Security

Updated October 19, 2026

These are facts you can check. We list what we do and what we do not have yet.

The numbers

• An open-source engine computes every total. You can read it at github.com/giltotherescue/slashbooks.
• The AI proposes. Code checks the sums. A person approves.
• Code verifies that each bank statement ties out to the books.

Sign-in and access

• 2-step sign-in with an authenticator app, and passkeys. Google sign-in is also available.
• You can see your signed-in devices and sign out any of them.
• Slashbooks checks new passwords against known breaches.
• Sessions end after a fixed time. Staff sessions also end after a short time without use.
• Client data and firm data are separate. An accountant sees only the clients assigned to them.

Data

• All traffic uses HTTPS. HSTS is on, including subdomains.
• Cloudflare encrypts data at rest.
• Backups are encrypted to a key that we keep offline. We keep backups for 35 days and file copies for 30 days.
• Our restore drill passed on October 16, 2026, and the ledger verified.
• The companies that process data for us are listed on the Privacy Policy and in the next section.

Companies that process data for us

We have not verified the security reports of any company on this list.

• Cloudflare: hosting, database and file storage. It receives all customer data. Attestation: not verified by us.
• OpenAI: the AI model for bookkeeping automation. It receives transaction text, evidence extracts and questions. Attestation: not verified by us.
• Google: the AI model for Ask Slashbooks Help. It receives your question and Help article text, and no company data. Google also provides Google sign-in, if you use it. Attestation: not verified by us.
• AgentMail: company books inboxes, inbound email, and our invitations and notices. It receives email and attachments. Attestation: not verified by us.
• BankSync and Plaid: bank connections, for US institutions only. They send us account details, balances and transactions. Attestation: not verified by us.
• Stripe: only if you connect it. We read charges, payouts and fees with read-only access. Attestation: not verified by us.
• PostHog: visit counts on our public pages. It receives the page, the campaign tags and the country, and no IP address, name or email. Attestation: not verified by us.

On our public pages, we count visits with PostHog, Inc., with no cookies and no IP address. We use no advertising provider.

Email

• Slashbooks verifies the sender (DMARC and DKIM) before it attributes a reply to a client.
• Our outbound email is authenticated with SPF, DKIM and DMARC with policy p=reject.

The AI agents

• Agents run in isolation, with no internet access and no credentials.

What Slashbooks does not do

• It does not hold your money and it cannot move money. Bank and Stripe connections are read-only.
• It does not file tax returns and it does not give tax advice. Tax exports are drafts for a qualified tax professional.
• It does not train AI models on your business data.
• It does not sell or share your data, except with the companies listed above.
• An AI agent cannot pay, approve or close a period, change access, or send free-form email.

Model vendors

The bookkeeping agents use an OpenAI model. Ask Slashbooks Help uses a Google Gemini model.

What we do not have yet

No SOC 2 report yet. We are preparing for a SOC 2 audit.

Report a security issue

Write to hi@slashbooks.co. Our security.txt has the same contact.