Patract is developing development tools and services for Polkadot’s Wasm contract technology. With the support of Polkadot Treasury, we have completed the development, report, and external review of [Himalia](https://kusama.polkassembly.io/post/428) and [Ask!](https://kusama.polkassembly.io/post/1059). However, in the past six to twelve months, the underlying technology of Wasm contracts led by Parity has undergone tremendous breaking changes, so we continued to contribute our developers for long-term maintenance. Among them, the function changes of [Pallet-Contracts](https://github.com/paritytech/substrate/projects/6#column-5694481) and [ink!](https://github.com/paritytech/ink) mainly include

- **Change of Pallet-contracts**
    - Refactors
        - [PR#9838](https://github.com/paritytech/substrate/pull/9838) contracts: Refactor dispatchables
        - [PR#8604](https://github.com/paritytech/substrate/pull/8604) contracts: Refactor the exec module
        - [PR#9669](https://github.com/paritytech/substrate/pull/9669) remove rent contracts: Remove state rent
    - update about host_func
        - [PR#10366](https://github.com/paritytech/substrate/pull/10366) Stabilize "seal1" seal_call
        - [PR#9609](https://github.com/paritytech/substrate/issues/9609) Contracts pallet - Add support for recovering public key from elliptic curve signatures (ECDSA) 
    - update about debug_message 
        - [PR#9550](https://github.com/paritytech/substrate/pull/9550) Stabilize seal_debug_message
        - [PR#9051](https://github.com/paritytech/substrate/issues/9051) seal_debug_message not showing up in process output
    - update about wasm executor
        - [PR#10173](https://github.com/paritytech/substrate/pull/10173) Refactor sp-sandbox; make sure both sandbox executors are always tested
        - [PR#10268](https://github.com/paritytech/substrate/pull/10268) Forward wasmer-sandbox feature to sp-sandbox
        - [PR#5920](https://github.com/paritytech/substrate/pull/5920) Integrate Wasmer into Substrate sandbox environment
- **Change of ink!**
    - [PR#792](https://github.com/paritytech/ink/pull/792) Implement seal_debug_message
    - [PR#914](https://github.com/paritytech/ink/pull/914) Implemented ECDSA recover function.
    - [PR#903](https://github.com/paritytech/ink/pull/903) Cleanup metadata codegen slightly
    - [PR#845](https://github.com/paritytech/ink/pull/845) Update to scale-info 1.0, introduce metadata format versioning
    - [PR#665](https://github.com/paritytech/ink/pull/665) Implement new trait definition codegen rocket
    - [PR#997](https://github.com/paritytech/ink/pull/977) Use edition 2021

In addition, we paid a lot of cloud server and bandwidth costs for API service [Elara](https://elara.patract.io). The following is a summary of the maintenance work and cost of each product in the past year:

### Himalia (12 months)

Himalia is our Wasm contract multi-language SDK, divided into Go/Python version. More than a year ago, we completed the development of [version 0.2](https://kusama.polkassembly.io/post/428). After that, the maintenance work of the Github repo are as follows:

- [PatractGo](https://github.com/patractlabs/go-patract/):
    - Submitted [16 Commits](https://github.com/patractlabs/go-patract/commits/master).
    - Updated version to support metadata14 format modification
    - Update all test cases to support the latest version of ink!
    - Add erc721 example
    - Add delegator test cases for contract mutual calls
    - Fix other discovered problems
- [PatractPy](https://github.com/patractlabs/py-patract):
    - Added [6 Commits](https://github.com/patractlabs/py-patract/commits/master).
    - Updated version to support metadata14 format modification
    - Update all test cases to support the latest version of ink!

The maintenance costs are:

- 1 maintainer * monthly salary $200 * duration 12 months = $2400

### Elara for Kusama (12 months), Statemine (7 months), Westend (8 months), Westmint (7 months)

Elara is a node API service similar to Ethereum Infura. By building a middleware service layer, we can provide large number of users to visit by a small number of nodes. More than a year ago, we completed the development of [version 0.2](https://polkadot.polkassembly.io/post/566). After that, the main maintenance cost is from maintainer and cloud service.

maintenance cost ($74980) :

- 1 maintainer * monthly salary $500 * duration 12 months = $6000
- The total cost of Alibaba Cloud service in Singapore is  $68980 (434579 CNY), the details are as follows:
    * The unit price of each service is: ![](https://i.imgur.com/AvJAO8g.png)
    * Resources and costs actually consumed by each network：![](https://i.imgur.com/KNMXpNB.png)
    * This is the screenshot of the Alibaba Cloud bill, the total cost is 805773 CNY, from which the Polkadot/ Statemint services should be paid by the Polkadot Treasury are 204969 CNY, and the Kusama/ Statemine/ Westend/ Westmint services should be paid by the Kusama Treasury are 434579 CNY, the rest are for other community chains. ![](https://i.imgur.com/sTdr23e.png)
    * This is the screenshot of the Elara website statistics, total is 97352 GB / 6.06 Billion Requests, from which the traffic for Polkadot/Statemint is 18693 GB, for Kusama/ Statemine/ Westend/ Westmint is 77572 GB, the rest are for other community chains. ![](https://i.imgur.com/zpmA37M.png)

### Summary (2021)

$2400 (Himalia) + $6000 (Elara maintainer) + $68980 (Elara cloud) = $77380 / Monthly avg price of KSM $330 = 234 KSM

- Patract is developing tools and services for Polkadot's contract technology.
- They have made changes to the Pallet-Contracts and ink! functions.
- They have been maintaining the Himalia SDK for 12 months, with updates and fixes.
- They have also been maintaining the Elara API service for Kusama, Statemine, Westend, and Westmint for 12 months.
- The total cost of maintenance for the year is 234 KSM.

#1205 Patract Labs' maintenance cost for Kusama of 2021

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