Using SQL Offline and on Air-Gapped Machines
Some networks are segregated on purpose — defence, health, finance, industrial control. The machine that holds the data is not allowed to reach the internet, and most analysis tools assume the opposite. Here is what works, and the one limit worth stating plainly.
The Honest Limit, First
The first visit needs a connection, because the page has to come from somewhere. After that it does not. Load it once on a machine that is allowed out, keep the tab open, and it keeps working on a machine that is not.
For a machine that has never had a connection and never will, the answer is a self-hosted build rather than this site — covered at the end.
Ctrl+S does not give you a working copy. The tool is made of script modules and WebAssembly files that a browser save does not capture, and browsers refuse to run modules from a file opened straight off the disk. A save that appears to work will fail as soon as you add a file.The Disconnected Session
- Open the app and let it load fully.
- Cut the network — Wi-Fi off, cable out, or
sudo ip link set eth0 down. Confirm withping -c 2 1.1.1.1; it should report Network is unreachable. - Work. Add files, query them, export the results.
A 200-line stock file loaded as I, with the machine isolated. total on hand by store:
SELECT store, SUM(on_hand) AS total_on_hand FROM I GROUP BY store
average unit cost by store:
SELECT store, AVG(unit_cost) AS avg_unit_cost FROM I GROUP BY store
And the most expensive lines carried:
SELECT * FROM I ORDER BY unit_cost DESC LIMIT 10
All three answered, and exported to Excel, with no route off the machine.
Load it once, then disconnect and keep going.
Open the app →What Works With No Network
| Works | Needs a connection |
|---|---|
| Every supported format, including Parquet and Avro via WebAssembly | The first page load |
| All SQL, including joins across up to 26 files | Reloading the tab, or opening a new one |
| The plain-English box — it is a parser on the page, not a service | |
| Export to CSV, Excel, JSON and Parquet |
The plain-English box is worth singling out. Every other natural-language SQL tool stops dead when the network does, because writing the query is a remote call. This one carries on, which is the clearest possible evidence that your schema was never being sent anywhere. See the guide.
For a Genuinely Air-Gapped Machine
If the machine has no connection at all, you need a copy of the tool on the inside of the boundary. A supported, self-contained build is available on request, intended to be served from an intranet web server or a local static host inside your environment.
What that changes:
- No dependency on this site. The build keeps working whatever happens to clientvirt.com.
- No outside host at all. Every file, including the code editor, is served from your own network, and the hosting provider's own page-load requests disappear with it.
- A fixed version. You control when it changes, which matters when the environment is under change control.
- Reviewable before deployment. Your security team sees exactly what will run, and it does not change underneath them.
It still needs to be served over HTTP or HTTPS from somewhere — opening the files directly from a disk path will not work, for the module and WebAssembly reasons above. Any static web server on the inside will do.
Reasonable Questions
Does anything get sent when the machine reconnects?
No. Nothing is queued, stored or synced. Reconnecting only means that a page reload would now succeed. You can watch this with the network panel open.
How long can I stay disconnected?
Indefinitely, as long as you do not reload the tab. Files live in tab memory; closing or reloading clears them and you add them again.
Can I put it on a USB stick?
Not as a saved page, for the reasons above. The self-hosted build plus any small static server can be carried on removable media and run from there, subject to your own rules about what may cross the boundary.
Will the browser complain about being offline?
The tab itself will not. Some browsers show an offline indicator in the interface; the page is unaffected.
Does this count as an approved tool?
That is your organisation's decision. What helps the conversation is that there is no data flow to assess: the verification guide covers the network panel and the content security policy, which is usually what a review asks for.