Data
An engagement runs on your production data, so the rules around it are strict and written down. This page is the plain-English version; the binding commitments are part of every engagement agreement.
This website
No cookies, no analytics, no trackers. The calculators run entirely in your browser — the numbers you type never leave the page. Nothing is collected unless you deliberately send it.
One exception, stated because "no cookies" should mean something. Coldstill runs a UK site priced in pounds and a US site priced in dollars, and if your browser's own time zone suggests you are on the wrong one, a small notice offers the other. Dismiss it and that choice is saved on your device so it stops appearing — a single word, never sent anywhere, removed when you clear your browser data. The region guess is made locally from your time zone and language: your IP address is never looked up, and nothing about which pages you read is recorded by us. The site runs on Cloudflare, which handles the request and keeps its own short-lived operational logs, as any host does.
If you use the enquiry form
The form sends what you type straight to one mailbox, and nothing else happens to it.
- What is held: your name, work email, company, and the answers you gave about the task. That is everything the form asks for. Your IP address is also counted against a rate limit, so the form cannot be flooded — it is held for at most 48 hours and is never part of the enquiry itself.
- Where it goes: an email to [email protected], and nowhere else. Three suppliers handle it on the way: Cloudflare hosts the site and runs the form's code, Resend delivers the email, and the mailbox is Google Workspace. No form service, no CRM, no analytics, and the enquiry is not written to any database.
- Where it is handled: delivery runs through Ireland, but all three of those suppliers are US companies, so your details may be processed in the United States. Each publishes a data-processing agreement carrying the UK's approved transfer safeguards.
- Why: to write you the free read you asked for, and to reply about it. Sending the form does not add you to a mailing list.
- Retention: it lives in that one mailbox while the enquiry is live and for up to twelve months after the last exchange, and the mailbox is cleared of older enquiries on a diarised review. Ask sooner and it goes sooner — email [email protected] and it is deleted the same working day.
- Please do not paste confidential material into it. The read needs numbers, not documents.
If you can't send us your data
Then don't. Coldstill does the work in all three routes below — none of them hands you a pipeline to operate — and in two of them your documents never leave your side at all.
| Route | What leaves your side | What you provide |
|---|---|---|
| Built on synthetic data | No documents at all. | A description of the work, and a small real set at the end to prove it. |
| Coldstill works inside your environment | Nothing. The data stays where it is. | Scoped, time-limited access to an environment you own and log. |
| You send a redacted sample | The smallest sample that can answer the question, with personal data removed or masked by you first. | Nothing but the sample. |
Built on synthetic data — no real documents at all
Most of what a model needs to learn from a document is its shape: the fields that matter, the forms they take, the ways they are worded, the places they hide, and the edge cases that trip a general model up. That can be written down and generated rather than collected. Coldstill builds a training corpus for your task from a specification of it — your document types, your field definitions, your formats and conventions, the distributions your values actually take, and the awkward cases your team already knows about.
Nothing confidential is needed to write that specification. Blank templates, public filings, the forms on your own website, a redacted example, or an hour with the person who does the work today are all it usually takes.
The model is then proven exactly as it would be on any other engagement: scored on real held-out data before anything switches, so what you get is a number rather than an assurance. That takes a small evaluation set — a few hundred records, not your corpus — or, where nothing can leave at all, measurement inside your own environment against decisions your team has already made.
Coldstill works inside your environment
The whole engagement — training, evaluation and, if you want it, serving — runs on a machine or cloud account you own, under access you grant, scope and revoke. Your data never crosses your own boundary, your own logs record every action taken, and when the engagement ends the access ends with it. You are not operating anything: Coldstill does the work, just on your side of the fence.
The delivered stack helps here in a way worth checking rather than trusting: nothing in it calls home. The model directory is mounted read-only and the process needs no outbound network access to answer a request, so a model deployed in your environment cannot report anything back to us even by accident.
You send a redacted sample
The default for most engagements, and what the audit is designed around. It runs on a sample plus volume figures, not on your whole corpus, and the terms ask you to remove or mask personal data first. Coldstill can supply the masking rules, so the sample keeps the structure that matters for training while the values that identify anyone do not survive the export. If the task genuinely cannot be assessed without personal data, a data-processing agreement is signed before anything moves.
How your data is protected when you do send it
Only the third route puts your data in Coldstill's hands at all, so these commitments are written to be checkable rather than reassuring.
- One person works on your data. Access is held by the named engagement lead on your contract and no one else — no offshore reviewers, no shared logins, and no one added mid-engagement without your agreement. It goes nowhere you have not approved in writing, which includes the compute it is trained on and any third-party model provider used for an agreed interim stage.
- Encrypted in transit and at rest, and never placed in version control.
- Minimised on purpose. The request is always for the smallest sample that can answer the question — redaction is the default starting point, not an upgrade you have to ask for.
- Infrastructure is named and approved in writing before any data moves, including any third-party model provider used for an agreed interim stage. Nothing is introduced mid-engagement without asking.
- Never pooled, never resold, and never used to train anything for Coldstill or for another client. There is no shared model learning across clients, and nothing your data teaches is carried into anyone else's work.
- Deleted on completion, with written confirmation — within the number of days named in your agreement, and sooner on request.
- A UK GDPR data-processing agreement is part of every engagement where personal data is involved, with Coldstill as processor and you as controller.
Engagement data
What you send — sample documents, historical records, or production logs — is used for one purpose: building and evaluating your model.
- Never used to train anything for Coldstill or for anyone else. There is no shared or general model learning from client data; every model is trained for one client and belongs to that client.
- If the documents are processed on behalf of your own clients — a practice keying supplier invoices, an agency handling CVs — the engagement names you as the client: the model is trained for you, belongs to you, and those records fall under every commitment on this page.
- Never sold, and never shared beyond the compute infrastructure you approve in writing.
- Stored encrypted, and never placed in version control.
- Training runs on infrastructure agreed with you in writing before any data moves.
- Deleted within an agreed number of days of the engagement ending, with written confirmation.
Hosted deployments
Hosting on Coldstill's infrastructure is the one place where live traffic passes through us, and where that is the wrong answer for your data, the same service can be run inside your own environment instead — operated by Coldstill, with production requests never leaving your side.
If Coldstill does host your model, your production data is processed solely to serve your requests, to run the agreed quality checks, and to retrain your model when those checks call for it. Operational logs are kept only for the short agreed window those checks need, then deleted. Everything is encrypted in transit and at rest, and a UK GDPR data-processing agreement is part of every hosted contract. If an agreed interim stage runs your documents through a third-party model provider to build the training logs, that provider is named and approved by you in writing before any document flows.
Model ownership
The weights trained on your data belong to you from day one, whether you run them or Coldstill does. Nothing learned from your data ever benefits Coldstill or another client.
If Coldstill has emailed you
Coldstill sends cold emails. If you received one, here is exactly what is held about you and how to stop it.
- What is held: name, role, work email address, company, the public source your details came from, a one-line note of why your role looked relevant, and a record of when contact was made and whether there was a reply. Nothing sensitive is held.
- Where it came from: your company's website, Companies House, LinkedIn, a public post, or a public job listing. Purchased lists are never used.
- Legal basis: legitimate interests in direct marketing, with the assessment recorded before any email is sent. First emails are individually written; all mail is plain text with no tracking pixels.
- Retention: records of people who never reply are deleted after twelve months, in a monthly purge. An opt-out is honoured the same day and stays on a suppression list, so contact does not resume.
- Your rights: object to the processing, ask what is held, or ask for it to be erased, by writing to the address below. You can also complain to the ICO (ico.org.uk).
The data controller is Coldstill Ltd, company number 17376568, registered in England and Wales at 71–75 Shelton Street, Covent Garden, London, WC2H 9JQ.
Get a free read on your task
Starting costs you no data at all — the read needs two numbers, not documents. Anything confidential only changes hands once an engagement is signed and the terms above apply.
The enquiry form takes six questions and a written read comes back within a working day. Email works just as well: [email protected].