Building Bango: My Journey as CTO of a Web3 Prediction Market Platform

Hey there! I wanted to share the story of one of the most challenging and rewarding projects I've worked on - Bango, a decentralized prediction market platform. As the CTO, I led the technical development from the ground up, and today I want to walk you through what we built, the challenges we faced, and the tech decisions that shaped this product.

What is Bango?

In simple terms, Bango is a platform where users can predict outcomes of real-world events - from crypto price movements to sports, politics, and community-created events. Think of it as the Web3 version of prediction markets, but with a focus on user experience that rivals traditional web apps.

The core idea was simple: make prediction markets accessible to everyone, not just crypto-natives.

Main interface of the Bango platform

The Technical Architecture

Let me break down what we actually built. The entire system consists of four major components that I architected and developed:

1. The Frontend (`bango`)

This is what users interact with - a Next.js 14 application that feels as smooth as any modern fintech app.

Key features I implemented:

• Real-time price charts powered by WebSocket connections
• Gasless transactions - users don't need to worry about gas fees (we handle that)
• Smart wallet integration using Privy for seamless onboarding
• Mobile-first responsive design that works beautifully on any device
• Portfolio tracking with live PnL calculations
• Social features - comments, threads, and community discussions

The trading interface alone was a beast. Getting the buy/sell mechanics right with real-time price updates, slippage protection, and instant feedback took countless iterations.

The prediction trading interface

2. The Backend Engine (`bango-engine`)

This is the brain of the operation - a Node.js/Express server that handles everything from user management to market resolution.

What it does:

• Real-time WebSocket server - pushing trade updates and price changes to thousands of concurrent users
• Automated Market Making (AMM) price service - calculating market prices in real-time
• Cron jobs for market resolution, reward distribution, and data sync
• RESTful API with proper rate limiting, authentication, and validation
• Activity tracking and analytics

I built this with scalability in mind. The WebSocket implementation uses room-based subscriptions so users only receive updates for events they're watching - no unnecessary data transfer.

Architecture highlights:
├── Real-time WebSocket (Socket.IO)
├── MongoDB for flexible data storage
├── Redis for caching (optional)
├── Docker containerization
├── CI/CD with GitHub Actions
└── Comprehensive logging with Winston

3. The Admin Console (`bango-console`)

Every platform needs an admin dashboard, and this one handles:

• Market creation and management
• Fee configuration across different chains
• User management and moderation
• Market resolution interface
• Analytics dashboard

Built with Next.js and a clean UI using Radix components. Nothing fancy, but it gets the job done efficiently.

The Bango admin console

4. Smart Contracts (`bango-contracts-base`)

This is where I collaborated with another developer who was strong in Solidity. Together, we built the on-chain infrastructure:

The MarketAMM Contract - the heart of our prediction markets:

• Constant Product AMM for price discovery
• Conditional Tokens (based on Gnosis protocol) for outcome positions
• Configurable fee distribution between LPs, creators, and platform
• Gasless transaction support via meta-transactions
• Multi-chain deployment (Avalanche, Base, and more)

The smart contracts handle:

• Creating prediction markets with custom outcomes
• Buying and selling outcome tokens
• Adding/removing liquidity
• Market resolution and payout redemption
• Fee accrual and distribution

Architecture diagram of the smart contract system

Technical Challenges & Solutions

Building Bango wasn't straightforward. Here are some of the interesting problems we solved:

Challenge 1: Gasless Transactions

Problem: Most users don't want to deal with gas fees. It's confusing and creates friction.

Solution: We integrated with 0xGasless and implemented meta-transactions. Users sign transactions, and we relay them, covering the gas costs. The UX became seamless - users just click "Buy" and it works.

Challenge 2: Real-time Price Updates

Problem: Prediction markets need real-time prices. Every trade changes the odds, and all users need to see this instantly.

Solution: I built a WebSocket infrastructure with event-specific rooms. When a trade happens:

• The backend calculates new prices from the contract
• Broadcasts to all users watching that specific event
• Frontend updates prices without any page refresh

The result? Sub-second price updates across all connected clients.

Challenge 3: Complex Fee Distribution

Problem: We needed flexible fee sharing between liquidity providers, market creators, and the platform.

Solution: We built an accrual-based fee tracking system in the smart contract. LPs earn fees proportional to their share of the pool, and they can withdraw anytime without affecting the market.

Diagram showing the fee distribution flow

Challenge 4: Multi-chain Deployment

Problem: We wanted to support multiple blockchains without maintaining separate codebases.

Solution: Abstracted chain-specific logic into configuration files. Same contracts, same backend, different chains. The frontend automatically adapts based on the user's connected network.

The Tech Stack

Here's what powers Bango:

Frontend:

• Next.js 14 (App Router)
• TypeScript
• Tailwind CSS
• Privy for authentication
• TanStack Query for data fetching
• Socket.IO client for real-time updates
• Recharts for data visualization

Backend:

• Node.js + Express
• TypeScript
• MongoDB + Mongoose
• Socket.IO for WebSockets
• Winston for logging
• Docker for containerization

Smart Contracts:

• Solidity 0.8.24
• OpenZeppelin contracts
• Gnosis Conditional Tokens
• Hardhat for development
• Multi-chain: Avalanche, Base, and more

Infrastructure:

• Vercel (frontend hosting)
• Docker containers (backend)
• GitHub Actions (CI/CD)

Features I'm Most Proud Of

The Trading Interface

Getting the buy/sell UI right was crucial. I built it to show:

• Real-time odds for each outcome
• Instant calculation of potential returns
• Slippage protection
• Position tracking
• One-click actions (50%, 100%, Max)

Users can trade without ever seeing a blockchain transaction. That's the experience I was going for.

Detailed view of the trading panel

Community Markets

Users can create their own prediction markets. This was huge for engagement. The workflow:

• Creator proposes a market
• Admin approves (for quality control)
• Creator provides initial liquidity
• Market goes live
• Creator earns a cut of trading fees

The Referral System

Built a full referral system with tracking, rewards, and leaderboards. Every user gets a unique link, and both referrer and referee benefit when trades happen.

Mobile Experience

I spent a lot of time making the mobile experience feel native. The trading panel slides up from the bottom, gestures work naturally, and everything is touch-optimized.

Mobile-optimized trading experience

Lessons Learned

Building Bango taught me a lot:

• Web3 UX doesn't have to suck - With the right abstractions (gasless tx, smart wallets), you can hide blockchain complexity from users.
• Real-time is hard but worth it - WebSockets added complexity, but the instant feedback loop is essential for trading platforms.
• Smart contract security is paramount - We went through multiple audits and testing cycles. One bug could be catastrophic.
• Start simple, iterate fast - We launched with basic features and added complexity based on user feedback.
• Multi-chain from day one - Building with chain abstraction from the start saved us tons of refactoring later.

What's Next?

While I've moved on from Bango, the experience shaped how I think about building Web3 products. The key insight? Users don't care about blockchain - they care about the experience. Everything we built was designed to make the blockchain invisible while keeping its benefits (transparency, ownership, trustlessness).

If you're building in the Web3 space and want to chat about prediction markets, gasless transactions, or just technical architecture in general - feel free to reach out!

Tech Credits

• My Role: CTO - Architecture, Frontend, Backend, DevOps
• Smart Contracts: Collaborative effort with another team member
• Founder: Separate from technical team

Thanks for reading! If you found this interesting, check out my other projects or connect with me.

Bango platform statistics and achievements

Tags: `Web3` `Prediction Markets` `DeFi` `Next.js` `Node.js` `Smart Contracts` `Solidity` `TypeScript` `WebSockets` `Blockchain`