The short answer
HMRC's rules make digital platforms report what they pay the people who sell through them. Gaffr asks for your National Insurance number so it can report. It's encrypted, and clients never see it. It appears in full only in Gaffr's report to HMRC. If Gaffr has paid you, a record is kept for five years.
Why does Gaffr need it?
Under HMRC's digital platform rules, a platform asks each individual seller for their details. GOV.UK lists them: full name, home address, date of birth and a tax identification number. For someone living in the UK, that's their "National Insurance number".
Platforms report those details and what they paid to HMRC each year. They give each seller a copy. The small-seller exemption is for goods only, and "does not apply to: the provision of services" (GOV.UK).
Gaffr Live puts it this way: "HMRC requires platforms to report what crew earn. We never show it to clients".
When does Gaffr Live ask for it?
At sign-up, with your address and date of birth. Gaffr asks for it before you can go live or accept work. Your Unique Taxpayer Reference (UTR) is optional.
What does Gaffr do with it?
- encrypts it before storing it
- puts it in the yearly report to HMRC, which only Gaffr admins can download, and every download is logged
- never shows it back in Gaffr Live, and Gaffr's admin screens show only whether one is on file
- shows it masked in the copy of your data you can ask for
Gaffr doesn't deduct tax or National Insurance from your fee. Tax and Self Assessment explains what Gaffr does and doesn't do about tax.
Who sees it?
Clients never do. Gaffr's privacy policy lists what clients never see, including your tax and bank details. It appears in full only in the HMRC report.
How long is it kept?
While you have an account, it's kept so Gaffr can report. If you delete your account and Gaffr has never paid you, none of it is kept.
If Gaffr has paid you, one encrypted record is kept for HMRC. It holds your name, home address, date of birth and National Insurance number. It also holds your UTR, if you gave one, and what Gaffr paid you each calendar year. Nothing else goes with it.
It's kept for five years from the end of the last calendar year Gaffr paid you in. Then it's deleted. HMRC's rules require it, so deleting your account doesn't remove it. The privacy policy has the detail.