Architect a tip bot

The tip bot is Dogecoin's native art form – the original ones introduced millions of people to their first DOGE. It's also the perfect capstone: deposits, withdrawals, and instant internal transfers in one small system. This lesson is about the architecture; pair it with the tip-bot starter kit when you're ready to build the whole thing.

The key insight: tips are database rows

A naive tip bot sends an on-chain transaction for every !tip. That fails immediately: every tip pays a miner fee, takes a minute to confirm, and bloats your wallet with dust UTXOs. Every serious tip bot instead runs an internal ledger:

• Deposits are on-chain: each user gets a deposit address; confirmed arrivals credit their ledger balance (exactly the payment-detection pattern).
• Tips are off-chain: instant, free database moves between two users' balances.
• Withdrawals are on-chain: sendtoaddress from the bot's wallet, debited from the ledger.

The bot's node wallet holds the pooled funds; the database records who owns what. The invariant you must protect: sum of all ledger balances ≤ wallet balance. Check it on a schedule and alert yourself if it ever drifts.

Ledger rules that prevent 90% of disasters

• Store amounts as integer koinu (1 DOGE = 100,000,000 koinu, same 10^-8 scheme as satoshis). Floating-point money creates phantom fractions of a DOGE.
• Move money in transactions: debit and credit inside one database transaction with a balance check – WHERE balance >= :amount on the debit, roll back if no row updated.
• Rate-limit withdrawals and add a per-day cap. If a bug or a compromise happens, the cap is what makes it a story instead of a disaster.
• Keep the hot wallet thin: sweep anything beyond a working float to a wallet whose keys the bot machine does not have (see the production checklist).

A Discord skeleton to hang it on

Enough structure to see where every piece goes – balances live in the same SQLite style as the invoice lesson, and rpc is our usual wrapper:

import discord
from discord.ext import commands

intents = discord.Intents.default()
intents.message_content = True            # required for prefix commands
bot = commands.Bot(command_prefix="!", intents=intents)

@bot.command()
async def balance(ctx):
    bal = ledger_balance(ctx.author.id)          # SELECT from your ledger
    await ctx.reply(f"your balance: {bal/1e8:g} DOGE")

@bot.command()
async def deposit(ctx):
    addr = deposit_address(ctx.author.id)        # getnewaddress once, then reuse
    await ctx.author.send(f"deposit address: {addr}")   # DM, not public channel

@bot.command()
async def tip(ctx, member: discord.Member, amount: float):
    koinu = int(round(amount * 1e8))
    if ledger_transfer(ctx.author.id, member.id, koinu):  # atomic debit+credit
        await ctx.reply(f"{ctx.author.display_name} tipped "
                        f"{member.display_name} {amount:g} DOGE. wow.")
    else:
        await ctx.reply("insufficient balance.")

@bot.command()
async def withdraw(ctx, address: str, amount: float):
    check = rpc.call("validateaddress", address)
    if not check.get("isvalid"):
        return await ctx.reply("that doesn't look like a valid address.")
    koinu = int(round(amount * 1e8))
    if not withdraw_allowed(ctx.author.id, koinu):        # limits + balance
        return await ctx.reply("over limit or insufficient balance.")
    txid = rpc.call("sendtoaddress", address, amount)
    ledger_debit(ctx.author.id, koinu, txid)
    await ctx.reply(f"sent. txid: {txid}")

bot.run(BOT_TOKEN)   # token from env, never in source

What's deliberately missing – and is exactly the work that makes it real: the deposit watcher loop (lesson 7, pointed at per-user addresses), the atomic ledger_transfer, withdrawal limits, and abuse controls (cooldowns, minimum tip, blocklist). The starter kit includes a Claude Code prompt that scaffolds all of it on testnet.