Bridge Architectures
Lock-mint and burn.
Bridge Architectures is a free Web3 & DApp Development Fundamentals lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Web3 & DApp Development Fundamentals learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Bridge Design Categories
Bridges differ mainly in how they represent assets on the destination chain and who secures the transfer.
The main architectures are lock-and-mint, burn-and-mint, and liquidity pool bridges.
Lock-and-Mint Architecture
In lock-and-mint, the original asset is locked on the source chain and a wrapped version is minted on the destination.
The wrapped token is fully backed by the locked collateral in the bridge contract.
Source: lock 100 USDC in bridge
Dest: mint 100 wUSDC to userBurn-and-Mint Architecture
In burn-and-mint, the token is burned on the source chain and an equal amount is minted natively on the destination.
This requires the token contract on both chains to be controlled by the bridge, but avoids wrapped representations.
Source: burn 100 TOKEN
Dest: mint 100 TOKEN (native)Liquidity Pool Bridges
Liquidity pool bridges hold reserves of the same asset on both chains.
You deposit into the source pool and instantly withdraw from the destination pool — no minting, just a swap from existing liquidity for a fee.
Source pool: user deposits 100 USDC
Dest pool: user receives 99.9 USDC
// 0.1% fee to liquidity providersWho Verifies the Transfer?
Every bridge needs to verify the source event happened. Verification models include:
- External multisig/federation
- Optimistic with fraud proofs
- Light client / native verification
- ZK proofs
Multisig and Federated Bridges
The simplest (and historically most exploited) model uses a multisig of signers who attest transfers.
Security equals the honesty of those signers — if enough keys are compromised, funds can be stolen.
require signatures >= threshold
// e.g. 5 of 8 validators must signOptimistic Bridges
Optimistic bridges assume a transfer is valid and allow a challenge window where watchers can dispute fraud.
This adds a delay but reduces reliance on a trusted signer set.
Light-Client (Native) Bridges
A light-client bridge verifies the source chain's block headers and proofs directly on the destination chain.
This is the most trust-minimized approach — security comes from the chains themselves, not external parties.
ZK Bridges
ZK bridges use validity proofs to attest that an event occurred on the source chain.
The destination verifies a succinct proof, combining strong security with efficient on-chain verification — an emerging frontier.
Canonical vs Generalized Bridges
A canonical bridge is purpose-built for one chain pair (e.g. an L2's official bridge). A generalized bridge connects many chains through one protocol.
Generalized bridges are convenient but concentrate risk across all connected chains.
Putting It Together
Bridge architectures combine an asset model (lock-mint, burn-mint, or liquidity pools) with a verification model (multisig, optimistic, light client, or ZK).
The verification model largely determines safety. Next we study why bridges get exploited.
Quick Check
Test your bridge architecture knowledge.
Recap: Bridge Architectures
You learned that:
- Asset models: lock-and-mint, burn-and-mint, liquidity pools
- Verification: multisig, optimistic, light client, ZK
- Light-client and ZK bridges are most trust-minimized
- Canonical vs generalized bridges trade convenience for concentrated risk
Next: bridge security risks.
Frequently asked questions
Is the “Bridge Architectures” lesson free?
Yes — the full text of “Bridge Architectures” is free to read here on the web, and the Web3 & DApp Development Fundamentals course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Web3 & DApp Development Fundamentals course, upgrade to CoddyKit PRO.
What will I learn in “Bridge Architectures”?
Lock-mint and burn. You practise Web3 & DApp Development Fundamentals with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Web3 & DApp Development Fundamentals?
No prior experience is required. Web3 & DApp Development Fundamentals on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Bridge Architectures” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Web3 & DApp Development Fundamentals lesson?
Yes. Every Web3 & DApp Development Fundamentals lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Cross-Chain Concepts
- Bridge Architectures
- Bridge Security Risks
- Messaging Protocols