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Cole Oliver Cofer

Senior Software Engineer & Tech Lead · Portland, OR

Summary

Senior Software Engineer and Tech Lead with eight years of experience building backend systems in Go, Java, PostgreSQL, Kafka, and Kubernetes. Leads a team of five on the trade booking platform at Apex, a clearing firm with $200B+ in assets under custody, and led its multiyear rewrite from a legacy Java stack into real-time Go services. Early and heavy adopter of agentic AI development who has made it part of how the team designs, ships, and recovers. Outside of work, builds and ships software end to end for the joy of it, including a Steam game and several iOS and watchOS apps.

Experience

Apex Fintech SolutionsPortland, OR · March 2020 – Present
Senior Software Engineer & Tech Lead (Sept 2024 – Present) · SE II (Oct 2021 – Sept 2024) · SE I (Mar 2020 – Oct 2021)
  • Trade Booking Rewrite: Led the multiyear replacement of the legacy on-prem trade booking system (Java, RabbitMQ, MongoDB) with real-time Go, PostgreSQL, Kafka, and gRPC services in the customer trading path, cutting trade confirmation from minutes or hours to milliseconds. Owned architecture and API design throughout. The new platform holds $1B+ in custody, serves 4 million+ requests a day as traffic migrates off the legacy system, and meets FINRA, SEC, and SOC requirements for data retention, PII, multi-region disaster recovery, and daily reconciliation reporting.
  • Scalability Initiative: Drove a cross-team scalability initiative for Apex's clearing platform and owned our team's part end to end: raised booking throughput 25x (200 to 5,000+ trades/second) and cut response times 40% through PostgreSQL query optimization, read replicas, parallelized downstream calls, and async processing.
  • Agentic Development: Established the team's agentic development workflow and used it to reach feature parity with the legacy platform: ported a COBOL library to native Go, wrote end-to-end tests that run daily against live environments, and built a harness that submits trades through both systems and diffs the results. Maintain custom Claude Code skills, restructured service docs so agents can read them directly, and keep teammates current on the tooling.
  • Technical Leadership & Mentorship: Lead a team of five and serve as the go-to engineer for systems handling 20 million+ requests a day, owning API design, architecture, and on-call coordination while still shipping code. Mentor interns and junior engineers through hands-on pairing, several of whom have since grown into senior engineers.
  • Incident Tooling: Built tooling that generates correction files for mis-booked trades and made it self-service for the operations team, replacing hand-built CSVs and one-off scripts, cutting incident recovery time 50%, and giving engineers back hours every week.
InComm Digital SolutionsPortland, OR · June 2018 – March 2020
Software Engineer Intern (2019 – 2020) · QA Engineer Intern (2018 – 2019)
  • Developed and maintained backend microservices for an e-commerce platform using C# and .NET.
  • Built comprehensive automated test suites using Cypress and AVA, improving deployment confidence.

Independent Projects

A mix of hand-written and agent-built work. Radish and Beardsman's Bakery were built entirely with coding agents using a spec-first workflow: detailed upfront design, autonomous implementation and review agents, then heavy testing. More at colecofer.com.

SonaSteam · late 2026 Precision platformer about a bat who navigates by echolocation, built almost entirely solo in Godot 4 with two friends contributing art and music. Grew from a 30-day Game Off 2025 jam entry into a full release with speedrun modes, Steam achievements, and eight languages.
RadishiOS + watchOS · App Store 2026 One-time-purchase calorie and macro tracker with a 700,000-item offline food database, barcode and label scanning, Siri voice logging, and an Apple Watch companion.
Beardsman's BakeryWeb · live since 2025 Ordering site for a friend's home bakery with live stock, first-come pickup slots, and an admin panel. React front end backed by a Google Sheet via Apps Script, with no server or monthly cost.
Brew: Coffee CalculatorApple Watch · App Store 2022 Published watchOS app for dialing in coffee ratios from your wrist without touching your phone.

Education

Portland State UniversityPortland, OR · 2015 – 2019
B.S. in Computer Science

Skills

Proficient withGo, Java, Kubernetes, Kafka, gRPC, PostgreSQL, BigQuery, Docker, Terraform, GCP, Python, Swift, Datadog, Bazel, Claude Code, Codex Familiar withRedis, C#, C++, C, JavaScript, GDScript (Godot), Objective-C, Rust

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Page 1 of 1

Hi, I'm Cole.

I'm a senior software engineer at Apex Fintech Solutions, where I lead a team of five on our core clearing platform, mostly in Go, Java, PostgreSQL, Kafka, and Kubernetes. I've been programming professionally since 2018, and unprofessionally since 2013, when I released my first coffee-brewing app on the Windows Phone Store (RIP Windows Phone).

More than anything, I love to build things. Right now that means Sona, a precision platformer coming to Steam; Radish, a calorie and macro tracker built to run with no servers, so it never needs a subscription, now out on the App Store; and Reach, a paddling tracker for Apple Watch that I started after taking up paddling and balking at the price of a SpeedCoach. Give me a free evening and I will probably spend it making something.

I live in Portland, Oregon, with my wife Christina, our dog Theo, and our cat Lupita. When I'm away from the computer I'm usually outside on my bike, on the water, or fishing, and at home I'm sewing, woodworking, playing guitar, or collecting hobbies — bird watching is the latest.

I'm at my best working on interesting problems with kind, creative people. I'm a backend engineer at heart, but I like the whole stack and I'm happy working anywhere in it. Building software for the outdoors would be the dream.

Sona Steam · planned late 2026

A hardcore precision platformer about a bat who can't fly yet.

I have been making little games since I started coding. After burning out on my dream project, a fly fishing RPG, I took a break and joined Game Off 2025, a month-long jam with the theme "waves." Sona came out of that month, and I've kept building it ever since, now under the studio name C'mon Betsy.

It is a punishing precision platformer, heavily inspired by the classics like Super Mario Brothers 3. Orphaned before she could learn to fly, Sona is searching a sprawling network of caves for other bats to call family. She sees by echolocation, which costs energy, so you eat bugs to keep the lights on and dodge predators in the dark between pulses.

Godot 4.5GDScriptSteamworksPixel art & music, all original4-person team8 languages
Sona Steam capsule art
Animated clip of Sona flying through a dark cave level, echolocation lighting up stalactites and a diamond below Animated clip of Sona hopping between crumbling ledges over lava
  • Hand-crafted levels with midway checkpoints and diamond challenges.
  • Echolocation as a resource: light costs energy, bugs restore it.
  • Simple inputs: run, jump, flap, echolocate.
  • Multiple difficulty modes, speedrun timers, Steam achievements and cloud saves.

This is the original 30-day build, our Game Off 2025 entry, playable right here. The Steam release has changed a lot since then: new levels, new mechanics, new art, and roughly a year of polish. Consider this the baby photo.

Runs right here in the window. About 90 MB, so give it a moment. Click the game once to give it keyboard focus.

WASD / ArrowsMoveSpaceJump
ShiftRunEEcholocate
Open on itch.io

Beardsman's Bakery Live · 2025

An ordering and inventory site for a friend's weekend pastry business.

An online storefront and inventory system I built for a friend so he could grow his weekend pastry business. Brent bakes kouign-amann, cinnamon rolls, and cookies out of his kitchen in Belvedere Tiburon, and he was taking every order by text. That stops working somewhere around a dozen customers, so the site took over the menu, the stock counts, and the pickup schedule.

Loads beardsmanbakery.com inside this window. It's the real shop, so everything works.

  • Custom inventory. Every bake has a quantity for the day, and it counts down as orders come in. Once an item hits zero the menu marks it sold out and stops accepting it. Cancel an order and the stock goes back on the menu automatically.
  • Pickup slots at set intervals. Customers pick a day and a time; once a slot is taken it disappears for everyone else. No two people at the door at once.
  • No payment plumbing. Cash or Venmo at pickup. There is no card processor to onboard, no fees, and no PCI surface.
  • A baker's admin panel. This gives Brent full control over the baked goods, inventory, photos, prices, and pickup windows. It also shows him which pastries are selling and which aren't.

All of it runs on free services. A Google Sheet is the database, an Apps Script web app is the API — it writes each order into the sheet and emails Brent the moment one lands — and the React front end is static files on Netlify. Apps Script is slow enough that you notice it; a request takes a second or two to come back. For a shop selling a few dozen pastries a weekend that is a fine trade: nothing to run, nothing to pay for, and every order lands in a spreadsheet he can sort.

ReactViteTailwindGoogle Apps ScriptGoogle SheetsNetlify

Reach iOS + watchOS · in development

The reach is the forward extension at the catch — where every stroke begins.

The SpeedCoach is the default way to get real analytics on the water and it's genuinely good at it. The catch is $500 for a dedicated piece of hardware. Reach puts the same numbers on a watch you already wear: stroke rate, stroke count, distance per stroke, pace per 500m, splits, and heart rate. You get them live while you paddle and again in the breakdown afterward.

Then it adds the part the hardware doesn't — navigation. Your GPS track draws on the watch as you paddle, so you can find your way around the water instead of only measuring how fast you crossed it.

  • A map on your wrist. Built-in GPS with your route live on the watch face. No phone in a dry bag, no second device.
  • Stroke detection on device. Cadence comes from the watch's motion sensors — no paddle-mounted pod to buy, mount, or charge.
  • Watch-first. Start, track, and end the workout on your wrist with water lock on. Big numbers, high contrast, one-second glances.
  • HealthKit-native. Workouts save as real HKWorkouts with routes, so they show up in Fitness and count toward your rings.
  • No accounts, no server. Data lives on your devices and syncs watch-to-phone directly. Pay once.
SwiftSwiftUIwatchOSHealthKitCore MotionCore LocationWatchConnectivity

It covers dragon boat, SUP, outrigger canoe, kayak, canoe, and rowing. Reach is the app I wished existed when I took up paddling and saw what the hardware cost — it's in active development and headed for the App Store.

Brew: Coffee Calculator App Store · 2022

Coffee ratios on your wrist.

A free little app I made for my wife. She kept asking me how much coffee and water to use, and wanted an easy way to work out the ratio herself. So I built one for her watch: pick a ratio, enter your coffee or your water, and it gives you the other number. It also includes a timer to keep track of your extraction.

It shipped in 2022 and quietly keeps getting used, which is my favorite kind of software.

SwiftSwiftUIwatchOS

Type a number into either box and the other one follows. The slider sets the ratio — one gram of coffee to that many grams of water — and the cup tells you how strong it lands. Everything is grams; a kitchen scale is the only tool you need.

Ratio Calculator — grams, either direction
g
1:16
g
Balanced

We Out Here YouTube · live

Fishing, bikepacking, and whatever else we talk each other into.

I've been making silly videos for a long time. Sometimes I like to make outdoor / fishing / cycling videos with my friends and post them here — feel free to check it out!

The Coast and Back — Bikepack Fishing, Portland to Tillamook

youtube.com/@weouthere9353
Draw something, or let the Muse start it for you.
Left click paints with the primary color. Right click paints with the secondary color.640 x 400
Left click clears. Right click flags.

Get in touch

I'm open to senior backend and platform roles, and I have a soft spot for developer tooling. Email is best.

BaristaBud.xapMy first published app: coffee-to-water ratios, unit conversion, and a brew timer. Windows Phone, August 30, 2013. The store closed; the idea came back nine years later as Brew.2013
AI_Tower_DefenseA tower defense game whose enemies learn how to get past your towers. Python, built for an artificial intelligence course at Portland State.2019
Latte_Art_AnalyzerAn iPhone app that scores latte art using computer vision. Swift, built for a computer vision course.2019
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