nft_getAsset (Mythos NFT helper)
Retrieve Mythos NFT metadata, ownership, and marketplace pricing with standard Substrate RPC calls.
Mythos nodes do not expose a bespoke nft_getAsset RPC endpoint. Instead, combine the core Substrate methods state_getStorage and state_getKeysPaged (or higher level SDK calls) to read pallet_nfts storage and any marketplace listings. The examples below were captured on 3 Oct 2025 using the public endpoint https://api-mythos-archive.n.dwellir.com/YOUR_API_KEY.
Storage layout
| Storage entry | Purpose |
|---|---|
Nfts::Item(collectionId, itemId) | Owner, approvals, and deposit metadata for a specific NFT |
Nfts::Collection(collectionId) | Collection owner, minted counts, and attribute flags |
Marketplace::Asks(collectionId, itemId) | Active fixed-price listings (seller, price, expiry, escrow agent) |
Example: collection 2783, item 21
The following request reads Nfts::Item(2783, 21)—an NFT owned by 0x6f5e2dee7182143c809c6606f5c50ffb0cc7f4dd. The storage key was generated with api.query.nfts.item.key(2783, 21).
curl https://api-mythos-archive.n.dwellir.com/YOUR_API_KEY -H "Content-Type: application/json" -d '{
"jsonrpc": "2.0",
"method": "state_getStorage",
"params": [
"0xe8d49389c2e23e152fdd6364daadd2cce6636c7091b616c035068763633f33e2001352fa0fbf816218e34d69e86c8929df0a0000000000000000000000000000000000000000000000000000000000000af23d6fc2fce072a34ac19d2a5553b615000000000000000000000000000000"
],
"id": 11
}'Sample response
{
"jsonrpc": "2.0",
"id": 11,
"result": "0x6f5e2dee7182143c809c6606f5c50ffb0cc7f4dd00b78aec3ecc939755abfe78aba306f2bf428da63700000000000000000000000000000000"
}Decoding the SCALE payload as ItemDetails yields:
owner = 0x6f5e2dee7182143c809c6606f5c50ffb0cc7f4dddeposit.account = 0xb78aec3ecc939755abfe78aba306f2bf428da637deposit.amount = 0approvals = []
JavaScript helper
import { ApiPromise, WsProvider } from '@polkadot/api';
async function loadItem(collectionId: number, itemId: number) {
const api = await ApiPromise.create({ provider: new WsProvider('wss://api-mythos-archive.n.dwellir.com/YOUR_API_KEY') });
const item = await api.query.nfts.item(collectionId, itemId);
if (item.isNone) {
throw new Error('Item not found');
}
const details = item.unwrap();
console.log(`Owner: ${details.owner.toHex()}`);
console.log(`Deposit account: ${details.deposit.account.toHex()}`);
}
loadItem(2783, 21).catch(console.error);Joining marketplace data
Marketplace::Asks(2783, 21) contains the active listing for the same asset. The seller, price, and escrow agent are combined in a single SCALE payload.
curl https://api-mythos-archive.n.dwellir.com/YOUR_API_KEY -H "Content-Type: application/json" -d '{
"jsonrpc": "2.0",
"method": "state_getStorage",
"params": [
"0xb8f32c9f36429933d924999a1b87423f9be4002e98967383af7072a5f12bde48001352fa0fbf816218e34d69e86c8929df0a0000000000000000000000000000000000000000000000000000000000000af23d6fc2fce072a34ac19d2a5553b615000000000000000000000000000000"
],
"id": 12
}'Sample response
{
"jsonrpc": "2.0",
"id": 12,
"result": "0x6f5e2dee7182143c809c6606f5c50ffb0cc7f4dd000050efe2d6e41a1b0000000000000000d8c32cbb030000000058c51ff571cb030000000000000001dbe1638c2063432d6923e30d2f4406e2e91e767f"
}Decoding yields:
seller = 0x6f5e2dee7182143c809c6606f5c50ffb0cc7f4ddprice = 500000000000000000000plancks (0.500000000000000000 MYTH)fee = 70000000000000000000plancks (0.070000000000000000 MYTH)expiration = 4102444800000(Unix millis; effectively no expiry)escrow_agent = 0xdbe1638c2063432d6923e30d2f4406e2e91e767f
Rust (dynamic API)
use subxt::{dynamic::Value, OnlineClient, config::substrate::SubstrateConfig};
#[tokio::main]
async fn main() -> subxt::Result<()> {
let api = OnlineClient::<SubstrateConfig>::from_url("wss://api-mythos-archive.n.dwellir.com/YOUR_API_KEY").await?;
let item: Value = api
.storage()
.at(None)
.await?
.fetch(&Value::from_parts("Nfts", "Item", (2783u32, 21u128)))?
.expect("item exists");
println!("Item details: {item:?}");
let ask: Value = api
.storage()
.at(None)
.await?
.fetch(&Value::from_parts("Marketplace", "Asks", (2783u32, 21u128)))?
.expect("ask exists");
println!("Listing: {ask:?}");
Ok(())
}Best practices
- Cache decoded JSON in your asset or marketplace service; most fields only change on ownership transfers or new listings.
- Use
state_getKeysPagedonNfts::Itemto backfill entire collections without overloading the RPC node (e.g., batches of 256 keys). - Always confirm a listing exists before letting players buy—prices may be updated or removed between UI refreshes and submission time.