Security & privacy
Your files are often confidential. This page lists what we do technically to protect them – without marketing promises we cannot back up.
Processed in Germany
All conversions and checks run on our own servers in a data center in Germany. Your files are not passed on to external conversion or AI services.
In memory only, discarded immediately
Uploaded files and results are held only in memory or in a RAM-only file system and are never written to a disk. They therefore end up in no backup. You receive the result directly as the response to your request; after that everything is discarded. There are no download links that stay valid later.
Virus scan on every upload
Every file is scanned with ClamAV before it is processed. Suspicious files are rejected. If the scanner is unavailable, nothing is processed.
Isolated processing
Conversions run in separate containers without internet access, not as administrator and with limits on memory and time. Only one small service may reach the internet (for sending e-mail and for payments); it has no access to your files.
Access to the server
The server can only be reached with an SSH key, without a password and without signing in as administrator. The firewall lets through only the web ports and the server access, fail2ban blocks repeated failed attempts, and security updates of the operating system are installed automatically. Only a single proxy is reachable from outside; all other services (database, virus scanner, converters) listen on the internal network only.
Protection of the website
The pages send strict security headers (Content-Security-Policy, HSTS, protection against embedding in other sites) and load nothing from foreign servers. Inputs are checked on the server: the file type is recognised from the content and not from the name, sizes, counts and running times are limited, and SVG images are examined for references and scripts.
Access and permissions
The administration area is open only to named addresses; a second factor with a passkey is built in and becomes mandatory at launch. We store API keys only as a checksum, and you can block them at any time in your account. Requests are limited per connection, and both the sign-in code by e-mail and creating short links as a guest require a small computing task against bots.
Availability and backup
All systems are checked every minute; faults are recorded and the operators are notified. Accounts and orders are backed up encrypted every two hours, also to an external storage server, and kept for up to 30 days. Your files never reach the backup, because they are stored nowhere.
Care in development
Every change runs through automatic tests: function of the tools, checks of inputs, accessibility, the database and the licences of all components. New tools are tested against the running server before release, and e-invoices and PDF/A additionally with the official validators.
Encrypted transfer
All connections to this website are encrypted with TLS (HTTPS).
No tracking without your consent
Without your consent we use no tracking cookies and no external analytics services. Only if you choose “Allow statistics” in the banner do we measure page views with Google Analytics – never in your account, sign-in or admin and never with files, file names or entries. For internal statistics we additionally count only anonymous figures per day and tool (for example the number of uses) – without file names, contents or IP addresses. Fonts and icons are served from our own server.
Account without a password
You sign in with a 6-digit code sent by e-mail (valid for 10 minutes, single use, at most 5 attempts). Codes and sessions are stored only as checksums.
Payments via Stripe
We never see your payment details: the payment happens on Stripe’s page. We only learn that, and how much, was paid.
Open components, official rules
We use proven open-source software and check its licenses on every build. The e-invoice check uses the official KoSIT validator with the official XRechnung rule set. All components are listed on the “Open-source licenses” page.
Data processing agreement
For business use we provide a data processing agreement (see the page “Data processing agreement”). What data we keep and for how long is described in the privacy policy.
What we do not (yet) claim
We currently hold no certification such as ISO 27001 and have had no external penetration test. Both are planned for later stages. Checking an invoice does not replace tax advice.