One screenshot,the whole road.
sharegrab turns a screenshot, a recording or a file into a link. Anything that could identify someone either stays on your Mac or never comes into existence.
1. Capture
The macOS app takes screenshots and recordings through the system ScreenCaptureKit. sharegrab hides its own windows for the shot, so you get exactly what you saw. Screenshots are encoded locally to PNG, JPEG, AVIF or WebP, recordings to MP4 or MOV, and GIFs are made from a recording on the spot.
2. Redact before anything leaves
Before upload the image goes through the Redaction Firewall. It is a scan on your computer, with no network involved:
- text recognition is done by Apple Vision, line by line,
- patterns: email addresses, IBAN, card numbers with a Luhn check, PESEL, SSN, JWT tokens, phone numbers, API keys,
- faces and text can additionally be blurred automatically,
- nothing is covered without your consent: you get a sheet with a preview and confirm what disappears,
- video recordings have redaction off by default; you switch it on separately.
A limit worth knowing: the scan works per line of text, so a value split across two lines, or handwritten, can slip through. That is why the confirmation sheet shows the whole image, not only the hits.
3. Receipt
A short record travels with the file: which categories were redacted, how many, when, and the SHA-256 of the file after redaction. The server stores this record next to the file and you can see it in your panel. It is proof that the version that went out is the version after redaction, and nothing more.
4. Send
The file travels over an encrypted connection to sharegrab.mrb.pl and nowhere else. The app does not contact any other server: no analytics, no crash reports, no update checks. Files above 8 MB are first written to disk and streamed, so memory stays flat. If an upload fails, the file lands in Downloads instead of being lost.
5. Link
A link is 14 characters from an alphabet of 58, without zero, capital O, capital I and lowercase l, so it survives being read out loud. That gives 82 bits of randomness; a link cannot be guessed or scanned for. A link can be marked private (only the logged-in owner opens it) or protected with a password.
6. What the viewer sends your recipient
The page with the preview is deliberately poor in anything that could track:
- no cookies for the visitor until a file password is entered,
- no external scripts, web fonts or analytics,
- headers:
Content-Security-Policy: default-src 'none',Referrer-Policy: no-referrer,X-Frame-Options: DENY,Cache-Control: no-store, - HTML, large SVG and archives are downloaded rather than opened in the browser, with
nosniffandsandbox; images, video, PDF, audio and text get a preview, - a DOCX renders inside a sandboxed frame with no access to the rest of the page,
- the file type is recognised from its bytes, not its extension.
7. File password
The password is never in the address. The recipient types it into a form, the server checks it with PBKDF2 (100,000 iterations) and sets a cookie with a signed token that stops working when you change the password. There are 10 attempts per 15 minutes, counted against a hash of the IP address that is discarded after an hour.
8. Gone
Every file has a lifetime: from 10 minutes to never, chosen at upload. After that the link answers 410 Gone, the file waits 24 hours in a grace period (you can restore it from the panel), then it is removed together with its thumbnail and preview. Trash works the same way: 24 hours, then it is over. Removing the account removes all files immediately.
What the server knows, and what it does not
| Event | What remains | For how long |
|---|---|---|
| Someone opens a link | file identifier and time | 90 days |
| Someone tries a password | file identifier, hash of the IP, time | 1 hour |
| You log in | only SHA-256 hashes of the code, the link and the session | attempt 15 minutes, session 30 days |
| You upload a file | name, type, size, dates, settings, receipt, password hash | until expiry plus 24 hours |
Not in sharegrab's database: the IP address of people opening links, their browser, system, the page they came from, geolocation, or any advertising identifiers.
To be honest about the rest: the hosting provider's web server keeps standard connection logs (IP address, browser, address, time) independently of this application. The tool has no access to them and the provider decides how long they are kept. Details in the privacy policy.
What stays on your side
- The app keeps the session token in the macOS keychain and settings in user defaults.
- Permissions it asks for: Screen Recording (required) and Microphone (only if you turn on sound for a recording).
- Text and face recognition run on the device, through Apple's system frameworks.
What we do not do
We do not scan file contents on the server. We do not sell or pass data to anyone. We do not load fonts from Google (removed on 22 July 2026), scripts from CDNs or tracking pixels. We do not run visitor analytics. We cannot open files marked private from a browser without the owner being logged in.
Security in numbers
| Item | Value |
|---|---|
| File limit | 50 MB |
| Account limit | 10 GB, counted atomically, trash included |
| Link length | 14 characters, alphabet of 58, 82 bits |
| Password | PBKDF2-SHA256, 100,000 iterations, salt per file |
| Session | 30 days, HttpOnly cookie, SameSite=Lax |
| Login attempts | valid 15 minutes, limited number of code tries |
| Grace period after expiry | 24 hours |
| Access log | 90 days, no IP |
| Tests | 75 end-to-end scenarios (login 29, files 37, upload 9) plus password and format tests |