Privacy & terms
What 304 does with your data: as little as possible.
- No account, no cookies, no analytics, no ads. No third-party script or font: everything is served by this site.
- Most tools run entirely in your browser. The text, files, tokens or passwords you give them never leave your device.
- A few tools need the network to work. They are tagged on their card and at the top of their page, and listed below, with who receives what.
| Tool | Sent to | What is sent |
|---|---|---|
| API Tester | The URL you enter, and corsproxy.io if you enable the CORS proxy | Your request (URL, headers and body) |
| DNS Lookup | Google Public DNS (dns.google) | The domain and record type |
| Domain Availability | IANA (data.iana.org), the registry of the domain extension and Google Public DNS | The domain name |
| Email Security | Google Public DNS (dns.google) | The domain, DKIM selectors to try, and the domains its SPF record includes |
| Is It Up? | This site, whose server then requests the site you enter | The domain or URL |
| Post-Quantum Check | This site, whose server then connects to the site you enter | The domain to check |
| Redirect Checker | This site, whose server then requests the link and each address it redirects to | The link |
| Reverse DNS | Google Public DNS (dns.google) | The IP address |
| robots.txt Tester | This site, whose server then fetches the robots.txt of the site you enter | The domain or URL |
| Site Security | This site, whose server then connects to the site you enter | The URL to check |
| Speed Test | Cloudflare (speed.cloudflare.com) | Random test data, nothing from your device |
| Text to Speech | Your browser's speech service (Google in Chrome, Microsoft in Edge…), only with a voice marked online | The text read aloud |
| URL to Markdown | This site, whose server then fetches the page you enter (pasted HTML stays on your device) | The URL of the page |
| What's My IP | This site, which sends them back to you and keeps nothing | Nothing more than any page load: your IP address and the headers your browser sends |
| WHOIS Lookup | IANA (data.iana.org), then the registry of the domain extension or the internet registry of the address, and the domain's registrar (for a .de, this site asks DENIC and keeps nothing) | The domain, IP address or AS number |
These requests go straight from your browser, so the service also sees your IP address, as any website you visit does, and its own privacy policy applies. Site Security, robots.txt Tester and URL to Markdown are the exceptions: the request is made by our server, the site you check never sees you, and nothing is kept, except keyed hashes of your IP address and of the site's, deleted after 10 minutes, used to limit the number of checks per person and per site.
A few tools keep what you give them in your browser, so you find it again when you come back. None of it is sent to the server.
| What, and where | Size | Forget |
|---|---|---|
|
Theme:
your light or dark choice, until you go back to System Local storage
theme |
||
|
Favorites:
the tools you star, until you unstar them Local storage
favorites |
||
|
Homepage:
what you give the field, a text or a file, until the tool you pick reads it, you clear the field, or an hour passes IndexedDB
304-transfer |
||
|
3D Photo:
the AI model (Depth Anything), so it isn't downloaded again Cache storage
3d-photo |
||
|
3D Photo, Background Remover, Image Redactor, Image Upscaler, Object Remover, Speech to Text, Vocal Remover:
the runtime of the AI models (ONNX Runtime), so it isn't downloaded again Cache storage
onnxruntime |
||
|
Background Remover:
the AI model (ISNet), so it isn't downloaded again Cache storage
background-remover |
||
|
Chart Maker:
the table and the chart's settings, until you clear them Local storage
chart-maker |
||
|
Code Editor:
the files open, its settings and the folder last opened, until you close them IndexedDB
code-editor |
||
|
Code Editor:
the folders and files of its workspace, until you delete them Private file system
|
||
|
Expense Splitter:
the people, the expenses and the currency, until you start over Local storage
expense-splitter |
||
|
Image Redactor, OCR:
the language data downloaded by Tesseract, so it isn't downloaded again IndexedDB
keyval-store |
||
|
Image Redactor:
the face detection model (YuNet), so it isn't downloaded again Cache storage
image-redactor |
||
|
Image Upscaler:
the AI model (Real-ESRGAN), so it isn't downloaded again Cache storage
image-upscaler |
||
|
Mind Map:
the map and its display settings, until you clear it Local storage
mind-map |
||
|
Note:
the text, until you clear it Local storage
note |
||
|
Object Remover:
the AI model (MI-GAN), so it isn't downloaded again Cache storage
object-remover |
||
|
PDF Signer:
the signatures you chose to remember, until you remove them Local storage
pdf-signer |
||
|
Phonetic Alphabet:
the voice you picked for each language, until you pick another Local storage
phonetic-alphabet |
||
|
Pixel Art Editor:
the drawing, its frames and their speed, until you start a new one Local storage
pixel-art |
||
|
Screen Ruler:
the calibration of each screen and the unit, until you clear it Local storage
screen-ruler |
||
|
Sound Level Meter:
the correction of each microphone you calibrate and your settings, until you clear it Local storage
sound-level-meter |
||
|
Speech to Text:
the Whisper models used and Silero VAD, so they aren't downloaded again Cache storage
speech-to-text |
||
|
Time Lock:
the progress of each lock you open, and the result once found so it opens again at once, until you forget them IndexedDB
time-lock |
||
|
Time Zone Converter:
the zones you added and the time converted, until you remove them Local storage
timezone-converter |
||
|
Timer:
your settings, the laps and the timers running, so that a reload doesn't stop them, until you reset them Local storage
timer |
||
|
To-Do List:
the tasks, until you remove them Local storage
todo-list |
||
|
Typing Test:
your settings, your best score for each and your last results, until you clear them Local storage
typing-test |
||
|
Vocal Remover:
the AI model (HT Demucs), so it isn't downloaded again Cache storage
vocal-remover |
||
|
Word Cloud:
the text and the cloud's settings, until you clear them Local storage
word-cloud |
||
|
Word to PDF:
LibreOffice, the converter, so it isn't downloaded again Cache storage
word-to-pdf |
The sizes are read by this page in your browser, and anything it finds that isn't described above gets a row too. Download saves it all in a ZIP file, except the downloaded caches, before you forget it. Clearing this site's data in your browser's settings also removes it all.
Like any web server, ours keeps technical access logs: IP address, date, requested page and browser. Not what you give a tool using our server (a link, a domain), which travels in the request's body. They are only used to keep the service running and secure, and are never shared or used to build a profile. The copy we can access is deleted within about a day, once the host has computed its daily traffic totals, and is not archived. Our host, o2switch, also keeps logs of its own to meet its legal obligations.
The email address and message you send through the contact form are emailed to us and not stored on this site. We only use them to reply, and delete the email once your request is handled.
Under the GDPR you can ask to access, correct or erase data about you, or object to its use. Since 304 has no accounts and keeps nothing tied to you, there is usually nothing to hand over, but you can still ask through the contact form.
If you think your data is mishandled, you can also complain to the CNIL (cnil.fr) or to your country's data protection authority.
- The tools are free and provided as is, without warranty. Double-check a result before relying on it.
- Only test sites, APIs and systems you own or are allowed to test.
- Don't use 304 to harm others or to overload the service.
- Tools may change or disappear at any time.
- Publisher
- Dehoard Lab, dehoardlab.org. Contact through the contact form.
- Host
- o2switch SAS, Chemin des Pardiaux, 63000 Clermont-Ferrand, France. +33 4 44 44 60 40, o2switch.fr
Last updated October 7, 2026