We definitely need lot more multichain service and tools and this is a great starting point.

Love the Talisman wallet =) -- We have built Polkaholic.io (https://polkaholic.io), a multi-chain Substrate blockchain explorer with APIs (https://docs.polkaholic.io) that has a lot of what you need, e.g. this API gets all the transaction history across chains
 https://api.polkaholic.io/account/121Rs6fKm8nguHnvPfG1Cq3ctFuNAVZGRmghwkJwHpKxKjbx?group=extrinsics
We are ready to power the Talisman wallet (+ site) with polkaholic.io APIs [and optimize out what you don't need for fastest query speed], and would like to optimize Polkaholic.io - Talisman connections with your help.  Email us { sourabh, michael }@colorfulnotion.com or chat with us on matrix.

That's a great UX improvement and Talisman is perhaps the right place to let this happen.

Interesting, I was just composing similar application https://github.com/Alzymologist/Grants-Program/blob/alzymologist-chainslug/applications/chainslug.md

Want to outsource backend to my team?

Let's chat. Feel free to reach out on Element or Twitter (links in my profile).

Transaction history across multiple chains is the missing link in this web3 ecosystem. I really look forward to seeing it come to life! <3

interested to see what you can do with this and your growing expertise in light clients - hopefully this doesn't get rid of too much pressure on parachain teams to learn about and make their networks more light client friendly and resilient, in lieu of just using indexed data provided by you everywhere :)

would be interesting to see if the approaches could complement each other instead of possibly contradicting each other. 

Really mint question Jam.

Our current line of thinking around light clients & indexers roughly follows the distinction:
- Leverage Light Clients to propagate actions to the network, poll important chain state (like a user's balance), and any other actions that require resilience and/or privacy. We can broadly think of this as information flowing "outbound" from a user.
- Leverage data indexers to provide rich & contextualised information for dapps/dashboards/etc, often coupled with data from off-chain sources (like fiat price feeds). We can broadly think of this as information flowing "inbound" to a user.

The proposal for cross-chain transaction history falls in the latter category and relies heavily on some indexers we'll construct, however it would be worth exploring how polling chain state from a light client could help verify the information retrieved from the indexers.

- Jonathan (Talisman)

[Talisman](https://talisman.xyz) is a community-owned wallet that enables users to “traverse the Paraverse” with ease. We believe in a future where everyone has freedom via true agency over their intentions and finances, and we believe that DotSama will bring this to fruition. 

For more on Talisman, please see the following talks from Polkadot Decoded 2022: Agyle’s [How Talisman is bringing multi-chain to the masses](https://www.youtube.com/watch?v=c7tZjVv70Jk), as well as Jonathan's [introduction to light clients in Talisman](https://www.youtube.com/watch?v=oaidhA5eL_8).

Today, because of its early stage of development and complex multi-chain architecture, both Polkadot and Kusama are changing rapidly and the user experience (UX) can be confusing for end users. It’s our goal to solve that using user experience design and storytelling. We abstract away the complexity of underlying implementation and provide a friendly user experience when using DotSama and a way to discover new applications and services available to end users, while keeping them safe and educated about the actions they are taking.

In this proposal, we are seeking to fund development of a cross-chain transaction history service for the benefit of users, parachains and applications. We believe this will be an advancement in usability and security for end users, as they will be able to more easily understand the actions they have taken across different parachains in DotSama. Parachains and applications that have a presence across multiple parachains will also have an easier way to show users their relevant actions.

We regularly gather customer feedback as we work to uncover difficulties customers have with Talisman and within DotSama. Here are what some users have told us about the need for better cross-chain transaction visibility:

- “Sometimes I don’t even know what assets I have. I do it the hard way, I have them all listed in p.js and I have to cycle through each of the projects to check my balances. When I check on sub.id everything loads, but sometimes locked tokens are missing. So I have to switch parachains, then visit each dapp to keep track.”
- "I would like to see my transaction history all in one place. This would be a huge help for example with my tax filings. Right now it's a real hassle."
- “I want to be able to see multichain assets across multiple parachains.”

We would love to get your feedback on the proposal. Please see the [full description here](https://docs.google.com/document/d/192asiQ13s4EAfXFFDFgKm_W3cqBVPPPxB5VNAig7keE/edit?usp=sharing).



#1152 Talisman Proposal: Cross-Chain Transaction History Service