Hi, I'm

James MacWilliam

Senior Rails Engineer & Software Architect

10+ years shipping production Rails systems. Strong IC. Comfortable leading. Quality-focused and intentional.

Green Cove Springs, FL
Get in touchView my work

01. About

A bit about me

I'm a senior Ruby on Rails engineer and software architect with over a decade of experience designing and shipping production systems — from greenfield builds to complex integrations at scale. I'm equally comfortable operating as a hands-on individual contributor or leading architecture and mentoring across a team. I continuously experiment with new technology while applying it pragmatically. What that means practically is that I'm regularly spiking on new ideas that will move the needle for clients, while also striking a balance between Claude Code usage and carefully interrogating and reviewing the quality of both the code and the overall user experience.

02. Experience

Where I've worked

Jun 2025 – Present

Remote

Senior Software Engineer @ Abbove

  • ▸Built a version 2 banking API, including a new Flanks banking/investment data integration.
  • ▸Built a customer-facing MCP server, exposing Abbove platform capabilities to AI agents and LLM-powered client workflows.
  • ▸Partnered with the infrastructure team to move report generation to an AWS Lambda-based pipeline, improving reliability and cost.
  • ▸Remediated findings from internal and external penetration tests across the API surface.
  • ▸Served as primary technical point of contact for client-facing communication on API and Flanks integration work.
Ruby on RailsNode.jsPythonTailwind CSSTurbo/HotwireMCPAWS ECSLambdaTerraformPostgreSQL

Oct 2023 – Jun 2026

Remote

Lead Engineer (Contractor) @ Skillit

  • ▸Built an agentic AI interviewer using SMS and Twilio to schedule, connect, transcribe, and extract insights from candidate interviews.
  • ▸Prototyped a voice-based version with a reusable Go service handling text-to-speech/video conversion against Rails backend output.
  • ▸Owned the Elasticsearch/OpenSearch layer, including filters, boosts, aggregations, and embedded/vector search.
  • ▸Built the billing system and Stripe integration.
  • ▸Designed inbound call routing logic to conditionally connect calls to conferences, create new ones, or route to customer service.
Ruby on RailsGoElasticsearch/OpenSearchTwilioStripeAWS ECSOIDCPython

Apr 2020 – Jun 2023

Remote

Chief Technology Officer @ Big Southern Software / Live Oak Computer Science

  • ▸Led design and development of a Learning Management System teaching coding skills to middle and high school students.
  • ▸Engineered IoT components to capture and analyze image data, integrated with the core software platform.
  • ▸Owned hiring, 1:1s, product roadmap, and technical mentorship via a lunch-and-learn program.
  • ▸Delivered a tailored management application supporting sister-company operations across multiple industry verticals.
Ruby on RailsReactReduxTailwind CSSPostgreSQLPythonOpenCVC++

Oct 2016 – Apr 2020

Remote

Senior Software Engineer @ Spreemo / One Call Care Management

  • ▸Integrated with Bill.com and QuickBooks to automate accounts receivable/payable.
  • ▸Implemented SAML single sign-on and built claim search and combined-claims workflow features.
  • ▸Optimized query performance and caching, improving performance across the application.
  • ▸Automated faxing workflows and PDF generation to streamline collaboration with medical providers.
Ruby on RailsMySQLSAML SSOBill.comQuickBooksChefPython

Mar 2015 – Oct 2016

Remote

Senior Software Engineer / Team Lead @ PhishMe, Inc. (now Cofense)

  • ▸Led an engineering team: hiring, 1:1s, and project planning.
  • ▸Rebuilt the reporter tracking system for phishing-email reports and associated statistics.
  • ▸Used Percona toolkit for zero-downtime schema migrations on large tables.
  • ▸Migrated authorization to Pundit and shipped multi-company account support and a small-business product offering.
Ruby on Rails 4SidekiqRedisCapistranoPercona Toolkit

Nov 2011 – Present (ongoing, part-time)

Remote

Staff Engineer (Contractor) @ LIMSey

  • ▸Replaced SOLR with a performance-tuned PostgreSQL search implementation.
  • ▸Built advanced search, saved-search, and grid-based sample and task/result management features.
  • ▸Implemented SAML single sign-on and streamlined calendar/task scheduling workflows.
  • ▸Advise on architecture and best practices in customer-facing design sessions.
Ruby on RailsPostgreSQLSAML SSORedisTailwind CSS

03. Work

Selected work

Sam by the Numbers analytics dashboard

Skillit

Lead Engineer

Skillit connects construction companies with skilled workers. I led engineering across the platform — owning the Elasticsearch/OpenSearch search layer, billing and Stripe integration, and the product's most ambitious feature: Sam, an agentic AI interviewer that schedules, conducts, transcribes, and extracts insights from candidate interviews entirely over SMS.

Sam by the Numbers — 4,358 messages, 184 interviews, 138 calls driven autonomously since launch

Abbove API v2 OAS 3.0 documentation

Abbove

Senior Software Engineer

Abbove is a wealthtech platform for estate planning professionals. I built the second-generation banking API from scratch — an OAS 3.0 spec powering a new Flanks banking/investment data integration — and led the effort to move report generation to a Lambda-based pipeline, reducing cost and improving reliability. I also built a customer-facing MCP server, exposing Abbove platform capabilities to AI agents and LLM-powered client workflows.

Abbove API v2 — OAS 3.0 spec built from scratch, including health, auth, banking, and investment endpoints

Point to Point Hub job workflow tracker

Point to Point Hub

Software Architect (The Pesto Group)

A project management and workflow platform for land survey companies. I architected and built the job lifecycle tracker — covering every stage from intake through title research and final delivery — a searchable web Field Code Finder giving surveyors instant access to 414 standardized field codes with CSV, PDF, and FCL export, and a companion React Native mobile app bringing the same field code reference to surveyors in the field.

Job workflow — multi-stage lifecycle tracker from receipt through drafting and delivery

04. Projects

Things I've built

percona_ar

A pt-online-schema-change DSL for high-performance ActiveRecord/MySQL migrations — zero-downtime schema changes on large production tables.

RubyActiveRecordMySQLPercona Toolkit

active_record_uniqueness_via_db

Faster uniqueness validations using DB index constraints, eliminating race conditions on concurrent inserts that ActiveRecord's built-in validates_uniqueness_of can't prevent.

RubyActiveRecordPostgreSQL

bcrypt_hmac

Contributor. Adds HMAC pre-hashing to bcrypt, enabling secure password hashing for inputs that exceed bcrypt's 72-byte limit without silently truncating credentials.

RubybcryptSecurity

skillit-eng

Authored the majority of the open source tooling in the Skillit engineering GitHub org — search infrastructure, agentic interview tooling, and platform utilities built during my time as lead engineer.

Ruby on RailsGoElasticsearchTwilio

05. Skills

What I work with

Backend

  • Ruby on Rails
  • Node.js
  • Go
  • Python
  • Elixir
  • Sidekiq / SolidQueue

Frontend

  • React / Redux
  • TypeScript
  • Turbo / Hotwire
  • Tailwind CSS
  • Stimulus
  • View Components

Data

  • PostgreSQL
  • MySQL
  • Redis
  • Elasticsearch / OpenSearch
  • MongoDB
  • SQL Server

Infrastructure & AI

  • AWS (ECS, Lambda, S3, RDS)
  • Docker
  • Terraform
  • RAG / Vector Search
  • Agent Orchestration
  • CI/CD

06. Contact

Get in touch

Whether you're looking to hire, collaborate, or just say hello — my inbox is open.

Say hello