Umbra is a protocol that lets you get paid privately on Ethereum and Layer 2 networks.

About Umbra

As a protocol, Umbra defines a simple set of standards, coupled with a singleton smart contract instance, to enable stealth addresses on Ethereum. With a stealth address, a payer can send Ether or ERC20 tokens to an address controlled by the receiver, but no one except the two parties know who that receiver is.

On chain, the transaction looks like a simple transfer to an otherwise unused address on the Ethereum network. Off chain, the sender has used a public key published by the receiver to generate the new address. By encrypting the data used to generate the address, and announcing it via the Umbra smart contract, the sender can let the receiver know they’ve sent them a payment to a new stealth address. Only the receiver can generate the private key needed to withdraw the funds.

By leveraging meta-transactions, Umbra enables withdrawers to pay relayers for gas using the tokens they’ve received. This avoids the need to fund stealth addresses with Ether before withdrawing.

Project Status

The Umbra MVP went live in June 2021. You can visit https://app.umbra.cash to send and receive stealth payments using Umbra.

Since our launch, we've made many iterative improvements based on user feedback. These included better mobile responsiveness, a simpler key registry system, faster scanning when searching for received funds, and other UX enhancements. We've also launched Umbra on Polygon, Optimism, and Umbra, and made huge improvements to our relay system to make token withdrawals faster and cheaper.

Since launch, Umbra has processed over 270,000 payments across all networks, transacting assets valued nearly $500 Million dollars in the process. Over 76,000 accounts have registered stealth keys to enable privacy preserving payments through Umbra. Despite this growth, Umbra remains a grant funded public good project made possible by the community.

In 2024, we led a community effort to develop a Stealth Address EIP, so that Umbra can remain an open, public goods protocol. Both EIPs are now finalized, and we are working to drive adoption of this standard across the ecosystem.

What's Next

We are grateful to our many supporters who have enabled us to get this far. There's still lot's more work to do!

We believe there is so much more we can do to make Umbra an even more powerful privacy tool in the Ethereum ecosystem. In the year ahead, we're focused on continuing to improve Umbra through new network deployments, performance improvements, and host of small UX improvements and features.

With the stealth address standardization effort completed, we've begun work on Umbra v2. It will be the flagship implementation built on top of this new standard, and it will include a host of new features and capabilities making it significantly more flexible and powerful than Umbra v1. We're excited to share details about our v2 architecture soon!

Umbra has never raised VC funding or launched a token. We rely on grant funding to make this project possible. Thank you for your support of privacy technology in the Ethereum ecosystem.