Please describe your proposed solution

Subbit.xyz is an L2 that:

+ shares the security guarantees of the L1

+ has instant settlement and unbounded TPS

+ is simple to use, build on, and reason about

+ and all with an absolutely tiny footprint.

It is an L2 optimized to be integrated into subscription services.

The project is in two parts:

+ Subbit.xyz - validators, tx-builders, documented SDK

+ A real world application using Subbit.xyz : Orcfax’s payment solution.

Let's describe how Subbit.xyz works via a user journey of a dApp developer/user that requires an oracle service.

Bob's dApp requires oracle services and chooses Orcfax as the service provider.

Orcfax has its services wrapped up with Subbit.xyz payment channels enabled.

1. Bob wants to use Orcfax's service. He opens an account with Orcfax. In doing so he locks some funds at the subbit smart contract.
2. Orcfax verifies the account and sees Bob’s account balance, and begins providing service to Bob.
3. With each request Bob includes an incremental guarantee of payment Orcfax checks these are correct and doesn’t exceed the locked funds.
4. When Orcfax needs to pay their server bills, they submit a batch of these latest guarantees (from Bob but also Charlie, etc …) to the L1. Orcfax is paid exactly what they are owed by each of their subscribers.
5. Whenever Bob wants, he can close the account. Orcfax has a time window to make one final claim of the outstanding balance.
6. After this final claim or the end of the time window, Bob can withdraw the remaining funds.

Bob is always in control of his balance. He knows exactly how much he owes Orcfax, and knows that the remainder of the balance is safely his. No nasty surprises.

Components:

+ Smart contract

+ Tx-builders

+ SDK with documentation

+ How-To docs on wrapping any existing service in Subbit.xyz

+ Real world application to Orcfax's subscription service including user facing interfaces.

Please define the positive impact your project will have on the wider Cardano community

The success of Subbit.xyz will open a whole new tranche of business models to be built in, on, and around Cardano and beyond.

The integration with Orcfax will:

+ streamline development and the running of dApps requiring oracle services

+ provide validation for the design decisions of Subbit.xyz.

+ be a blueprint for how any subscription service, not just Cardano native dApps, can utilize Subbit.xyz to provide secure, instant, and virtually feeless payments easily within their product.

We will measure the success of the project in the following ways

+ Orcfax customer count and volume.

+ Number of projects expressing interest (Letters of Intent-esque) in integrations.

+ Number of projects using Subbit.xyz.

+ Number of Subbit.xyz channels, txs, and volume.

The milestones of the project are framed to maximize these stats.

For example they include a documented SDK and on-boarding workshops.

What is your capability to deliver your project with high levels of trust and accountability? How do you intend to validate if your approach is feasible?

Project lead (waalge) is Math PhD. Formerly ML engineer and full-stack dev. DApp developer since Alonzo HF. Aiken contributor, particularly the nix maintenance and fuzz lib.

On feasibility: A version of the spec and SC is already available: https://github.com/kompact-io/subbit-xyz .

(The SC will be rewritten in Aiken v1 and use Plutus v3 during the course of this project.)

What are the key milestones you need to achieve in order to complete your project successfully?

Milestone 1: Specs and SCs

Output: Spec. Smart contract with fuzz tests. Benchmarks

Criteria: SC aligns with spec. SC builds. Tests succeed. Benchmarks run.

Evidence: Public GH Repo. Spec viewable on github and website. Clear build instructions and reproducible benchmarks. A short post giving commentary and interpreting the benchmark numbers (viewable on the repo or site).

Milestone 2: Tx builders

Output: Tx building code and tests.

Criteria: Feature aligns with Spec. Full test coverage. Tests succeed.

Evidence: Repo contains Tx builders. Tests run. A short document of annotated tx hashes demonstrating full life-cycle of protocol.

Milestone 3: SDK

Output: SDK. How-To guide on wrapping an existing service with Subbit.xyz.

Criteria: Complete SDK, preferably in at least two popular languages (subject to resourcing).

Evidence: Repo contains SDK. How-To guide and developer docs on website. Executable examples run following build instructions.

Milestone 4: Real World Application: Orcfax Payment System

Output: Orcfax integration: payment channels for subscription service.

Criteria: An integrating dApp can track, and manage accounts via interface. Orcfax can track and manage the customer base. Payments being handled.

Evidence: Screenshots of interface. Video demo. Testimonial from external beta testers.

Milestone 5: Open Sourcing the RWA

Output: Open sourcing the Orcfax payment system.

(This is so much more than simply slapping on license and changing the repo's privacy settings.)

Criteria: Clear build instructions with tests succeeding. Extensive documentation coverage. Guide(s) for self on-boarding. ADRs explaining design decisions where appropriate.

Evidence: Public GH repo with working code and build instructions. A blog post style explanation of the software, written for a general audience. Either the same piece or a modified version for those wishing to perform their own integration.

Final Milestone: Alignment and Outreach

Output: Project coherence and expanded awareness/ and utilization

Criteria:

+ Review all previous output and code to realign any drift (eg stale docs _etc_).

+ Address GH issues, follow up on inquiries of interest, provide integration support.

+ Actively promoting the potential of Subbit.xyz to the Cardano community and beyond including at least two public presentations / workshops.

Evidence:

+ Evidence, including participant feedback, of presentations/ workshops.

+ Resolved gh issues and/or engagement on gh discussions.

+ A blog post debrief of the project to date, including a list of entities who have been contacted and/or expressed interest (anonymised on request), and laying out next steps.

Who is in the project team and what are their roles?

+ waalge, Kompact.io - Project lead. Dev for: SC, tx-builders, SDK, documentation

+ gabriel, Orcfax - Frontend aspects.

+ Christian Koch - Integration lead - Christian is an analyst, researcher and information systems professional who holds a Masters Degree in Archival Science with a focus on blockchain technology. Christian serves as the primary liaison between the development team, Orcfax clients and our community management team.

<https://www.linkedin.com/in/christian-mk/>

Please provide a cost breakdown of the proposed work and resources

M1: 80h

M2: 80h

M3: 60h

M4: 160h

M5: 60h

M6: 40h

Buffer: 20h

Total hours: 500h

500 x 100$ x 3 (₳/$)= 150000₳

No dependencies.

How does the cost of the project represent value for money for the Cardano ecosystem?

Subbit.xyz enables new business models to be built in, on, and around the Cardano ecosystem and beyond.

The integration of Subbit.xyz with Orcfax's service will demonstrate it on a production scale and provide a use-case from which other subscription-based providers can study, copy, and extend to their own needs.