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Event Replay: Arcshop- Introducing Bridge Kit

Posted Dec 10, 2025 | Views 176.4K
# USDC
# Bridge Kit
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Speakers

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Tobias Golbs
Eng Manager @ Circle
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Dave Musicant
Sr Director, Engineering @ Circle

SUMMARY

Bridge Kit Arcshop

Introducing Bridge Kit — a new developer toolkit designed to make it dramatically easier to integrate CCTP and build crosschain USDC experiences.

Circle engineers Dave Musicant and Tobias Golbs will walk through how Bridge Kit abstracts away complex chain logic, wallet providers, and app-level workflows, allowing developers to launch crosschain features faster and more reliably. You’ll learn how to integrate crosschain USDC flows in under 10 lines of code and see how developers can implement built-in monetization using the FeeTaker method.

The session includes a full live demo, featuring:

  • Arc → Ethereum USDC transfers on testnet
  • Switching to Arc → Solana with near-zero code changes
  • Using Circle Wallets via adapter
  • Adding developer fees to your own wallet
  • We’ll highlight improvements to developer experience, setup time, composability, and mainnet deployment. The engineers will also cover available resources including tutorials, documentation, and community support.

Visit our Docs: https://developers.circle.com/bridge-kit

Arc is offered by Circle Technology Services, LLC (“CTS”). CTS is a software provider and does not provide regulated financial or advisory services. You are solely responsible for services you provide to users, including obtaining any necessary licenses or approvals and otherwise complying with applicable laws.

Arc has not been reviewed or approved by the New York State Department of Financial Services.

The product features described in these materials are for informational purposes only and may be modified, delayed, or cancelled without notice at the sole discretion of Circle Technology Services, LLC. Nothing herein constitutes a commitment, warranty, guarantee, or investment advice.

USDC is issued by regulated affiliates of Circle. A list of Circle’s regulatory authorizations can be found here: https://www.circle.com/legal/licenses

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CONTENT & TRANSCRIPT

Intro and guests

Sam (Host): Hey, everybody. We’re very excited here for another livestream. We’ve got Dave Musikant, Senior Director of Engineering at Circle, and Tobias Gobbs. Today we’re talking about Circle Bridge Kit, one of the most popular tools we’ve been seeing from the community.
Dave, quick intro.
Dave Musikant: Great to meet everyone. I’m Dave Musikant, Senior Director of Engineering at Circle, leading the Stablecoin Solutions Group. Bridge Kit is something we worked on for a while, and we’re excited about what we’re doing with it.
Sam: Tobias?
Tobias Gobbs: I’m Tobias Gobbs, Engineering Manager at Circle. I led the team building Bridge Kit. We’re excited to get feedback because it took a while to build, and now we want to show it to the world.


Dave: design goals and architecture

Dave: I’ll give a quick overview of the developer experience principles and the architecture, then Tobias will do a live demo.

Developer experience principles

  • Abstract away the hard parts with sane defaults, but include escape hatches when you need low-level control.
  • Reduce fragmentation across:
  • Chains (EVM vs non-EVM)
  • Wallet providers
  • Frameworks (viem, ethers, etc.)
  • Meet developers where they are: don’t force a full stack rebuild; plug into existing tooling.
  • Pluggability: don’t lock developers into one choice.
A core principle: easy to use correctly and hard to use incorrectly.

Architecture overview

There’s a lot of fragmentation. Implementing CCTP directly across multiple chains can be a lot of code.
Bridge Kit tackles two main fragmentation areas:
  1. Chain adapters
  1. Framework-based adapters for EVM chains (e.g., viem and ethers).
  1. Non-EVM adapters (e.g., Solana).
  1. You interact with adapters the same way, so code doesn’t need to change when switching chains.
  1. Wallet provider adapters
  1. Allows swapping wallet backends (e.g., Circle Wallets, Fireblocks, Privy, browser wallets) without rewriting the rest of your code.
  1. Wallet adapters can behave like “interfaces into chains,” just like chain adapters.
  1. Pluggable providers
  1. Providers are “capability providers.” Example: a CCTP v2 bridging provider.
  1. Circle can add more providers, and developers can implement their own providers and plug them in.
  1. The kit orchestrates providers and uses adapters to execute onchain operations.


Tobias: live demo (EVM ↔ EVM)

Tobias: I’ll walk through a demo. I’ve installed Bridge Kit and the viem v2 adapter.
I instantiate the adapter (here with a private key from environment variables). Then I create the kit, add an event listener to log progress, and call  bridge() .
Under the hood, for CCTP, the flow is:
  1. Approve token allowance
  1. Burn USDC via Token Messenger
  1. Fetch attestation from the offchain attestation service
  1. Mint USDC on the destination chain
Tobias (running code):
  • Approve succeeded
  • Burn succeeded
  • Attestation received
  • Mint succeeded
Because this is a fast transfer, a small USDC fee is taken, and the destination receives slightly less than 1 USDC.


Tobias: switching to Solana (EVM ↔ Solana)

Tobias: Now I’ll show cross-ecosystem bridging. I bring in the Solana adapter (already installed), instantiate it with a Solana private key, then switch the  sourceAdapter  /  destinationAdapter  in the same  bridge()  call and set the destination chain to Solana.
That’s basically it: add adapter, configure it, drop it into the same bridge call. The adapter abstracts Solana specifics.
Tobias (running code):
  • Approve
  • Burn
  • Attestation
  • Mint on Solana successful
Result: bridged from an EVM chain to Solana with minimal changes.


Tobias: wallet provider adapter (Circle Wallets)

Tobias: Bridge Kit also supports wallet provider adapters. For example, there’s a Circle Wallets adapter. I can configure it with an API key and entity secret.
One difference: with some wallet providers you can control multiple wallets on multiple chains simultaneously, so the kit may require explicit source and destination addresses.
Tobias: You can also mix adapters: Circle Wallets on one side, Solana on the other, or custom adapters like Fireblocks.


Reliability: retry / resume

Tobias: Bridge Kit also exposes a retry method. If something fails mid-flow (network blip, gas issues, etc.), you can resume from the last known state instead of rebuilding the bridging logic manually.


Feature: native fee taking

Tobias: Another feature is fee taking. You can configure an extra fee amount. At burn time, the kit takes the fee from the user (in the same asset), splits it 90/10:
  • 10% to Circle (platform fee)
  • 90% to the developer recipient address
Then the main transfer proceeds through CCTP.
Tobias (after running): In the burn transaction you can see:
  • The total pulled from the user
  • The split to fee wallets
  • The remainder forwarded into the Token Messenger for bridging


Q&A and clarifications

Sam: A question came up: is it still burn-and-mint?
Tim (“Silence” in chat): Yes. Burn-and-mint happens via CCTP, but Bridge Kit abstracts it.
Sam: Fee taking works across supported chains; kit contracts handle logic. Also: kit contracts are audited twice by third-party auditors (as noted in chat).
Dave: Some chains can be slower depending on finality. The kit won’t time out; it can run end-to-end, and also supports restarting from intermediate state.
Tobias: Security-wise: Bridge Kit doesn’t add extra trust assumptions on top of CCTP. It’s orchestrating standard smart contract calls and attestations; the kit is “glue” to avoid everyone re-implementing bridging.
Dave: Bridge Kit currently supports CCTP v2. CCTP v1 is deprecated, so the kit focuses on v2.
Dave (open source question): Not open source yet. Under discussion. However, the system is pluggable: developers can build and publish their own adapters and providers compatible with the kit.
Dave (Aleo / USDCX): There are plans to add support related to USDCX.
Dave (EURC): Not supported today; it’s being discussed. Feedback helps prioritize.
Tobias (other tokens): Out of the box, it’s USDC via CCTP v2. Developers can implement additional providers for other tokens if they want.
Dave (Stellar): Solana is supported. Stellar is not supported by the kit today because it’s built around CCTP v2 support.


Closing

Sam: We’ll post links to the docs and quick start. Join the Discords (Build on Circle / Build on ARC) to keep the conversation going. We’ll likely schedule a Discord AMA after folks try the kit and come back with questions.
Dave: We want feedback. Tell us what you’re building and what support you need.
Tobias: We’re developers too. The goal is to make bridging something you don’t have to re-implement from scratch.
Sam: Thanks everyone. See you in Discord.
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