Legal

Privacy

Last updated 5 October 2026.

Data controller: Northstar Infinity Works Ltd (trading as PromptFiling), company no. 17326480, registered office C/O ELSG Ltd, Regus, Building 2, Marlins Meadow, Watford WD18 8YA. Contact: hello@promptfiling.co.uk.

What we process, and why

• Company data — names, numbers, registered addresses, filing deadlines. This is public record, published by Companies House. We use it to show deadlines, to send letters to companies whose deadlines approach (our legitimate interest as a filing service; see Why did I get a letter?), and to prepare filings you ask for. Every letter carries a one-click, permanent opt-out.
• Your e-mail address — only if you give it to us: for deadline reminders (consent; every e-mail has a one-click unsubscribe) and for your account (contract).
• Your Companies House authentication code — only if you enter it to authorise a filing. Stored encrypted using AES-256-GCM and AWS Key Management Service (KMS); the filing service opens it when needed to submit your accounts. Account and staff screens do not display the saved code. Release checks reject known code patterns that could log it; those checks reduce risk and are not a guarantee that every possible logging path is covered.
• Payments — handled by Stripe. Card numbers never touch our servers; we hold the payment reference and the invoice.
• First-party analytics — page views on the public site go to our own database (path, traffic source, country, coarse device class, and a visitor identifier derived from the request using a secret and the date, so the identifier changes each day). Letter-link scans are recorded server-side the same way, with letter tokens masked before storage; in addition, scanning a letter's code records against that company's letter that it was opened, when, from which country and region, and on what class of device — never who you are or where exactly — and is used to decide whether writing to that company again is worthwhile. Scan records are deleted after 24 months. These are pseudonymous measurements, not a claim of guaranteed anonymity. First-party page-view records are deleted once they are more than 90 days old by our scheduled daily cleanup. The analytics itself sets no cookies and stores no raw IP or user-agent at rest; signed-in customers and our own staff are excluded. Legitimate interest: knowing whether the site works. Separately from analytics, the site keeps three pieces of functional state: your theme choice (in your browser's localStorage), a coarse location hint used only to time the automatic day/night theme (pf-geo cookie), and a signed-in navigation hint (pf_in cookie). None of them identify you.
• Weekly portfolio digest — customers watching two or more companies get a Monday summary e-mail (mutable in one click from the e-mail itself); it replaces the 30-day per-company accounts reminder rather than adding to it.
• Technical and security logs — rate-limit counters use hashed identifiers. Abuse investigations and blocking records can also contain IP addresses, request paths and timestamps. Hosting and edge providers process connection information to operate and protect the service.

Who processes it for us

Vercel (hosting), Supabase (database, private document storage and first-party analytics in London, United Kingdom), Amazon Web Services (KMS encryption key management), Stripe (payments), Resend (e-mail), and Cloudflare (DNS, edge delivery and security). These providers process the information needed for their part of the service. A London database location does not mean every provider processes all information only in the UK; international processing is subject to the provider agreements and applicable safeguards.

How long

Reminder subscriptions: until you unsubscribe — unsubscribing also erases the signup record behind them. Unconfirmed account registrations are removed after seven days. Account data is kept while your account is active, unless you request erasure. Letter scan events are removed after 24 months. First-party page-view records follow the 90-day cleanup described above. Other security and audit records may remain for service protection, analysis and evidence. Filings, invoices, payment references and the related evidence are retained for accounting and legal obligations, normally for at least six years from the end of the relevant company financial year; deleting an account does not automatically remove these records. Letter opt-outs remain so we can honour the request permanently.

Your rights

Access, correction, deletion, objection, portability — write to hello@promptfiling.co.uk and we act on it. Completed account erasure revokes sign-in methods and sessions, stops reminders, removes the signup and company links, and anonymises the account record. Accounting and filing records can retain information needed to meet legal obligations. Copies already on the Companies House public register are controlled by Companies House; service backups expire under their separate retention arrangements. Contact us if you need details of what remains or want to challenge its retention. If we disappoint you, you can complain to the ICO at ico.org.uk.

What we never do

No selling of data, no advertising trackers, no marketing to your customers, no use of your data to train anything. The full security architecture — including the public audit chain you can verify without trusting us — is on the security page.