postgres, Redis, Docker, RabbitMQ, Figma, Sketch

Education

Montgomery College
A.A.S., Web Programming Degree - 3.57 GPA (2001-2005)

• Hispanic Student Achievement Award
• Computer Applications Academic Achievement Award
• Best Final Project Award in Advanced ColdFusion
• Best Final Project Award in ColdFusion

Presentations

• CSS: Cosmetic Content Without The Bloat (2013)
• Building Maintainable Applications with PureMVC (various 2009-2010)
• Using Flex Frameworks to Build Data Driven Applications (2009)
• Building ColdFusion Applications with Framework One (2010)
• Digging Through the Flex Framework (various 2009-2010)

Certifications

• Flex 2: Data & Communications (Adobe Certified Training)
• Flex 2: Developing Rich Client Applications (Adobe Certified Training)