Professional traders need order-book tools
Limit orders, market orders, depth, charts, trade history, open orders, portfolio accounting, and execution rules.
FIELD NOTES / WEB3, DEFI & TRADING INFRASTRUCTURE
Order-book speed.
Smart-contract custody.
Meridian is a hybrid DEX trading platform that gives traders a professional CEX-style terminal while keeping deposits, withdrawals, vault custody, and settlement verification anchored to blockchain infrastructure.
WEB3 DEX CASE STUDY
Meridian
Hybrid order book.
Multi-chain custody.
Meridian / ETH-USDC trading terminalHYBRID DEX EXPERIENCE
SPEED + VERIFICATIONThe order book is fast. The money path is conservative.
Trades match off-chain; deposits, withdrawals, custody, and settlement run through verifiable controls.
Open the terminal ↗WalletDepositReserveMatchSettle
DOMAIN
Web3 / DeFi trading
WHAT WE BUILT
Hybrid DEX platform
OUR ROLE
Product, backend, smart contracts & DevOps
01 / THE EXCHANGE PROBLEM
AMMs are not order books.
CEX custody is not Web3.
Token ecosystems need liquidity venues with familiar execution, predictable depth, and professional controls—but users still expect wallet-native access and transparent custody.
Meridian bridges that gap by separating high-frequency trade matching from blockchain custody and settlement verification.
The result is not a swap UI. It is exchange infrastructure: accounting, matching, risk, reconciliation, market data, administration, and smart contracts working as one system.
Every balance change must be defensible
Deposits, withdrawals, locks, fills, and settlement require transactional and chain-verifiable controls.
Operations cannot be invisible
Network lag, withdrawal queues, reconciliation gaps, market-maker activity, and vault TVL must be surfaced.
02 / INSIDE THE PRODUCT
A trading venue,
not just a wallet screen.
The interface covers the full venue lifecycle: connect wallet, deposit assets, trade through a central limit order book, inspect portfolio state, monitor leaderboards, and run operations through admin controls.
CEX-style execution with smart-contract custody behind it.
The trading screen gives users order-book depth, candles, limit and market order controls, open orders, live trades, and verified vault custody status.
TRADER FLOW
Wallet sign-in→Verify deposit→Lock funds→Match order→Persist fills→Broadcast updates→Settle
03 / THE ARCHITECTURE DECISION
Match off-chain.
Prove the money path on-chain.
Putting every order-book action on-chain would make the trading experience slow and expensive. Meridian uses deterministic off-chain matching for execution, while smart-contract vaults and settlement contracts preserve custody and verification boundaries.
Look under the hood ↘01
Wallet-native authentication
EIP-712 challenges verify the trader’s wallet without email/password account creation.
Rust matching engine
Price-time priority, fixed-point arithmetic, in-memory order books, and API-compatible failover.
Upgradeable vault contracts
Multi-chain deposits, withdrawals, settlement anchoring, pausing, roles, and upgrade procedures.
02
Verify before crediting
The backend independently fetches blockchain receipts and decodes vault events before balances change.
03
Debit before withdrawing
Funds are reserved transactionally before any outbound chain action begins.
One venue, two control planes.
Execution stays fast; custody stays verifiable; operations stay inspectable.
Wallet→Accounting→Matching→Settlement queue→Vault contracts
Hybrid does not mean casual custody.
The platform was designed around receipt verification, atomic balance locking, withdrawal safeguards, reconciliation, audit logs, and role-controlled operations.
04 / THE TECHNOLOGY & THE REASON
Trading infrastructure built around
determinism, custody, and recovery.
The stack separates frontend trading experience, API orchestration, deterministic matching, transactional accounting, real-time state, and smart-contract custody so each failure mode can be contained.
MATCHING ENGINE
Rust
Maintains the central limit order book with fixed-point arithmetic and strict price-time priority.
Why Rust?
Matching needs deterministic behavior, predictable performance, and tight control over numeric correctness.
CUSTODY
Solidity contracts
Vault, settlement, withdrawal, role, pause, and upgrade infrastructure across supported networks.
Why upgradeable contracts?
Exchange infrastructure evolves, but upgrades must preserve state and follow controlled procedures.
ACCOUNTING
PostgreSQL + Prisma
Stores balances, locks, orders, fills, withdrawals, deposits, audit trails, and reconciliation state.
Why relational accounting?
Funds, orders, and settlements need transactional integrity rather than eventually consistent guesses.
MARKET DATA
Fastify + WebSockets
Delivers authenticated APIs, account updates, live trades, order-book state, and operational feeds.
Why streaming?
Trading interfaces depend on immediate account, order, and market state changes.
LOW-LATENCY STATE
Redis
Supports hot market data, service coordination, failover state, and high-frequency operational paths.
Why cache carefully?
Fast views can be cached, but money-moving truth remains in transactional systems and chain receipts.
WALLET UX
viem + wagmi
Handles wallet connections, typed signing, approvals, contract interactions, and multi-chain UX.
Why wallet-native tooling?
Traders keep Web3 onboarding while receiving an exchange-style product experience.
Verify wallet
Short-lived EIP-712 nonce proves wallet control before the app session starts.
Confirm deposit
Receipts and vault events are independently verified before crediting balances.
Lock funds
Atomic database updates prevent double spending across concurrent orders.
Execute deterministically
The Rust engine applies price-time priority and fixed-point math.
Reconcile and anchor
Fills, balances, withdrawals, and settlement batches remain auditable.
The supplied screens show trading, portfolio, leaderboard, admin operations, and security/account controls. Live market values shown are demo data and should not be treated as investment information.
Explore the documented platform stack
- Frontend
- Next.js · React · advanced charts · wallet connection · trading terminal · portfolio and admin screens
- Backend
- Fastify · REST APIs · WebSockets · OpenAPI SDK · order validation · accounting workflows
- Matching
- Rust engine · deterministic price-time priority · fixed-point math · TypeScript failover
- Smart contracts
- Solidity · UUPS upgradeable suite · vault custody · settlement anchoring · pause and role controls
- Data
- PostgreSQL · Prisma · Redis · audit logs · reconciliation tables · market data caches
- Web3
- EIP-712 · viem · wagmi · Ethereum · Base · Arbitrum · BNB Chain · partner L1
Financial and custody boundary
This case study describes platform engineering and demo interfaces, not financial advice or a live exchange offer. Production operation requires jurisdiction-specific legal, compliance, custody, security, and market-surveillance review.
Technology names identify the documented implementation, not partnerships or endorsements.
05 / QUALITY AS EXCHANGE CONTROL
The dangerous paths are
the product requirements.
Hybrid exchanges fail when they treat deposits, withdrawals, and matching recovery as edge cases. Meridian makes those paths first-class: verify-first deposit crediting, debit-first withdrawal submission, deterministic matching, reconciliation, and auditable admin intervention.
The product is engineered for the practical reality of trading infrastructure: latency matters, but recoverability and accounting integrity matter more.
EXECUTION
Order book · price-time priority · fixed-point math
CUSTODY
Vaults · chain receipts · settlement anchoring
RISK
Locked balances · safeguards · derivatives-ready controls
OPS
Network lag · withdrawal queue · audit log
Never credit without proof
Deposits require blockchain receipt and vault-event verification before balances update.
Never withdraw unreserved funds
Withdrawal intent starts with a transactional debit or lock before chain submission.
Never corrupt the order book on failover
Engine recovery preserves resting orders, priority, fills, and reconstructed book state.
Never hide operational risk
Admins see network health, lag, custody status, queues, and reconciliation issues.
A CONVERSATION ABOUT YOUR WEB3 TRADING WORKFLOW
Where should your exchange be fast,
and where must it be conservative?
Bring one token ecosystem, custody model, or trading workflow. In 20 minutes, we’ll map the matching path, custody boundary, reconciliation model, and operational controls.
20 minutes · Architecture, risks, and next step
20 minutes · Architecture, risks, and next step