Please describe your proposed solution

Subbit.xyz : Cardano's featherweight L2

+ Security guarantees of the L1

+ Instant settlement

+ Absolutely tiny footprint

The user journey goes like:

1. Alice runs a service and wants it to be financially sustainable
2. Bob wants to use Alice's service
3. Alice sees Bob's account on-chain, and is happy to serve Bob
4. All the while Bob is supplying Alice IOUs, Alice serves his request, all is well
5. When Alice needs to pay her server bills, she submits the latest set of IOUs (from Bob, Charlie, …) to the L1
6. When Bob wants, he can close the account
7. After the final claim or some pre-agreed time frame, Bob can withdraw the remaining funds

Components:

+ Smart contract

+ Tx-builders

+ Spec, SDK, & How-To docs on wrapping any existing service in subbit

+ Demo application

+ Hosted instance of demo

"… But why not hydra?!" we hear some of you ask.

Subbit is premised on the observation that most on-going service engagements are unidirectional two-party : someone provides a service, and someone consumes the service. And normally the consumer pays for it.

Subbit is an L2 that models this. Just this.

Because subbit is focused, it's featherweight. No need for persistent network connection. No mutli-sig. No need to port a plutus VM to a new device. A subbit account costs bytes of storage to the consumer and the provider. If the device can sign and send a message, it can run subbit.

Your arduino can run subbit. Your minimal spec cloud VM can run 100,000s of channels subbit. Reasoning about subbit is simple because subbit is simple.

Subbit is not a hydra replacement. They are both L2s, and that is the end of their similarities.

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

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

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

+ Number of subbit accounts live

+ Volume transferred

+ Number product integrations

+ Derivatives such as pay with native assets

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?

Phd in geometric topology. Former Data scientist/ ML eng.

10 years dev. 2.5 years on Cardano. Runs artisan dapp dev house, Kompact.io.

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

Milestone 1: Output: Smart contract with fuzz tests.

Criteria: Does it build? Tests succeed?

Evidence: Repo with working code and build instructions.

Milestone 2: Output: Repo with Tx building code.

Criteria: Code runs.

Evidence: Tx hashes of all types of tx, verifiable on preview testnet.

Milestone 3: Output: Minimal application example: mr-wolf

Criteria: Code builds and runs. Tests pass. Benchmark available.

Evidence: Repo with working code and build instructions.

Milestone 4: Output: Spec, SDK, and a How-To guide on wrapping an existing service.

Criteria: Is it clear and coherent?

Evidence: Link to github pages docs site, mr-wolf application providing a minimal example.

Milestone 5: Output: A second example: Kupmios (Kupo+Ogmios).

Criteria: Code builds and runs. Tests pass. Benchmark available.

Evidence: Repo with working code and build instructions.

Final Milestone: Output: Hosted Kupmios demo.

Criteria: Can a client connect? Performs a full subbit account lifecycle?

Evidence: Endpoint available. A way to verify a full subbit lifecycle.

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

Just waalge

Please provide a cost breakdown of the proposed work and resources

M1: 40h

M2: 40h

M3: 30h

M4: 50h

M5: 40h

M6: 20h

Buffer: 20h

Total hours: 240h

Server costs for 12 months: 1200$

Potentially less via a partnership

240 * 80$ + 1200$ = 20400

20400 * 2.4 = 48960 Ada

No dependencies.

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

Definitely.