Amino (JSON) Encoding

interface AminoMsg {
  readonly type: string;
  readonly value: Record<string, any>;
}

const aminoMsg: AminoMsg = {
  type: "cosmos-sdk/MsgSend",
  value: {
    from_address: "cosmos1sender...",
    to_address: "cosmos1recipient...",
    amount: [{ denom: "uatom", amount: "1000000" }],
  },
};

interface StdSignDoc {
  readonly chain_id: string;
  readonly account_number: string;
  readonly sequence: string;
  readonly fee: StdFee;
  readonly msgs: readonly AminoMsg[];
  readonly memo: string;
  readonly timeout_height?: string;
}

import { AminoTypes, createDefaultAminoConverters } from "@cosmjs/stargate";

const aminoTypes = new AminoTypes(createDefaultAminoConverters());

const aminoMsg = aminoTypes.toAmino(encodeObject);
const encodeObject = aminoTypes.fromAmino(aminoMsg);

{
  "/cosmos.bank.v1beta1.MsgSend": {
    aminoType: "cosmos-sdk/MsgSend",
    toAmino: ({ fromAddress, toAddress, amount }) => ({
      from_address: fromAddress,     // camelCase → snake_case
      to_address: toAddress,
      amount: [...amount],
    }),
    fromAmino: ({ from_address, to_address, amount }) => ({
      fromAddress: from_address,     // snake_case → camelCase
      toAddress: to_address,
      amount: [...amount],
    }),
  },
}