Contribution period: 2023/03/01 - 2023/04/14
Requested tip: [Updated] 1,640,000 HDX ($7,400 USD) 4,100,000 HDX (~$18,500 USD) to 7KnNvPwcYg7sAMgp9SK3knZavx2PkK9AJ1UQAdE3PhrmCWZa
Time spent: 185 hours
Summary: 1-click swaps to ANY Omnipool token from Moonbeam, Astar, Polkadot (or vice versa)

Our ask

We request 1,640,000 HDX ($7,400 USD) 4,100,000 HDX (~$18,500 USD) for 185 hours of development work, at a rate of $40 $100 USD/hr and using the current HDX price of $0.00451 USD. We did not find any comparable technical development HydraDX tip requests, so we are referencing (and discounting) the $125 USD/hr figure cited in similar Polkadot treasury requests. Please see https://polkadot.polkassembly.io/treasury/210, https://polkadot.polkassembly.io/treasury/223, and https://polkadot.polkassembly.io/treasury/199 for reference.

Context: PrivaDEX is the only cross-chain DEX aggregator on Polkadot

For context, PrivaDEX is the only cross-chain DEX aggregator on Polkadot: it is live at https://app.privadex.xyz. Before integrating HydraDX Omnipool, we only supported EVM DEXes on Moonbeam and Astar. HydraDX Omnipool is our first Substrate DEX. Now, users can swap from/to any Omnipool token to/from any token on Moonbeam, Astar, and Polkadot relay. More concretely, a DOT holder can swap their relay chain DOT into HydraDX HDX in one click - a use case we have already seen Omnipool LPs use.

About us: We have been developing in Polkadot for the past 7 months. We received a level 3 Web3 grant to build an MVP DEX aggregator (see the proposal at https://github.com/w3f/Grants-Program/blob/master/applications/PrivaDEX_aggregator.md), which we successfully delivered in January.

Summary: 1-click swaps to ANY Omnipool token from Moonbeam, Astar, Polkadot (or vice versa)

All in all, we put in 185 hours of development work over the course of 3.5 weeks. We spent most of March focused on this integration; we spoke to several core members of the HydraDX team in early March, who gave us advice and pointed us to development resources. We released Omnipool support in early April (see our April 4 announcement at https://twitter.com/doprivadex/status/1643045167098925056). When HydraDX ambassadors notified us that ZTG, iBTC, and USDT were added to Omnipool on April 13, we added support into our aggregator within 24 hours (see our April 14 announcement at https://twitter.com/doprivadex/status/1646688608458534912).

Quantifying Technical Work Done

Lines of code are a notoriously bad way of quantifying work, but for what it’s worth, we added over 3700 lines to our code base. Below are a few of the major technical components we added:

1. Index the Omnipool so we can compute price and swap quotes in real-time. Due to the interfacing with LRNA, Omnipool’s quote formulas are different from the Uniswap equations we were familiar with coming from Moonbeam and Astar EVM DEXes.
2. Add HydraDX-specific constants and configurations to our static chain and DEX registries. These are factored into everything from estimated fees for our quote estimates, to extrinsic encoding mechanism for our execution engine
3. Support for constructing HydraDX-specific pallet calls: balance and token transfer, XCM transfer, Omnipool send and buy
4. Support for detecting and parsing completed HydraDX extrinsics for each of the items in (3) above - e.g. how much of a token was sold or bought or transferred. Every Polkadot chain produces a slightly different set of events that has unique parsing logic.
5. Supporting a Substrate extrinsic as the initial and final transfer from/to the user. Earlier, because we only supported ERC20 and XC20 tokens on Moonbeam and Astar, we only supported ‘Eth’ sends and ERC20 transfers
6. Deduplication logic of a transfer extrinsic from the user. This is a security measure to ensure one user transaction kicks off exactly one flow. Note that earlier deduplication logic was simpler because Ethereum transaction hashes are known prior to sending, while Substrate extrinsic unique identifiers (block + index) are only known after block inclusion (extrinsic hashes are not necessarily unique)
7. Add configurable extrinsic signature encoding because HydraDX signers are encoded as a plain public key instead of as a MultiAddress, which is the standard for Polkadot relay and Astar

Update: 2023-04-26

Thanks for the community responses below and in particular for those who voiced appreciation for the work we've put into this! We realize that the initial request is too high given current market conditions and lack of cross-chain trading traffic. We have thus slashed our initial request to 40% of the original one. I'd love to reopen feedback on our tip request.