---
# System prepended metadata

title: Appchain development with the Polkadot SDK

---

# Bounty Title + Description

**Bounty Title**

Appchain development with the Polkadot SDK

**Bounty Category**

Launch an MVP on Testnet or Mainnet

**Bounty Description**

The Polkadot SDK -- used by builders of over 50 layer-1 chains secured by Polkadot as well as other projects outside of Polkadot such as Madara (Starknet), Midnight (Cardano) and Polygon Avail -- is a powerful open source SDK that allows teams to build custom blockchains. For this bounty, we invite #BUIDLers to design and submit an appchain POC implementation using the Polkadot SDK.

# Bounty Awards + Prizes

## Prize Pool

**Prize Amount**

$4,000.00

**Number of Projects Awarded**

1 project

**Winner Breakdown**

The winning submission gets $4,000. If the judges find that no project is good enough to win, they'll be sure to explain why. The top 10 submissions will be considered for a fast track interview to the Polkadot Blockchain Academy and get support from Square One.

**Grant Program Opportunities**

Support from Square One (Substrate Builder's Program) and W3F grants.

# Bounty Guidance

**What is required to complete this prize?**


- **Code submission:** can be either your own clone of the extended parachain template with your custom pallets, a repository of the your custom pallets or a clone of an existing appchain you've extended
- **README file:** A description of the design of your appchain including the service it provides, it’s intended use and your plans to deploy it to production
- **Demo:** Short 2-minute video walking through your appchain logic and if possible, a demonstration of it using the Polkadot JS Apps UI
- **Bonus**: Teams who register their appchain to be deployed on the Rococo testnet or Kusama mainnet
- **Bonus**: Teams who demonstrate the use of XCM and use more than one appchain in their demo


**What does success look like? What are possible features that you are looking for?**

We're looking for a working proof of concept that could become deployed to Polkadot. Successful submissions are ones that:

- Provide a unique service to the Polkadot network and its existing parachains
- Identify and meet a need for Polkadot's end-users and ecosystem agents

Teams will have integrated their custom appchain pallets into a parachain template and will provide a clear demonstration of its use as a POC and plans for future development. For example, if a team decides to implement a new collective on the Collectives chain, the submission would include an appchain with the existing logic of the [Collectives chain](https://github.com/polkadot-fellows/runtimes/tree/main/system-parachains/collectives/collectives-polkadot), plus the new pallet(s) for the implementation of the proposed collective logic and its intended use. 

**What are the UI/UX Design Requirements**

The submission must include steps to run the appchain as part of a local testnet or in a Docker container along with clear instructions on the intended use of all callable functions the appchain exposes.

**How are you judging this bounty? What specific criteria do projects needs to be aware of?**

Your submission will be judged on the following:

* **Implementation and working node**: does your code work? how well does your implementation reflect your design goals? 
* **Novelty of idea**: how unique is your appchain? how is it adding value to Polkadot?
* **Business case**: what purpose does your appchain solve and do you have a good business case for it?


**What is the impact on your organization by a team working on this bounty?**

You'll be adding new services to the Polkadot network, adding new utility for users and exploring what Polkadot can offer for deploying your web3 application ideas.

# Bounty Resources

For a complete list of resources, check out [this dedicated page](https://github.com/sacha-l/polkadot-bounty-resources). Here are some resources that'll help you get started:

* Learn about Polkadot appchains: https://wiki.polkadot.network/docs/learn-parachains-index
* What Polkadot provides developers: https://paritytech.github.io/polkadot-sdk/master/polkadot_sdk_docs/polkadot_sdk/polkadot/
* Polkadot SDK reference documentation: https://paritytech.github.io/polkadot-sdk/master/polkadot_sdk_docs/reference_docs


**What are examples of use cases you are looking to solve?**

For this bounty we invite you to create a custom appchain. Though your submission may not be ready for production, this challenge seeks submissions of proof of concepts with have a clear idea for an appchain that can benefit the Polkadot ecosystem. These may get your creative juices flowing: 

* Recreate the logic of a popular L1 or L2 from another ecosystem
* Implement the logic of an existing dApp as it’s own appchain
* Extend the core logic of an existing system chain
