Overview
Moralis Streams makes it easy to work with webhook payloads by providing parsed, structured data for common on-chain activity. The data Moralis parses for you depends on the chain.
On EVM, Moralis includes ready-to-use parsed sections such as:
- Transactions (
txs)
- Internal transactions (
txsInternal)
- ERC-20 transfers (
erc20Transfers)
- ERC-20 approvals (
erc20Approvals)
- NFT transfers (
nftTransfers)
- NFT approvals (
nftApprovals)
- Custom smart contract events, decoded using your ABI
This avoids manually decoding logs and building your own parsing pipeline.Example payload shape:{
"confirmed": false,
"chainId": "0x1",
"streamId": "uuid",
"tag": "string",
"retries": 0,
"block": { },
"logs": [],
"txs": [],
"txsInternal": [],
"erc20Transfers": [],
"erc20Approvals": [],
"nftTransfers": [],
"nftApprovals": { "ERC721": [], "ERC1155": [] }
}
On Bitcoin, each matched transaction comes with parsed UTXO-level fields:
- Block metadata — hash, height, timestamp, difficulty, merkle root, transaction count
- Transaction details —
txid, version, locktime, input/output counts
- Outputs (
vout) — value in BTC (not satoshis), scriptPubKey.address (recipient), scriptPubKey.type
- Inputs (
vin) — structural fields only (address and value are always null)
Output recipient addresses are already parsed and matched against your watched addresses (or addresses derived from a registered xpub) — no additional decoding required.vin entries do not include populated address or value fields, even with includeInputs: true. You can reliably detect inbound transfers; outflows require additional lookup. See Bitcoin Streams.Math.round(btc * 1e8). On Solana, every matched transaction comes with parsed snapshots that make instruction-level replay unnecessary for most use cases:
accountKeys — every account the transaction touches (signers, recipients, programs, reads, writes)instructions — top-level instructions with their programId and accountsinnerInstructions — nested instructions emitted via Cross-Program Invocations (CPIs)preTokenBalances / postTokenBalances — SPL token balance snapshots before and after the transaction
To compute SPL token deltas, subtract preTokenBalances from postTokenBalances for the accounts you care about — no instruction replay required.Solana addresses are base58 and case-sensitive. Submit them in their original case — unlike EVM, lowercased addresses will not match.
Parsing Smart Contract Events (EVM)
Custom-event ABI decoding is an EVM-only feature. Bitcoin and Solana payloads are pre-parsed into their native shapes and do not require ABI decoding.
import Moralis from "moralis";
import { BigNumber } from "@moralisweb3/core";
interface URI {
value: string;
id: BigNumber;
}
const webhookData = {
confirmed: true,
chainId: "0x1",
abi: [
{
anonymous: false,
inputs: [
{ indexed: false, internalType: "string", name: "value", type: "string" },
{ indexed: true, internalType: "uint256", name: "id", type: "uint256" },
],
name: "URI",
type: "event",
},
],
logs: [
{
logIndex: "475",
transactionHash:
"0x55125fa34ce16c295c222d48fc3efe210864dc2fb017f5965b4e3743d72342d5",
address: "0x495f947276749ce646f68ac8c248420045cb7b5e",
data: "0x0000000000000000000000000000000000000000000000000000000000000020...",
topic0:
"0x6bb7ff708619ba0610cba295a58592e0451dee2622938c8755667688daf3529b",
topic1:
"0xab6953e647a36018fc48d6223583597b84c755a0000000000000010000000001",
topic2: null,
topic3: null,
},
],
erc20Transfers: [],
erc20Approvals: [],
nftApprovals: { ERC1155: [], ERC721: [] },
nftTransfers: [],
};
const decodedLogs = Moralis.Streams.parsedLogs<URI>(webhookData);
console.log(decodedLogs[0].value);
console.log(decodedLogs[0].id.toString());
Notes
- On EVM, prefer the dedicated parsed arrays (
erc20Transfers, nftTransfers, etc.) over decoding raw logs yourself.
- On EVM, custom-event decoding relies on the ABI you configure for the stream — raw logs remain available in the payload alongside parsed data.
- On Bitcoin, output addresses and values are already parsed; no decoding step is needed.
- On Solana, account keys, instructions, and SPL balance snapshots are already parsed; subtract pre/post token balances to derive deltas.
