Last updated: October 2026
Data controller: Tregolam Literatura, S.L. · Tax ID B88024146 · Avda. Ciudad de Barcelona 11, 28007 Madrid · hola@gutterbook.com
Gutter is an automatic editorial layout service developed and operated by Tregolam Literatura, S.L. (hereinafter “Tregolam” or “we”), a company registered in the Madrid Commercial Registry, Volume 37452.
When you sign up for Gutter we collect: your full name, email address, password (encrypted with bcrypt) and billing details (tax name, address, tax ID) for the purchases you make.
We record the uploaded manuscript, the selected book type, the page count, the calculated price, the date of each operation and the generated result (interior PDF and, where applicable, ePub).
Checking our own service. Once your order is finished and delivered, and for as long as we keep your manuscript, our system may read it a second time, in a separate process, solely to compare its result with that of the reading made for your order and so detect errors in our software. This check does not change your book or your order, does not store any copy of your manuscript or any fragment of its text —it only records figures (whether the result matches, how many differences there are and how long it took)— and follows the same deletion periods as the rest of your files. If you would rather we did not do this with your manuscripts, write to hola@gutterbook.com: we will exclude you from this check and delete any that were already recorded, with no consequence for your order or the service. We can also switch it off at any time.
We use technical cookies strictly necessary for the session to work and, only if you accept them, analytics cookies. We do not use advertising cookies. See our Cookie policy.
Origin of the visit. If you accept analytics cookies, we store where you reach Gutter from: the website you came from (for example, tregolam.com or correctores.es), the tag of the link, if it has one, and the first page you visited. When you create an account, that data is linked to it. We use it only to learn which links and pages bring us users, so we can improve how we promote Gutter. We do not use it to build profiles and we do not hand it to third parties.
Legal basis: your consent. You can withdraw it at any time from the cookie settings and, if you do not give it, we store no origin data at all. Retention: the cookie lasts 90 days; the data linked to your account is deleted 25 months after you sign up (even if the account stays open).
Web analytics. If you accept analytics cookies, we measure the use of Gutter with Google Analytics 4, a service of Google Ireland Limited, to know which pages are visited and improve the service. Legal basis: your consent (Art. 6.1.a GDPR and Art. 22.2 LSSI). You can refuse them or withdraw your consent at any time from “Cookie settings”, without affecting the earlier processing. Google may process this data in the United States under the EU-US Data Privacy Framework. Retention: 2 months.
The manuscripts you upload are processed using deterministic rules (margins, numbering, validation of KDP specifications). To understand the structure of the manuscript and interpret your layout instructions, the document may be processed through the Anthropic API under a data processing agreement with non-training clauses (zero retention). Tregolam does not use your documents to train any model.
Gutter operates under a Zero Data Retention (ZDR) agreement with Anthropic for the text fragments that require assisted classification. The texts sent are not stored on Anthropic’s servers once the response has been generated, are not used for training and are not accessible to third parties. Transfers to Anthropic (USA) are covered by the Standard Contractual Clauses approved by the European Commission, under Article 46 GDPR.
| Provider | Function | Country |
|---|---|---|
| Anthropic, PBC | AI-assisted content classification | USA (SCCs + ZDR) |
| OVH SAS | Hosting | France (EU) |
| Redsys | Payment gateway | Spain (EU) |
| Google Ireland Limited | Web analytics (only with your consent) | Ireland (EU) / USA (EU-US Data Privacy Framework) |
We do not share your data with third parties for advertising purposes and we never sell it.
AI-assisted processing involves an occasional transfer to Anthropic, PBC (San Francisco, California, USA), covered by Standard Contractual Clauses (EU Implementing Decision 2021/914) and by the non-training agreement signed with Anthropic.
Under the GDPR you may exercise at any time your rights of access, rectification, erasure, restriction, portability and objection by writing to hola@gutterbook.com. You may also lodge a complaint with the Spanish Data Protection Agency (www.aepd.es).
We apply TLS encryption in transit, password hashing with bcrypt, role-restricted access, encrypted backups and periodic security audits.
Tregolam Literatura, S.L.
Avda. Ciudad de Barcelona 11, 28007 Madrid
Tax ID B88024146
Email: hola@gutterbook.com