Sub-processors
Last updated: 23 September 2026
Who processes ChapterFlow data
These are every third party that receives customer data in the course of running ChapterFlow, what each one receives, and where it runs. We publish the region where the provider states it, and say so plainly where the provider does not.
| Provider | Purpose | Data it receives | Region |
|---|---|---|---|
| Supabase | Authentication and the application database | Account email, display name, your books and chapters, credit balance | Singapore (AWS ap-southeast-1) |
| Hostinger | The virtual server the application runs on | All request traffic in transit; no customer content stored at rest | Mumbai, India |
| Anthropic | Generating chapters, articles and story biblesDoes not train on data submitted through the API. | Your brief, story bible, and the chapters being written or reviewed | United States |
| TypeSafe | Automated quality and continuity checks on generated textContractually does not train on customer data; a DPA is available. | Sentences, paragraphs and chapters of your manuscript | Not published by the vendor |
| Dodo Payments | International checkout, as merchant of recordSeller of record for non-Indian customers; an independent controller for payment data. | Billing name, email, country, payment details you enter with them | United States / European Union |
| Razorpay | Indian (INR) checkoutAn independent controller for payment data. | Billing name, email, payment details you enter with them | India |
| Purelymail | Transactional email — invoices and service notices | Your email address and the contents of those messages | United States |
What we deliberately do not send anywhere
Grammar and style checking runs on a LanguageTool instance we host ourselves, on the same server as the application. Your manuscript is not posted to a third-party grammar API to be checked. That was a deliberate choice: an unpublished book is the most sensitive thing a writer owns.
We do not sell personal data, and we do not use customer manuscripts to train any model — ours or anyone else's.
Where your writing is stored
Accounts, books and chapters are stored in Singapore. The application server is in Mumbai, India. Text is sent to the United States while a chapter is being written or reviewed, and the results are stored back in Singapore. We do not currently offer EU data residency; if you need it, write to us before you buy rather than after.
Changes
We update this page when a processor is added or removed. For a data processing agreement, or to ask about any provider here, email support@chapterflow.tech. See also our Privacy Policy.