Privacy Policy

Last updated: July 2026

1. What we collect

When you use Writeoff, you upload bank statements, receipts, and invoices (PDFs, CSVs, or images). We process these to extract transaction data — dates, vendor names, and amounts. Your email address and password are used for account authentication only.

During onboarding, we ask for your business type, industry, and tax years. This context helps the AI categorize your transactions more accurately.

2. How we use your data

Your documents are processed to:

Extract transactions (date, vendor, amount) from uploaded statements
Match receipts to transactions
Categorize spending as business or personal using AI
Generate export-ready Schedule C summaries

That is all we do with your data. We do not analyze your spending for marketing, we do not build a profile of you, and we do not sell or share your data with anyone.

3. AI processing — what the AI sees and doesn't see

We use DeepSeek (via OpenRouter) to categorize your transactions. Here's exactly what happens:

The AI sees: transaction date, vendor name (sanitized), and amount. It also sees your industry and business type for context.
The AI does NOT see: your account numbers (masked before processing), your phone numbers (stripped), your email, your address, your full statement PDFs, or any other personal information.
Receipt images: if you upload receipt photos, they are processed by AI vision OCR to extract the vendor, date, and amount. The AI sees the image temporarily to read it — it does not store it.
The AI never writes tax advice. It only categorizes. All explanations come from a fixed, human-written response library.

4. We never train AI models on your data

Your documents and financial data are never used to train any AI model. Period. DeepSeek's API terms explicitly state that API inputs and outputs are not used for model training. This is a core promise of our product.

5. Data minimization

Before any transaction data is sent to the AI for categorization, we sanitize it:

Account numbers are masked (e.g., "xxxx xxxx xxxx 8181" becomes "**** 8181")
Phone numbers are stripped from vendor descriptions
SSN patterns are redacted
Email addresses in vendor strings are redacted
Long reference numbers (15+ digits) are removed

We only send what the AI needs to categorize a transaction: the merchant name, the date, and the amount.

6. Encryption and security

In transit: All traffic uses TLS (HTTPS)
At rest: Data is encrypted at rest in Supabase (PostgreSQL) and Vercel
Authentication: Encrypted session cookies via Supabase Auth
Row-level security: Every database table has RLS enabled — you can only read and write your own data. No user can access another user's data, even if they know the IDs.
File storage: Uploaded files are stored in a private Supabase Storage bucket — only you can access your own files
Security headers: Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, and Referrer-Policy are enforced

7. Data retention

Your data is kept for as long as your account is active. You can delete individual uploads or all of your data at any time from Settings. Deletion is permanent and cannot be undone — when you delete data, it is removed from the database and storage immediately.

If you want your account and all associated data permanently deleted, email hello@writeoff.app.

8. Third-party services

We use the following services to operate Writeoff:

Supabase — authentication and database hosting (encrypted at rest, RLS enabled)
Vercel — web hosting and serverless functions (encrypted at rest)
OpenRouter / DeepSeek — AI categorization (data is processed in real-time, not stored, not used for training)

Each service has its own privacy policy. We do not use any analytics, advertising, or tracking services. We do not sell or share your data with any third party for any purpose.

9. Your rights

Access: You can see all your data in the app at any time
Delete: You can delete individual files or everything from Settings
Export: You can export your transaction data as CSV at any time
Account deletion: Email hello@writeoff.app to permanently delete your account

10. Changes to this policy

If we change how we handle your data, we'll update this page and notify you in the app. We will never weaken these protections retroactively.

11. Contact

Questions about privacy? Email hello@writeoff.app