Engineering logbook software
The engineering logbook for decisions, calculations and project history.
FactaLog is a desktop logbook for engineers. Record what you did, what you decided and why, with the calculations and evidence beside it, in a searchable, dated record that stays on your own machine.
Free for individuals · No account, no sign-up · Windows 10 and 11
Who it is for
Mechanical, structural, civil, electrical and product design engineers, particularly consultants and small teams who bill by the hour and answer for their work long after the project closes.
A client asks why the bracket is 8 mm and not 6. A colleague picks up a project you started. A claim arrives eighteen months after sign-off. The answer is somewhere in your notebook, your inbox, three spreadsheets and your memory. FactaLog puts it in one dated record you can search.
What FactaLog does
A dated record of the work
Each day is a page. Write entries against a client and project as you go, with notes, sketches, photos and links to the documents behind them, and each one lands in the right place on the timeline.
Time recorded where the work is
Start a timer on the entry you are writing. Trackers keep today’s and this week’s hours in view, and labels split them the way you are measured. Time exports to Harvest, and with Pro it becomes invoices.
Decisions with their reasons
Write down what you chose, what you rejected and why, in the entry where it happened. When the drawing is questioned in a year, the reasoning is there.
Calculations that stay live
Math blocks evaluate as you type, with engineering units. The working sits next to the decision it supports, where anyone reading the decision can check it.
Search everything you have written
Ctrl+K searches every word in every entry across every project. Find the bolt spec you settled on in March in seconds.
Seal entries against later change
Seal an entry and FactaLog can show afterwards whether it has changed since. Sealing happens on your device, with your device key.
All FactaLog features · What engineering logbook software should do
Individual Pro
Your logbook on every machine, and your AI assistant working from it
Encrypted sync
Write at your desk, check it on the laptop in the client's meeting room, add the test result from the site PC. The same logbook on up to five of your own devices, each one complete and working offline, catching up when it reconnects.
End-to-end encrypted: content is encrypted on your device before it leaves, and we do not hold the keys.
A local interface for AI assistants
Connect Claude Desktop, or any MCP client you choose, to your own logbook. Ask what you decided about the gearbox last spring, what is still open on a project, or for this month's hours by label, and it answers from what you actually wrote down.
Read-only until you allow writes. The connection runs on your computer; nothing passes through us.
Your records stay on your machine
FactaLog is local-first. Your logbook is a standard SQLite database on your own computer. The free version needs no account, and your content never reaches us. It leaves your machine only when you export it or connect a service yourself.
- No telemetry, analytics or crash reporting from the app
- Optional sync is end-to-end encrypted; we cannot read it
- Export to Markdown, PDF and CSV whenever you like
Pricing in one line
The logbook is free, with no account, no sign-up and no expiry. Individual Pro adds encrypted sync between your devices, a local interface for AI assistants and invoicing, for USD $10/month or $100/year.
Start your engineering logbook
Free for individuals, with no account and no expiry. Windows 10 and 11.