Leonardo Ciappi
Software Engineer

I build reliable backend systems and the occasional multiplayer game. Currently at Remitly, helping move $70B+ a year to families worldwide. Previously at Activision (Call of Duty), Microsoft (Gears of War), and Seaspan. I write the invisible code that makes apps work. Right now I work at Remitly — they help people send money to family in other countries (about $75+ billion every year). Before that I helped make video games like Call of Duty and Gears of War.

See my work LinkedIn GitHub Email
Leonardo Ciappi, Software Engineer at Remitly
// Where I've shipped

Experience

From global payments to AAA game servers — five engineering roles across financial infrastructure, online games, and industrial software. Five companies, from money-sending apps to video games to giant cargo ships.

Remitly
Global Payments
Activision
Call of Duty
Gears of War
Seaspan
Marine Logistics
BREIN
Advanced Analytics
Jul 2025 — Present Remitly

Software Engineer

Go · Java · Kubernetes · Jenkins · Redis

  • Designing, building, and maintaining a global payment network that reliably moves $70B+ annually to families worldwide.
  • I help keep the system running that moves $75+ billion every year — that's people sending paychecks home to their families across the world.
May 2024 — Dec 2024 Activision · Demonware

Software Engineer Intern · Call of Duty

Python · C++ · Kubernetes · Argo CD · Redis

  • Extracted tournament-coordination matchmaking logic into a new standalone Python micro-service.
  • Took the part of Call of Duty that pairs players up for tournaments and split it off into its own little program — easier to fix and faster to update.
  • Wrote an RFC for an updated matchmaking flow projected to deliver a 13% ping improvement for large parties.
  • Designed a smarter way to pair up big groups of friends — they'll feel 13% less lag when playing together.
  • Supported the Black Ops 6 launch for millions of players — preparing deployments and monitoring live performance.
  • Helped launch Call of Duty: Black Ops 6 and watched the servers like a hawk so millions of players could log in on day one.
  • Implemented a dictionary-based caching layer for game-playlist objects, cutting Redis traffic and load times.
  • Made the in-game menus load faster by remembering things instead of asking the server every single time.
Sep 2023 — Dec 2023 Microsoft · The Coalition

Software Engineer Intern · Gears of War

C++ · C · C# · Unreal Engine 5

  • Designed and shipped in-game telemetry tracking player online activity across session states.
  • Built the system that tracks what players are doing inside Gears of War — so the team can spot problems quickly.
  • Added C++ lifetime management to telemetry sources in the Online UE5 plugin.
  • Made sure parts of the game properly clean up after themselves so the game doesn't crash.
  • Built infrastructure to set and test custom retry policies for all requests in the Online UE5 plugin.
  • Built a tool that lets the game automatically try again when the internet gets shaky — and verified it works.
May 2023 — Aug 2023 Seaspan · Business Transformation

Software Engineer Intern

Python · SQL

  • Led a team of 10 interns building a servicing solution for 200+ container ships.
  • Led 10 other interns to build software that keeps 200+ giant cargo ships in good shape.
  • Automated vendor registration via API orchestration, reducing processing time from 28 → 12.3 days.
  • Wrote code that signs up new suppliers automatically — what used to take a month now takes about 12 days.
May 2022 — Oct 2022 BREIN · Center for Advanced Analytics

Software Engineer Intern

React · TypeScript · Node.js · Azure

  • Contributed to a web app projected to generate $700K by digitizing the smelting process at a tin foundry.
  • Helped build a website for a metal factory that's expected to make them an extra $700,000.
  • Deployed on Azure, designed REST APIs connecting front-end to back-end.
  • Put the website online and built the wiring that lets what you see on screen talk to the database.
  • Achieved a 98% improvement in load times by indexing SQL columns and refactoring queries.
  • Made the website 98% faster by reorganizing how it asks the database for stuff.
// Featured project// My favorite project

Liar's Dice — Real-time multiplayer Liar's Dice

A full-stack multiplayer game I designed and built from scratch — Go backend, React/TypeScript frontend, end-to-end real-time over WebSocket. An online dice game I built completely by myself — you make a room, share a code with friends, and play together in real time.

Live · Liar's Dice.ciappi.xyz

Liar's Dice

Server-authoritative Liar's Dice. Create a room, share the join code, and bluff your friends in real time. Liar's Dice — share a code with friends and bluff your way to victory. The computer keeps everyone honest.

  • Designed the system end-to-end — concurrency model, WebSocket protocol, game engine, client state machine.
  • Designed every part myself — how the computers talk, the game rules, what the screen looks like.
  • Hub-per-room goroutine pattern in Go — single-writer ownership of game state, no locks on the hot path.
  • Each game room is handled separately — fast and never gets confused, even with lots of games happening at once.
  • Pure-functions game engine isolated from networking — table-driven tests cover every bid/doubt/sock-it edge case.
  • The game's rules live in one tidy module that I can test really thoroughly, so the game never breaks unexpectedly.
  • Custom WebSocket envelope protocol with personalized payloads so a player's dice never leak to opponents.
  • Your dice are kept secret — opponents can't peek at your roll, even if they tried.
  • React + TypeScript client driven by a reducer that mirrors server events; reconnection and host migration handled.
  • The website updates instantly when someone makes a move — and reconnects you automatically if your wifi drops.
Go gorilla/websocket chi React TypeScript Docker
Play Liar's Dice
// More work

Personal projects

🏆 1st Place SAP Hackathon · $4,000

SAP Share

Full-stack ride-sharing web app to coordinate office commutes — front-end matched co-workers, back-end computed optimal routes. A website that helps coworkers carpool to the office — it figures out the best driving route for everyone.

Next.js Go Express Docker

Fault-Tolerant Distributed KV Store

A System That Never Loses Your Data

Custom RPC over TCP with JSON marshaling and binary metadata. Implemented RAFT leader election and quorum consensus for strong consistency across replica failures. Multiple computers store the same data and stay in sync — even if some of them crash, your data is safe.

Go RAFT Distributed Systems

IPv4 Router

A Router (Like the One on Your Wall)

C-based IPv4 router forwarding datagrams via CIDR longest-prefix matching. Updates checksum, TTL, and byte order — drops invalid packets. The kind of device that figures out where internet messages should go next — but I built mine from scratch in code.

C Networking
// Toolkit

Skills

Languages

Go Python C++ C TypeScript Java SQL HTML/CSS

Frameworks & Libraries

React Next.js Node.js scikit-learn Material-UI JUnit

Infrastructure & Tools

Kubernetes Docker Jenkins Argo CD Redis Git Perforce Unreal Engine 5
// Say hi

Let's talk

Open to interesting backend, distributed systems, and game-server work. Drop me a line — fastest reply is by email. Say hi! I'd love to hear from you. Email is the fastest way to reach me.

leonardociappiciabatti@gmail.com LinkedIn GitHub Play Liar's Dice