It is time to unify Ethereum - privately.
Top teams are invited to build on Aztec’s privacy-preserving Layer 2 to create cross-chain applications that extend its privacy and decentralization guarantees to all major L2s. With up to US$150,000 in funding, the goal is to help pioneer the next generation of private, scalable, and interoperable solutions.
This is just the beginning of Aztec’s broader mission to bring privacy to all Ethereum chains—something we believe is critical for mass adoption. Over the past eight years, Aztec Labs has been refining Layer 2 privacy and scalability, starting with zk.money in 2021, and followed by Aztec Connect and Noir in 2022, culminating in the upcoming public testnet launch happening later this year.
With how mature ZK and account abstraction have become, it’s the perfect moment for talented builders to leverage Aztec’s unique execution environment—private and public states, seamless composability between private and public functions, and native account abstraction—to prevent further liquidity fragmentation and accelerate the future of Ethereum.
Submit your proposal on or before Sunday 23 March 2025 for a chance to receive funding and support. For more inspiration, check out Appendix 1 on Potential Areas of Interest. Together, let’s unify Ethereum—privately.
EDIT
This deadline has now passed. Winners of this grant will be announced by 11th April 2024
The Aztec L2 roadmap:
Grant Details and Submission Format
We are excited to support teams in their journey to build on Aztec. We will provide stipends of up to US$50,000 per team to help offset the costs of research and development. We are particularly interested in teams with a long-term vision for privacy, the Aztec ecosystem and a commitment to contribute to the Aztec stack and developer community.
To ensure consistency and facilitate the review process, please adhere to the following submission format:
Title: Team/product name
Contact Details: How can we contact you? (Signal, email, etc.)
Summary: In 300 words or less, describe the cross-chain app you want to bridge, the other L2 Testnet you will connect to and the kind of bridge you want to build.
Start and End Date: It is recommended that work starts on Tue 1 April 2025 and require a functional version be released on the Aztec Testnet by June 2025.
About You: A short paragraph with details about your team’s background, relevant experience and expertise. Show us that you have what it takes and why you are best placed to execute the long-term mission of creating an interop solution to bring privacy to your favourite L2!
Details you should cover:
- The cross-chain app you plan to demo
- What kind of bridge you will build and why
- How the design will meet the requirements
- Technical hurdles that will need to be overcome
- The user flow and journey
Make this section unique and try to stand out from other proposals. You could even write an example bridge contract or show a UI to stand out!
Grant Milestones and Roadmap: Submit a timeline and milestones to deliver on the requirements. We expect 3-5 milestones to get to an MVP-ready cross-chain app deployed between Aztec’s testnet and another L2, and 2-3 items dedicated to future work (post-launch improvements, feature additions, and mainnet launch). Please indicate your longer-term roadmap and how you want to keep building in the long run.
Grant Amount Requested: Any grant requests over US$50,000 will be immediately rejected. Successful projects may get further grant support post-launch, although it is not guaranteed.
Grant Budget Rationale: Explain comprehensively why you are requesting the amount of funds, and how it relates to milestones and timelines.
Questions: Any outstanding questions. Any confidential questions can also be sent to rahul[at]aztec-labs[dot]com
Submissions should be created as a new post on this forum, tagged bridge and rfgp. Once the new post is created, please refer back to this RFGP and post the link to your proposal as a comment.
Please submit proposals by Sunday 23 March 202.
Requirements
- Bridge to another L2 testnet
- Cross-chain demo app
- A UI for executing transactions in Aztec or another L2 from Aztec – read below for example flows.
- Bridge design:
- What kind of bridge do you want to build? Detail your trust assumptions. Trusted parties are acceptable for this MVP, but your roadmap should include a path to remove single points of failure (e.g., via RIP 7755, a light client approach, or ZK proofs). For additional information refer here.
- Flows:
- Private deposit into Aztec from any chain.
- Private withdrawal from Aztec to another L2 to execute a cross-chain intent.
- Public deposits and withdrawals (optional).
- Note: give extra thought to the withdrawal flow from Aztec, since a user would withdraw to execute cross-chain intents.
- An example app could be a flow like
- Control assets on another chain via a private multisig on Aztec
- Maintain zk proof of passports on Aztec and use that for credit scores or other regulatory features apps on public L2s require to get institutional adoption.
- Simply paying someone privately on another L2.
- Proving an NFT ownership on another chain to get access to special items.
- Some more sample flows are mentioned in the additional context document.
- Gas Fee Management:
- Your solution should sponsor gas fees for users on Aztec. Refer to additional context document here.
- Our solution should sponsor gas fees for the other L2 (e.g., EIP-7702/4337) (optional).
- Edge Cases:
- Outline how you’ll address cancellations, L2 re-orgs, refunds for solvers or other edge cases you can think of.
- UX:
- Outline how you plan to mitigate UX, pre-confirmations and expected bridging time. Using EIP-7702 or 4337 makes it so only one transaction is needed on each chain.
- In the short term, a user would need both an EVM wallet and an Aztec wallet. Long term, it should move to users requiring just 1 wallet (which can generate relevant permits for Aztec transactions).
A deeper understanding of the types of bridges Aztec can support will clarify these requirements. Please refer to the following document with additional context for further details.
FAQs
Are there existing wallets, explorers, and L1 token bridges for Aztec testnet already?
At launch, we anticipate testnet to have several wallets, explorers, and L1 to L2 bridges live.
Is Aztec EVM-compatible?
No, but it is a Turing-complete smart contract environment that allows for both public and private execution. Read more here.
Where do we build this? When testnet and mainnet?
- You will start working on the Sandbox, a local development environment (most similar to Anvil of Ethereum) along with Aztec.nr smart contracts and TXE (our testing toolkit).
- A decentralized testnet is expected to go live in Q1 2025.
- Mainnet Ignition is expected to happen by mid-2025.
Are there any smart contract standards?
The Aztec Labs’ monorepo also has some sample contracts and apps.
DeFi Wonderland has also recently started working on contract standards here
Do I need ALL the requirements done by the June deadline?
No. We only need a minimal working cross-chain app deployed to testnet by June 2025. You don’t have to fulfill all requirements, but please provide a roadmap showing priorities and timelines. We expect at least one milestone to come after the deadline. Throughout the process, you’ll work closely with Aztec Labs and our ecosystem to address blockers and iterate.
Do you have a preference for certain L2 testnets?
No! All of Ethereum is one.
Any EIPs for standards that I need to follow?
No! This is intentionally EIP/ERC/RIP agnostic.
What kind of bridges can I build?
Refer to this doc for additional context.
What should I know about Aztec to build a good bridge?
Refer to this doc for additional context.
Appendix 1: Potential Other Areas of Interest
- UMA’s Optimistic Oracle - create an Aztec variant to this or integrate UMA’s Optimistic Oracle into the Aztec testnet. This is useful for prediction markets, bridges, and generic dispute resolution.
- Blocknative’s gas.network - extend it to have Aztec support. Bridges want to charge fees based on gas fees of the other network. This either requires a trusted oracle (provided by the filler) or ideally some onchain contract that tells you the gas situation in the other chain. Blocknative’s gas.network is exactly that.
- Privacy-preserving RPC providers - RPC services are useful to send a user’s transaction to a node or to query state information. However, this leaks to an RPC what a user wants to do, their address, and IP address. Consider integrating a mixnet like Hopr or building a privacy-preserving RPC proxy.
- FPC (Fee Payment Contracts) - most similar to paymasters in EVM land. FPCs act as the fee payer on behalf of the end user and instead allow users to pay fees in any token they accept. Through FPCs, users could also pay fee privately and accept refunds from sequencers without leaking their address. Read more here.
Disclaimer
The published request for proposal and ideas herein are explicitly published as discussion points to invite community feedback in the community forums. Robust design and developer discussion is the best way for the community to collectively secure and govern the network as well as ensure cross-chain interoperability. Any ultimate governance and cross-chain designs will be a result of the analysis and feedback of the community.The information set out herein is for discussion purposes only and does not represent any binding indication or commitment by Aztec Labs and/or affiliates and their employees//consultants to take any action whatsoever, including relating to the structure and/or any potential operation of the Aztec protocol or the protocol roadmap. In particular: (i) nothing in this post (and any response to this post) is intended to create any contractual or other form of legal, investment, financial, tax or advisory relationship between Aztec Labs or third parties who engage with such posts (including, without limitation, by submitting comments, a proposal and/or responding to posts including any medium such as X, Discord, etc), (ii) by engaging with any post, the relevant persons are consenting to Aztec Labs’ use and publication of such engagement and related information on an open-source basis (and agree that Aztec Labs will not treat such engagement and related information as confidential), and (iii) Aztec Labs is not under any duty to consider any or all engagements, and that consideration of such engagements and any decision to award grants or other rewards for any such engagement is entirely at Aztec Labs’ sole discretion. Please do not rely on any information on this forum for any purpose - the development, release, and timing of any products, features or functionality remains subject to change and is currently entirely hypothetical. Nothing on this forum post should be treated as an offer to sell any security or any other asset by Aztec Labs or its affiliates, and you should not rely on any forum posts or content for advice of any kind, including legal, investment, financial, tax or other professional advice.
Introducing Our Proposal: Confidential Cross-Chain Bridging for Aztec 
Introducing Our Proposal: Cross-Chain Messaging for Aztec 
Built on ERC-7683 Cross-Chain Intents
