What records do I actually need to keep?

Enough that somebody who has never met you could rebuild your tax return from it. In practice that means three things.

Income

Every payment from every platform, with the date and the amount. Platform statements are the natural source. Keep tips separately if a platform reports them separately, but they are taxable either way.

Costs

Every allowable cost with a date, amount and description, and a receipt or invoice where one exists. Costs you are not claiming are still worth logging, because they affect what the work really pays you.

Mileage

A log with the date, the journey and the business miles. If you are claiming the mileage method, this IS your evidence, and it is the record HMRC is most likely to ask about because it is usually the largest deduction on the return.

You must keep all of it for at least 5 years after the 31 January deadline for the relevant tax year.

JoltMile keeps all three together and exports the lot as CSV, JSON or a Self Assessment summary. Self-employed records (opens in a new tab).