Is Check Writer 123 safe?
Check Writer 123 protects your login, bank details and card payments with HTTPS, hashed passwords, owner-only access to bank details, and card handling by Square. It has not had an independent security audit. This page lists what is in place, what our providers handle, and what we do not have, so you do not have to guess.
Last reviewed October 27, 2026.
What is and is not in place
Each line says who is responsible. “Provided by our provider” means a company we use does it and describes it in its own documentation. We have not independently audited those providers.
| Topic | Status | Details |
|---|---|---|
| HTTPS | In place | Every page and request is served over HTTPS through Cloudflare, so data between your browser and the site is encrypted in transit. |
| Password storage | In place | Passwords are never stored as text. Each one is hashed with PBKDF2 (SHA-256, 100,000 iterations) and a random 16-byte salt that is different for every account. You can also sign in with Google, which means we never see a password at all. |
| Email verification | In place | A new account must confirm its email address before it can open the app. |
| Sign-in sessions | In place | The sign-in cookie is HttpOnly (page scripts cannot read it), Secure (sent only over HTTPS) and SameSite Lax. Signing out ends the session straight away. |
| Card payments | Provided by our provider | Card details are typed into a secure form supplied by Square and go from your browser straight to Square. Our servers receive only a one-time token, never the card number, and we store no card numbers. Square describes its Web Payments form as built to meet PCI requirements. |
| Storage and encryption at rest | Provided by our provider | Your data is stored in Cloudflare D1. Cloudflare's documentation says everything stored in D1 is encrypted at rest with AES-256-GCM, using keys that Cloudflare manages. |
| Backups and recovery | Provided by our provider | Cloudflare's documentation says D1 keeps a history that lets a database be restored to any minute in the last 30 days (called Time Travel). We rely on that feature. We have not published an independent test of a full restore. |
| Who can see bank details | In place | Only the account owner can open and edit bank account details. Invited team members can write and print checks but cannot open or change the bank account details. Account lists in the app show only the last four digits of account numbers. |
| Extra encryption of bank numbers inside the database | Not in place | Routing and account numbers are stored in our database so a check can print its MICR line. They are protected by Cloudflare's encryption at rest and by access controls, but we do not add our own separate field-level encryption on top, and we do not claim to. |
| Independent security audit or certification of our own | Not in place | Check Writer 123 has not had a third-party security audit or penetration test, and we do not hold our own SOC 2 or ISO 27001 certificate. We do not use those names as a claim about ourselves. |
| Selling or sharing your data | In place | We do not sell your information and do not share it with advertisers. The service providers that help us run the site are listed in the Privacy Policy. |
| Deleting your data | In place | Owners can close their account in Settings. That permanently deletes the account, bank accounts, saved payees and check history and cancels any subscription. |
The companies behind the scenes
Cloudflare hosts the site and the database. Cloudflare publishes its own security and compliance reports on its compliance resources page. Those certifications belong to Cloudflare, not to Check Writer 123.
Square processes card payments. Square describes the payment form we use as built to meet PCI requirements, and our own servers never see the card number. See Square's documentation.
Resend sends our emails, such as email verification, password resets and receipts. We cannot email your password, because we do not keep it in readable form.
What you can do to stay safe
- Use a strong password you do not use anywhere else, or sign in with Google.
- Only add bank accounts you own or are authorized to use.
- Keep printed and blank checks somewhere secure, and shred spoiled checks.
- Never share your password. We will never ask for it, in chat or by email.
- Read our guide to protecting your account numbers from fraud and scams.
More detail is in the shorter Security page, the Privacy Policy and the Terms of Service.
Security questions
Is Check Writer 123 safe to use?+
It uses HTTPS, hashed passwords, verified email addresses, owner-only access to bank details and Square for card payments, and its data sits on Cloudflare with encryption at rest. It has not had an independent security audit, and we say so openly. Like any service that handles banking details, it is wise to use a strong, unique password and to print checks only on accounts you control.
Does Check Writer 123 store my credit card number?+
No. Card details go from your browser to Square. We receive a one-time token that lets Square charge the card, and we keep no card numbers, expiry dates or security codes.
Where is my data stored, and is it encrypted?+
On Cloudflare's infrastructure, in a Cloudflare D1 database. Cloudflare documents that D1 data is encrypted at rest, and traffic to the site is encrypted in transit with HTTPS.
Does Check Writer 123 have a SOC 2 or ISO 27001 certification?+
Not for itself. Check Writer 123 has no certification of its own and no independent audit yet. Its hosting provider, Cloudflare, publishes its own compliance reports and certifications on its trust pages, and card payments run through Square. Those belong to those companies and not to us.
Are my backups tested?+
The database provider keeps a 30-day history that supports point-in-time restore, and we rely on it. We have not published an independent restore test, so we do not claim one.
Can my team members see my bank account numbers?+
No. Team members you invite can write and print checks, but only the account owner can open or edit bank account details.
Do you sell my information?+
No. We do not sell personal information and we do not share it with advertisers. See the Privacy Policy for the service providers we use to run the site.
How do I report a security problem?+
Email support@checkwriter123.com with what you found and how to reproduce it. We read every report, reply within one to two business days and fix real problems quickly. Please do not include real account numbers or passwords in the email.
Try it with a free test print
Start free with no card, and see how it works before you add any bank details.