Deflationary disclosure - add-token feature on Matcha

Deflationary tokens currently do not show the proper estimate on Matcha. Is there a way for Matcha to grab previous blockchain transactions to detect deflation and give some kind of additional disclaimer or warning?

For example, $ROT burns 2.5% per transaction for MAGGOT. The UI tells me I’m getting 597 tokens, but I end up with 582. If users don’t know this, they may seek support and drain manhours for community engagement staff.

Minimal suggestion: tooltip to show estimated deflation per transaction
Ideal suggestion: Show deflation and result (do they get another token, or is it burned? what happens with the token?)

Deflationary mechanisms may become more popular and thus disclosure is important to avoid confusion for new users.

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Update: I spoke to Theo and he stated this feature is something the team is considering, no commitment or timeline provided.

Thank you Theo for your engagement!

Deflationary Tokens - Update:

I noticed slippage is maximum 5% per TX on Matcha for unverified tokens.

I did some test transactions:


SAV3 usually requires 8-9% slippage, and you can see the transaction buys 490 SAV3 and applies the 8.3% tax.

Questions: Does the formula calculate after the tax? On Uniswap, the slippage includes the tax.

Test 2:

12% tax per transaction. I inputted to buy 363 RFCTR and it said .0384 ETH will be spent. 0.0403 was actually spent (I believe the marginal difference is a back end rebase transaction distributing 12% of my transaction to holders)

Questions: I would encourage the team to do further testing on this type of token, since the UI does not disclose that there is an additional tax. The UI discloses general safety issues with tokens, but may need another query to determine deflationary measures.

I’d like to see a tooltip that has a back end query to previous tx to alert the user to any tax, and then separate that from expected slippage. Currently this feature is not available on Uniswap.

Suggestion for easiest integration:

This contract, for example, has a 1% tax per transaction.

They have enough volume to warrant review/add as a sponsored token on Matcha. Though they’re a competitor to projects I work on, I’d advocate this as a test case for deflationary disclosure since they qualify and have the volume. The 1% tax, sent to all holders each transaction via a rebase mechanic, would be easy to code into the UI and disclose as a starting point to onboard more tokens trending in deflationary directions.


I’m hoping to connect with the Matcha team to see if we can integrate RFI into the platform. I understand it’s an aggregated DEX - I’d love to speak more about requirements & how we can work together on the integration.

Please contact me here or at the following:

TG: @El_Crypto_Chapo

Thank you!

I go to swap my $ROT balance (0xd04785c4d8195e4a54d9dec3a9043872875ae9e2)


Price impact on Uniswap shows 6%+

I tried to reduce the amount by 10% but it still didn’t work.

TX went through on Uni. I used 10% slip. Max on Matcha is 5%.