Decoding custom smart contract types in dApp/front-end with SDK v13 – missing or outdated example

[eduardoPauloPanstein]

Hey team,

I'm working on a real-world use case and wanted to share a gap I found in the current documentation, especially for developers following the recommended dApp setup.

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🔍 Summary of the Problem

1. I learned how to create smart contracts and successfully deployed a custom one on the devnet. Everything worked smoothly up to this point.
2. To build a frontend for users to interact with the contract, I followed the usual path — using the template-dapp as recommended (it includes the ping-pong examples).
3. I removed the ping-pong logic and adapted it to my contract, which returns a custom type that I need to decode.
4. For that, I referred to the v13 SDK JS cookbook to follow best practices and avoid using the now outdated SmartContract.createQuery() method (still present in the template-dapp).
5. However, I hit some issues right away:
   • The code sample in the cookbook uses apiNetworkProvider, which isn’t defined in the template-dapp context.
   • After digging, I found it is defined earlier in the cookbook, but that setup isn’t compatible with the template-dapp structure. I had to reverse-engineer how to plug it in correctly.
6. Once I got past that, I reached the main blocker: the example for decoding a custom type simply does not work. I tried both getCustomType() and getStruct() with no success, and couldn’t find a working example that bridges the gap between template-dapp and decoding with ABI in the frontend. Even after reading through SDK v14 resources and cross-checking with older tutorials, I couldn't get the decoding to work from the frontend as documented. I eventually made it work another way — but it took hours of trial and error.

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❗ Why This Matters

This flow is the first thing new developers will try when building on MultiversX with custom logic. The experience should be smooth — especially when the recommended template and cookbooks don't align anymore.

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📌 Priority

Medium-High — This blocks progress for developers building real apps with custom return types.

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🙌 Offer to Help

Happy to:

• Share my repo with a working version
• Provide code snippets
• Record a short video (~4 minutes) showing exactly where the friction
• Or even jump on a call

Let’s improve this together! 🚀

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Tags: documentation, sdk-js, v13, v14, abi, custom-types, frontend, template-dapp