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Brian.

Full-stack Software Engineer

Brian Joseph Keyrupan

Web apps across Web3, DeFi, NFT, and marketplaces — React/Next.js, NestJS, Python, PostgreSQL, Solidity, and AWS.

Professional experienceGitHubLinkedIn

About

I'm a full-stack engineer with 3+ years shipping production dashboards, smart contracts, data pipelines, risk monitoring agents, and multi-chain integrations. I care about clear product surfaces, reliable ops, and code that teams can extend.

Focus
Web Developments, Dapps, Smart Contracts, Web3, DeFi, NFTs, marketplaces
Currently Based in
Jakarta, Indonesia
Open to relocate or remote roles globally
Contact
bkeyrupan@gmail.com+6281586688888WhatsApp

Skills

Tools and stacks I use regularly across the stack.

Languages

  • TypeScript
  • JavaScript
  • Python
  • Solidity
  • SQL

Frontend

  • React
  • Next.js
  • TanStack Router
  • TanStack Query
  • Tailwind CSS
  • React Native
  • Vue.js

Backend & data

  • NestJS
  • PostgreSQL
  • Drizzle ORM
  • Alembic
  • Dagster
  • REST
  • GraphQL
  • Supabase
  • OAuth

Web3

  • Solidity
  • Foundry
  • Viem
  • Wagmi
  • JSON-RPC
  • ERC-721
  • ERC-1155
  • ERC-165

Infra

  • AWS SQS
  • AWS KMS
  • Redis
  • Lambda
  • Docker
  • Slack bots
  • Swagger

Experience

Roles and initiatives where I owned features end to end.

  1. Software Engineer

    Mon Co. (formerly LiquidX) — Mon Protocol Team

    LinkedInWebsite

    Mar 2024 – Present

    Yield Monitoring Service

    • Designed and implemented a Dagster pipeline (assets, jobs, schedules, asset checks, sensors) for market snapshots and risk/metrics computation, stored in PostgreSQL with Alembic migrations for schema evolution.
    • Integrated multiple DeFi protocols (Morpho, Aave, Athena, Hyperliquid) via JSON-RPC / Web3, GraphQL, and typed protocol clients; modeled shared abstractions for ingestion and configuration.
    • Built downstream analytics with pandas, numpy, and quantstats (e.g. rolling returns, volatility, Sharpe ratio, Sortino ratio, liquidity, and utilization metrics). Added operational reliability: configurable Slack run-failure sensors on critical jobs.
    • Impact: gave the team automated DeFi market snapshots and risk metrics in PostgreSQL—replacing ad-hoc pulls with scheduled pipelines and alerting on failures.

    Havenfi

    app.havenfi.co/dashboard

    • Shipped a React dashboard with TanStack Router (file-based routes) and TanStack Query for cached server state, charts (Recharts), and Tailwind 4 + shadcn/Radix UI aligned to a design system.
    • Implemented wallet connectivity and chain-aware reads with wagmi, viem, and Reown AppKit.
    • Developed and maintained REST endpoints in NestJS for domains including vaults, markets, token prices, users, auth, admin, audit, and reallocation-related flows; used Swagger for API documentation.
    • Python repo deploying Hypernative risk agents for HavenFi: APY monitoring, oracle vs reference price checks, and Morpho-related on-chain reads.
    • Impact: production dashboard and APIs for live vault/Morpho exploration plus operational risk monitoring in one product surface.

    Collect Fun

    Live appInstagram

    • Shipped a gacha-style mystery pack experience where pulls are backed by real PSA-graded Pokémon inventory; BrainCloud powers the game backend, with Next.js for the web app and NestJS for integrations—I implemented Stripe for pack purchases, payment webhooks, and Stripe’s voucher system.
    • Integrated Amplitude for web analytics to track product usage and engagement across the collector experience.
    • Built in-app claim and intake flows so collectors who win physical slabs can submit shipping details and the team can verify outcomes before fulfilling graded cards.
    • Impact: connected on-chain collectibles and marketplace flows to accountable physical stock—end to end from pack opening through digital inventory to shipped PSA slabs with less manual back-and-forth.

    Holodeck

    • Built an internal dashboard for Mon Co.'s finance team—connects Binance, Bybit, Gate, MEXC (API keys) and Ethereum-family addresses (read-only), then shows unified totals, 24h volume, daily change, holdings, allocation charts (Recharts), and recent transactions.
    • Impact: gave the internal finance team a single view of CEX + on-chain exposure.

    Slack Copy Agent

    • Built an internal Slack bot so project managers could chat to update frontend copy—OpenAI API on the backend to handle requests, GitHub API to open PRs into project repos.
    • Impact: Project managers could ship wording changes through Slack + reviewable PRs instead of blocking on engineering for every copy tweak.

    Shiny RWA Platform

    sequence.xyz/blog/sequence-powers-collectshiny-pokemon-marketplace

    • Designed the NFT redemption and marketplace infrastructure for PSA-graded Pokémon cards.
    • Built robust backend systems using NestJS and TypeScript for admin panel functionality.
    • Developed smart contracts (ERC721AC, ERC1155, ERC165) for NFT management and access control.
    • Impact: enabled PSA-graded card redemption and marketplace flows for Collect Shiny (Sequence partnership)—physical inventory tied to on-chain tradeability.

    Mon Protocol Launchpool

    app.pixelmon.ai/launchpool

    • Developed the frontend in Next.js and TypeScript for the token distribution platform.
    • Developed and deployed smart contracts across 10+ mainnets (Ethereum, Base, Blast, Arbitrum, BNB, Optimism).
    • Impact: facilitated partnerships with 30+ projects, distributing $6M+ worth of tokens to users.
    • Built a comprehensive admin panel for business operations and reward management.

    Pixelmon E3 Evolution

    WikiOpenSea

    • Developed Solidity smart contracts for Evolution 3 (audited by Onyx Labs): collectors burn Serum 3 (ERC-1155) to evolve Evolution 2 Pixelmon into Evolution 3 on-chain, with rules and flows aligned to the product spec.
    • Built the Evolution 3 frontend so owners can complete the on-chain evolution with clear wallet flows, ERC-1155 Serum 3 and Evolution 2 requirements, and transaction feedback.
    • Impact: 438 Evolution 2 Pixelmon NFTs evolved through the launch.

    MON ID

    • Built the production Next.js MON ID storefront so players can buy in-game currency for Wardens Ascent and Pixelmon TCG — game discovery, shop inventory, and on-chain checkout — with Thirdweb (ecosystem wallet, SIWE-backed auth, account abstraction with gas sponsorship), typed clients to MON ID, Auth Sphere, and payments APIs, TanStack Query and Jotai, Zod-validated environment config and Mon UI.
    • Shipped multi-chain configuration (e.g. Avalanche and Base for token and sale contracts), top-up flows, transaction history with filtering, and responsive layouts for store and checkout.
    • Implemented the TypeScript/NestJS payments API for EIP-712–signed purchase intents across multiple EVM chains — Drizzle/PostgreSQL for intents, webhooks, price pegs, and append-only state transitions; Redis; AWS SQS and KMS-backed signing with viem for receipt and log validation against sale contracts.
    • Exposed versioned REST with Swagger, JWT and API key auth, HMAC-verified indexer webhooks (Alchemy and custom indexers).
    • Impact: one commerce layer for Wardens Ascent and Pixelmon TCG with gas-sponsored checkout and reliable async payments across multiple EVM chains.

    Mon Protocol Questing

    • Revamped Questing UI and shipped smart contract integration for 15M $MON token distribution.
    • Impact: supported a 15M $MON distribution campaign with updated questing UX and on-chain integration.

    GVRN

    LinkedInWebsite

    • Implemented the initial GVRN dashboard UI in Next.js—layout, navigation, and responsive patterns for the first product surface.
    • Impact: delivered the first usable dashboard shell GVRN shipped with; the live product at gvrn.ai has since evolved beyond this build.

  2. Software Engineer Intern

    F-Secure Malaysia

    WebsiteLinkedIn

    Aug 2022 – Nov 2022

    • Migrated R&D backends to Docker and built automated testing with Python and Robot Framework.

Professional experience

Products and platforms I've helped ship.

Hackathons

ETHGlobal builds and bounties

  • PredPump

    ETHGlobal Thailand — Nov 2024

    Open prediction market — 4th Scroll, Push bounty, Blockscout prize.

    Showcase

  • ReversiFi

    ETHGlobal Singapore — Aug 2024

    Non-custodial crypto payment SDK.

    Showcase

  • FiatX

    ETHGlobal Sydney — May 2024

    P2P fiat ramp with World ID and Chainlink VRF.

    Showcase

  • Footy Stars

    ETHGlobal Istanbul — Nov 2023

    Provable football sim with ZKPs and EZKL — finalist, 2nd SportFi, Best on Scroll.

    Showcase

Personal projects

Solo experiments on Solana and the browser — shipping small tools and trading-adjacent UX outside of hackathon weekends.

  • Solana meme coin blind box

    Web app

    Users buy random coins from configurable boxes (e.g. graduated tokens above a market cap). Jito bundler batches swap transactions from the Jupiter API; NestJS backend.

    • Solana
    • Jupiter
    • Jito
    • NestJS

  • Solana token swap extension

    Chrome extension

    Detects token addresses in tweets, surfaces price data, and enables swaps via Jupiter APIs.

    • Chrome extension
    • Jupiter API
    • TypeScript

Education

Bachelor of Software Engineering

Asia Pacific University of Technology and Innovation (APU), Malaysia

Nov 2020 – Nov 2023

CGPA 3.5