Decentralized Futures Proposal: SLAP - Simple Layer for Accelerated Payments

We’re excited to introduce SLAP: a fast blockchain-based layer for private stablecoin payments, specifically designed for the Polkadot ecosystem. SLAP will integrate with new and existing payment methods, to allow retail users and businesses to benefit from the innovations brought by the blockchain technology. Interaction with the Polkadot ecosystem will benefit both parties, as SLAP is bringing a new wave of users from more traditional backgrounds, which will use parachain services through cross-chain dApps.

We believe in the power of blockchain to transform the way people interact with money, but recognize the challenges of regular people when it comes to crypto jargon and complex workflows, unfriendly interfaces and wallets, or the inconvenience of paying using a volatile asset.
Moreover, most non-crypto people have concerns regarding public balances, being more willing to disclose them only with the rightful authorities for tax declarations.

What sets SLAP apart from other fast-finality blockchains, like Solana or Arbitrum?

  • Adoption through integration with existing payment solutions, targeting real world businesses and their customers as primary users, which can benefit of the innovations brought by web3.
  • SLAP provides privacy-preserving transactions, with a custom zero-knowledge based protocol that obfuscates balances and transferred amounts, while introducing optional disclosure to allow legal compliance.
  • Its Polkadot-oriented design: SLAP was conceived to make use of parachains for multiple services, like decentralized exchanges or smart contracts. We will build libraries and infrastructure to facilitate cross-chain workflows, while keeping the core of our product lightweight and focused on payments.

This is a high level sketch of how SLAP’s architecture will look like:

As the diagram shows, applications and physical devices will use Ramping Systems to move liquidity on-chain, and will delegate interaction with cross-chain data and logic to our APIs.

Technical constraints make the parachain model unsuitable for a fast-finality blockchain. Therefore, SLAP will be a solo chain, which will access the Polkadot ecosystem through a parachain able to handle bridge logic. The current candidate is Pop Network (please support them as well :heart:). Would that not be possible, then we will consider other parachains or having our own. Communication between SLAP and said parachain will be managed by a Trustless Bridge.

The last components of our architecture are Aggregators, which leverage the properties of recursive zero-knowledge proofs to increase transaction throughput.

SLAP goes beyond basic transactions. We will offer:

  • DApps for simplified access, for example for cross-chain transfers or staking.
  • Partnerships for growth, including but not limited to Polkadot projects.
  • Consulting services: our expertise will be available to any entity that wants to leverage our payment layer.

Anyone, anywhere, should be able to send and receive money quickly and easily, and we invite you to join us in this exciting journey as we strive to build SLAP to make that vision a reality.


SLAP’s integration with existing payment solutions, emphasis on user-friendly interfaces, and commitment to privacy-preserving transactions make it a standout proposal. Leveraging the Polkadot ecosystem for cross-chain functionality adds further versatility, promising to revolutionize the way we interact with money. I’m eager to see SLAP’s impact unfold and how contributes to the growth of the blockchain ecosystem. Count me in as a supporter of this exciting journey!

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It seems like a really interesting project, I’m curious to see future applications and the feedback it will bring to polkadot Well done Muraca and team!

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Hey @muraca

If you would include XCM “readyness” in your design you will be probably in a very good position for interaction within the Polkadot ecosystem. This should also save you lots of work regarding “build libraries and infrastructure”.

Hey @PieWol thanks for your kind suggestion.
I’m quite familiar with XCM as a Polkadot Blockchain Academy graduate, and also thanks to my previous work experience. We will definitely use XCM for cross-chain messaging, however this is not in contradiction to what I wrote in the post.
We want to provide a simple set of operations in our APIs, allowing the application developer to ignore how the messages are formed and transmitted to the other networks: they will only need to state where they want to move some token, and be notified when the process has been completed.
Hence the facilitation of cross-chain workflows.

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Hi @muraca,
We are quite intrigued with your proposal :grinning:

Some questions that will help to clarify our understanding of it:

  1. Are you planning to issue your own stablecoin?
  2. How does it compare to Aleph Zero (speed, privacy, programmability, etc.)?
  3. Why not integrate your chain with Bridge Hub?
  4. Which ramps are you planning to integrate with and why they would be interested?
  5. Have you considered channeling tokenized deposits as an alternative to stablecoins (will be hard to engage a bank in but not sure if it is harder than onboarding/issuing stables)?

It’s an amazing problem space and we’re keen to know more!

Hello @sodazone, glad to hear you want to know more, and thanks for your questions.

  1. Are you planning to issue your own stablecoin?

Not at the moment, we’d rather partner with some well-established provider to use stablecoins that people are already familiar with and trust.

  1. How does it compare to Aleph Zero (speed, privacy, programmability, etc.)?

We are currently planning to use the AlephBFT finality gadget to achieve finality in 1 second.

While programmability is not comparable, as our chain will initially only handle payments while delegating smart contract logic to parachains, SLAP will natively offer private transactions that, by taking advantage of zero knowledge proofs, will enable users to prove their financial situation for legal compliance.
We are already exploring some possibilities, as we are currently working on Tux0, a private currency module for Tuxedo, founded by a Web3 Foundation Grant.

  1. Why not integrate your chain with Bridge Hub?

The truth is we have so many options for a bridge, but not enough time for a deep dive to determine what’s the best option right now. Something that involves Bridge Hub can be considered, as much as we can consider other candidates like Hyperbridge or Composable.

  1. Which ramps are you planning to integrate with and why they would be interested?

That’s a good question, especially the second part.

SLAP aims to be used by multiple payment systems, targeting users all over the world, and we believe it will become more attractive for ramping systems as more services will start to support it.

We hope we can find a player that believes in our vision, and is willing to offer more attractive exchange rates in return for integration in our customers’ applications. However, we can see this play out in many different ways, including a fair competition between multiple ramping systems, or payment systems offering this service to their customers themselves.

  1. Have you considered channeling tokenized deposits as an alternative to stablecoins (will be hard to engage a bank in but not sure if it is harder than onboarding/issuing stables)?

Thanks for the tip!
After a first read on the subject, it looks like they might fit our use case, but with many potential caveats. As you said, a partnership with a bank might be hard, however non-crypto users could be more willing to trust banks instead of a stablecoin provider. We will consider this.

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The inception of this project came about over a discussion over building a fast network on Polkadot - what that would look like and what would take to build it.

First good real use case for a fast Polkadot network would be payments. We are already lagging behind our competitors - look at Solana: sub-400ms payments.

Slap is framing itself to be “the payment network of Polkadot”. This team is a perfect fit for this project as their previous work with UTXO’s and ZK via web3 grants will fit nicely to build a first-of-its-kind “only on Polkadot” solution with privacy-preserving transactions with optional disclosure.

Applying for funding from the DF Program has required the team to put a “product hat” on and I am proud of the work that they have done in this direction, as a technical partner for the team, I have seen the internals of their work for the SLAP proposal.

My push is for the team to do consulting with web2/3 payment solution providers to gain deeper knowledge into the space, iterate the platform to be the premier crypto payment solution of choice in Web3.

Fast payments is the first step. From there, payment solution providers can build permissionless use cases on Polkadot via Pop Network smart contracts. Pop Network has a Pop API which will have useful primitives including cross-chain primitives to make developing interopable contracts accessible to smart contract developers. As the SLAP team mentioned, payments is not a one person job, you have multiple audiences involved: customer, merchant, payment solution provider, and POS. Cutting out the likes of VISA/Mastercard in favor of crypto, creating more efficient fee distribution amongst the players involves, and incentives are all possible.

SLAP aims to be the infrastructure platform for payments. If we all help on-ramp web2 payment solutions to SLAP, this will benefit the community as a whole, as currently there are many web2 payment solution providers that would like to offer crypto payments. We can disrupt our competitors be offering a more compelling package.


It looks promising, there’s a real need for project bridging between web2/web3 and payment is without any doubt a big problem with a need of a solution. Let’s see where it goes!

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