Crypto Trading Bot Tax and Record Keeping: What Algo Traders Need to Know

Nobody starts algo trading because they love bookkeeping. But the traders who get hurt at tax time are almost never the ones who lost money on strategy. They are the ones who made money and could not prove what they made, because a bot that fires hundreds of trades a month produces a record-keeping problem that a spreadsheet cannot handle after the fact. This article is a practical guide to keeping clean records as an algorithmic trader. It is educational, not tax advice, and the rules vary by country, so treat it as a framework and confirm specifics with a qualified professional.

Why bots make this hard

Manual traders make a handful of trades and can reconstruct them from memory and statements. A bot does not. It might open and close a position fifty times in a day, each with fees, funding, and a fill price that differs from the signal price. Multiply that across a year and reconstructing it afterward from raw exchange exports is painful and error-prone. The fix is simple in principle: log everything as it happens, in a format you can query later.

Log at the moment of execution

The single best habit is to have your bot write a structured record of every fill the instant it happens, alongside whatever the exchange returns. You want the fields a tax calculation needs, not just the fields your strategy needs.

import csv, datetime

FIELDS = ["timestamp", "symbol", "side", "qty", "price",
          "fee", "fee_currency", "funding", "order_id", "realised_pnl"]

def log_fill(path, fill):
    row = {
        "timestamp": datetime.datetime.utcnow().isoformat(),
        "symbol": fill["symbol"],
        "side": fill["side"],
        "qty": fill["size"],
        "price": fill["price"],
        "fee": fill.get("fee", 0),
        "fee_currency": fill.get("feeCurrency", "USDT"),
        "funding": fill.get("funding", 0),
        "order_id": fill["orderID"],
        "realised_pnl": fill.get("realisedPnl", 0),
    }
    write_header = not _exists(path)
    with open(path, "a", newline="") as f:
        w = csv.DictWriter(f, fieldnames=FIELDS)
        if write_header:
            w.writeheader()
        w.writerow(row)

Store it immutably and back it up. A trade log that lives only on the VPS running your bot is one disk failure away from a very bad afternoon. The VPS deployment guide covers backups, and your monitoring setup can double as a check that logging is still running.

Realised versus unrealised

A distinction that trips people up: most tax systems care about realised gains, the profit locked in when you close a position, not the paper value of open positions. Derivatives like perpetuals often have their own treatment, and funding payments may be handled differently again. Because this varies so much by jurisdiction, the goal of your logging is to capture the raw facts, timestamp, prices, fees, funding, realised PnL per close, so that whatever the local rules are, the data to apply them exists.

import pandas as pd

def annual_summary(log_path, year):
    df = pd.read_csv(log_path, parse_dates=["timestamp"])
    df = df[df["timestamp"].dt.year == year]
    return {
        "realised_pnl": df["realised_pnl"].sum(),
        "total_fees": df["fee"].sum(),
        "total_funding": df["funding"].sum(),
        "trade_count": len(df),
    }

Reconcile against the exchange

Your log and the exchange's records should agree. Periodically pull the official trade history from LMEX and reconcile it against your own log to catch anything your bot missed during a disconnect or crash. The exchange record is the authoritative source, so your log is a convenience and a cross-check, not a replacement. If the two disagree, investigate before tax season, not during it.

Frequently Asked Questions

Q: Is this tax advice?

No. This is educational guidance on record keeping. Tax rules for crypto derivatives differ significantly by country and change over time, so confirm your specific obligations with a qualified tax professional.

Q: Do I owe tax on unrealised gains?

In most jurisdictions tax applies to realised gains when a position closes, but this genuinely varies and some regimes treat derivatives differently. That is exactly why you log realised PnL per close and keep the raw data.

Q: How are funding payments treated?

It depends on jurisdiction, and funding can be treated differently from trading gains. Log funding separately so it can be handled correctly whatever your local rule turns out to be.

Q: What if my log and the exchange disagree?

The exchange record is authoritative. Reconcile regularly, and if there is a gap, likely from a disconnect, fix your logging and reconstruct the missing entries from the official history well before you need the numbers.

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