Peter Marreck Resume 2026

pmarreck_resume.md

Peter R. Marreck

Port Washington, NY 11050 | 203.570.4096 | peter@marreck.com | LinkedIn: linkedin.com/in/petermarreck | Github

Engineering leader and software architect with 25+ years of experience building financial systems, web platforms, developer tooling, and AI-assisted software. Deep expertise in Elixir, Ruby, PostgreSQL, distributed systems, AI-assisted software development, deterministic development environments, and correctness-focused engineering. Known for solving difficult technical problems, mentoring engineers, creating useful developer tooling, improving measurable performance, and building reliable, maintainable systems.

Education

Cornell University, Ithaca, New York
B.A. in Psychology, Minor in Computer Science

Certifications

• Stanford University Online: Machine Learning (taught by Andrew Ng)
  Certificate: Coursera Certificate
  Date of completion: 4/17/2016

Military Experience

U.S. Air Force, Vacaville, CA
KC-10A Aircraft Electrical/Environmental Systems Specialist (AFSC 2A6X6)

• Troubleshot, repaired, and maintained electrical and environmental systems on KC-10A cargo and refueling aircraft.
• Trained and managed teams of electricians, focusing on safe removal and replacement of high-voltage avionics systems components (awarded ribbon).
• Maintained "secret" clearance level; honorably discharged.
  Form DD-214 separation documentation available upon request

Work Experience

June 2024 - current
Independent Software Engineer / AI Systems Consultant

• Built cross-platform desktop software with pure Zig cores using hexagonal design principles, focused on data integrity and deterministic validation.
• Developed multiple open-source Zig projects exploring LLM-assisted coding, verification, and reliability.
• Ported the legal citation engine eyecite to Zig as incitez, achieving approximately 50x faster execution while improving citation retrieval accuracy by roughly 10%.
• Built a 100% in-browser proof-of-concept demo for incitez.
• Developed MFIC (Mechanically-Falsifiable Independent Controls), a reliability pattern for constraining and verifying LLM-generated work.
• Consulted with attorneys on safe, low-risk use of AI tools such as Harvey.AI in legal workflows.
• Contributed improvements to multiple open-source libraries.

June 2023 - June 2024: Addigence.com, New York, NY
First engineering hire — Director of Engineering

• As first engineering hire, led the technical relaunch on the Elixir/Phoenix/Postgres stack after the original project (built on Dart/Flutter by an offshore team) failed.
• Designed and soft-launched a financial-services site for a trade-action-mirrored portfolio management marketplace.
• Designed and built core features such as auth, Postgres database schema, portfolio tracking, rebalancing, and more.
• Focused on long-term code maintainability and suite/site performance while taking sensible design risks (e.g., use of UUIDv7 for identifiers, zxcvbn for password strength evaluation).
• Conducted code reviews with a focus on best-compromise design decisions.
• Recruited, vetted, hired, and mentored 4 Elixir developers.
• Evaluated managed PostgreSQL providers to reduce operational burden and DBA dependency.
• Utilized Nix to standardize developer environments with minimal ramp-up time, and explored its use for more efficient and deterministic deployments.
• Represented the company at the NAAIM portfolio-manager conference.

Apr. 2017 - Mar. 2024: MPWrealestateboard.network, Manhasset, NY
Solo Full-Stack Elixir Developer

• Developed and launched a real-estate listing project to approximately 800 users.
• Implemented multiple features, including image rotation, full-text search, and roles/permissions enforcement, while maintaining good test coverage and suite performance.
• Managed hosting on Google Cloud/Google Cloud Postgres via Gigalixir, with Travis-CI for continuous integration.
• Open-source code repository: mpnetwork on Github

Sept. 2014 - Mar. 2017: Entrepreneurship & Elixir Experimentation, Port Washington, NY

• Early investor in Bitcoin (largely exited in 2014) and made several startup angel investments.
• Served as a technical advisor for startups including foldapp.com and listenloop.com, and worked briefly with the boost.vc incubator.
• Explored the Elixir language to address long-term maintenance challenges in monolithic Rails web apps.
• Attended multiple ElixirConfs, Empex conferences, and meetups.
• Managed various investment projects and mentored their teams.

Mar. 2014 - Aug. 2014: Kepler Group/43 Bytes, New York, NY
Software Developer/DBA

• Developed background jobs for ETL processes, ensuring data anonymization for PII compliance.
• Optimized data extraction for performance and reliability.
• Implemented a test suite and alert system for data discrepancies.

Feb. 2012 - Mar. 2014: Desk.com ("A Salesforce.com Company"), Melville, NY
Senior Ruby on Rails Developer

• Contributed to a million+ lines of code Rails codebase, mentoring team members.
• Resolved a deep lost-session bug affecting thousands of customers that at least 6 other developers had failed to find.
• Reduced the test suite run time by 33% and established code quality standards.
• Optimized email header parser code, resulting in a 250x speed increase using a well-commented Regex and thorough test suite.
• Promoted to the internal "Platform" team responsible for codebase integrity and tooling.

Aug. 2011 - Dec. 2011: Lifebooker.com, Brooklyn, NY
Senior Software Developer

• Built features in Ruby on Rails, jQuery, and CoffeeScript; mentored new hires.

Sep. 2009 - May 2011: ThredUP, Inc., San Francisco, CA (remote; onsite in Cambridge, MA)
First employee — Website Architect / Ruby on Rails Lead Developer

• Joined as the first employee and built thredUP.com from the ground up; site grew to 100,000 active users and the company IPO'd in 2021.
• Designed the database schema, built the recommendation engine, upgraded the codebase to Ruby 1.9/Rails 3, and deployed to Amazon EC2/S3/RDS with USPS API integration for live postage labels.

Sep. 2006 - Dec. 2008: Keane, Inc., Cambridge, MA
Principal Consultant/Web Developer

• Rebuilt production sites (e.g., statestreet.com, bostonpublicschools.org) using Ruby on Rails.

May 2006 - Aug. 2006: Helium.com, Andover, MA
Rails Software Developer (Contract)

• Translated functional requirements into tested Rails code with a MySQL backend.

Nov. 2003 - Mar. 2006: Deloitte and Touche (Capital Markets/ERS Architecture Group), Boston, MA
Senior Consultant

• Built and supported the "Risk Control Tracking System" (RCTS) Sarbanes-Oxley compliance application: complex SQL-backed reports rendered via XSL, scripted data imports and migrations, automated test coverage, and internationalized date/time handling.

Jan. 2000 - Aug. 2003: FactSet Research Systems, Greenwich, CT
Junior Software Developer

• Designed and implemented a SQL-driven financial data discrepancy email notification application ("Broadcast") with a web interface; built ETL of application usage data into SQL Server and led a pair-programming project to synchronize Lotus Notes customer data with Onyx CRM.

Technical Skills

• Languages: Elixir, Ruby, Zig, SQL, Bash, JavaScript, Lua, HTML, CSS

• Frameworks & Platforms: Phoenix, Ruby on Rails, PostgreSQL, AWS, Google Cloud, Docker, CI/CD

• Tools & Methods: Git, jujutsu (jj), Nix, Linux, macOS, ETL, automated testing, performance optimization, LLM-assisted development

• Human Languages: Proficient in German; conversational in Spanish and French.