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Bill Kohler

Software Engineer in Boston, MA

Projects

hihat

hihat.online

An operating system for the live-music business.

The routing calendar for the artist 100 Gecs, showing a July 2026 month grid with a confirmed $18,000 date at the Ogden Theatre in Denver and a pencilled hold at The Van Buren in Phoenix.
  • The promoter demand-signals discovery board, listing emerging artists as cards with an opportunity score, a weighted signal bar, a 60-day demand trend line, and Interested or Pass actions.
  • A signal detail panel for the band American Football, showing a suggested guarantee range of $1,000–$2,000, a 60-day demand index chart, and a radar plot breaking the opportunity score into ticket intent, velocity, live performance, web buzz, and sync demand.

A Phoenix LiveView platform for the live-music industry. It ingests offers and deal-memo PDFs, pulls tour routing from Ticketmaster and Bandsintown, scores promoter demand signals, and runs fan-facing storefronts — the tooling I wished existed when I was booking shows.

  • Offer and deal-memo PDF ingestion with structured extraction, turning unstructured contracts into queryable deal terms.
  • Tour-date aggregation across the Ticketmaster and Bandsintown APIs.
  • Promoter demand-signal scoring to rank markets and routing options.
  • Hold optimizer for resolving competing venue holds on the same date.
  • Fan commerce and artist storefronts.
  • Elixir
  • Phoenix
  • LiveView
  • Oban
  • PostgreSQL
  • Fly.io
Private source

spinbook

A betting engine for Beyblade.

The spinbook match list, showing live Beyblade X matchups with each player's three-blade lineup and the ratchet and bit combination for every blade.
  • A live spinbook match between Bird and Keel, with round-by-round versus banners and three betting markets — Outcome, Technical, and Chaos — offering wagers on the round winner, first X-Dash scorer, match duration, and a double burst, each showing as locked while awaiting a result.
  • The spinbook leaderboard — a frosted-glass podium ranking the top three bettors by BeyCoin balance, above a list of remaining ranks.

A real-time wagering app built to push OTP where it is strongest. Each match runs its own GenServer bookie process, recalculating odds as bets land and broadcasting them over Phoenix PubSub so every connected client stays in sync without a page refresh.

  • Per-match GenServer bookie engine isolating each match's state and betting pool.
  • Live parimutuel odds recalculation broadcast over Phoenix PubSub.
  • Leaderboard with an achievement badge system.
  • Elixir
  • Phoenix
  • LiveView
  • GenServer
  • PubSub
  • Tailwind CSS
Private source

goblin

A Discord bot that turns group chat into a published blog.

The goblin blog timeline — a vertical rail of dated music posts with album and artist thumbnails, styled as a green-on-black CRT flyer.
  • The goblin bot replying in Discord to an /add_to_playlist command, confirming "Song Added to Playlist!" with album art for Nine Inch Nails and Tame Impala, and prompting for a narrower query when a search is ambiguous.
  • The resulting "goblin bot" public playlist in Spotify, illustrated with a green goblin in a blue cap writing on a scroll, listing six tracks by Cher, Nine Inch Nails, Poppy Jean Crawford, Tame Impala, Incubus, and From First To Last.

Friends drop music and film recommendations into a Discord channel; goblin reads the threads, resolves them against Spotify and Letterboxd, and publishes curated lists through a Wagtail CMS. An excuse to work outside the Elixir ecosystem for a while.

  • Ingests and parses Discord threads for shared media links.
  • Resolves links against the Spotify and Letterboxd catalogs.
  • Publishes curated posts through a Wagtail CMS.
  • Python
  • Discord API
  • Django
  • Wagtail
  • Spotify API
Source

hot dogs

... It's basically Tinder for dogs hot dogs for all dogs!

The Hot Dogs iOS app's Discover screen — a dog profile card for Thor, a Boxer, with bone and hot-dog swipe buttons and a Hot Dog Hotness score above.
  • The app's Profile tab, showing a Hot Dog Hotness card reading "Fresh Off The Grill" with progress toward a reward hot dog at 100 likes, above an Add a Dog action and account controls.
  • The Add a Dog sheet, a grouped iOS form collecting the dog's name, breed, age, and a fun fact, with a photo picker requiring at least one image.

An app just for fun — who doesn't love cute dog pictures on the internet. A native SwiftUI card stack where you swipe right with a hot dog emoji and swipe left by throwing a bone, backed by Firebase with a Phoenix service for photo moderation. Built to learn the iOS toolchain end to end.

  • SwiftUI swipe-card stack with match and chat flows, backed by Firestore.
  • Hot-dog and bone swipe actions, with a Hot Dog Hotness score that earns a reward at 100 likes.
  • Phoenix backend service for photo moderation.
  • Swift
  • iOS
  • Firebase
  • Elixir
  • Phoenix
Source

Experience

Youth Inc logo

Youth Inc

Boston, MA

  1. Senior Software Engineer

    • Own the order-fulfillment integration layer end to end — 100% of company order volume, roughly 6,100 orders a year — routing across ShipStation (REST/webhooks), LINX (SOAP), and FulfillEngine with idempotent submission and reconciliation, plus the shipment-tracking pipeline that notifies customers on ship.
    • Led the platform's AWS migration: containerized the Elixir/Phoenix app, stood up a full parallel staging environment on ECS and RDS managed by Terraform with cost controls, and cut traffic over to it. Built a CloudWatch reporter on Oban queue depth to drive ECS auto-scaling under queue pressure.
    • Built the company's observability stack from scratch — structured Slack error alerting with rate-limited grouped threads, PII redaction in production logs, and CloudWatch metrics — surfacing a class of integration failures that had been failing silently.
    • Closed a critical disaster-recovery gap with automated production database backups, taking recovery point objective from unbounded to a fixed window, plus prod-to-local restore tooling that is now the team's standard debugging workflow.
    • Bootstrapped and own the Phoenix LiveView commerce platform used daily by operations — inventory ingestion with dry-run diffs, SKU launch automation, per-decorator fulfillment dashboards, demand forecasting with at-risk SKU detection, and per-SKU margin reporting — replacing SSH-into-production console workflows with self-serve tooling.
    • Designed an automated hold/release system for embroidery orders: orders missing production files are held back from decorators, operations is alerted via Slack, and orders auto-release on file upload — eliminating a class of silently failed orders and the manual resend work around them.
Mastercard logo

Mastercard

Boston, MA

Joined via the SessionM acquisition; promoted twice.

  1. Senior Software Engineer

    • Engineered microservices for the SessionM Loyalty Platform, reliably handling 100M+ daily requests.
    • Served as Ruby Guild Lead, running technical discussions across engineering teams to drive best practices, code quality, and alignment on standards.
    • Cut critical incidents 40% by instrumenting client environments with CloudWatch and SignalFx and tightening the on-call loop.

  2. Software Engineer II

    • Scaled the catalog management system to support substantially larger SKU assortments across client tenants without degrading catalog query performance.
    • Acted as Technical Product Owner — led agile ceremonies and translated between engineering and product to align technical priorities with roadmap goals.
    • Refactored the GraphQL API to enforce per-field access control and close platform security gaps.

  3. Associate Software Solutions Engineer

    • Core member of the engineering SWAT team, diagnosing and resolving high-priority production incidents across client deployments.
The Kurland Agency logo

The Kurland Agency

Boston, MA

  1. Director of Information Technology and Innovation

    • Owned agency-wide technology and internal tooling for a talent agency representing jazz, world, and blues artists.

  2. Associate Agent

    • Negotiated engagements and drafted performance contracts for touring artists.

Education

  • Boston University logo
    Boston University — Certificate in Computer Science2017
  • Northeastern University logo
    Northeastern University — B.S. Music, Minor in Business Administration2013