Privacy policy

Last updated: November 2, 2026. Applies to the Interloper app and the Interloper account service, both by Northkeep Software ("we").

The short version

• The app without an account sends us nothing. It downloads two small files when it starts (a version check and the detection lists) and uploads nothing. Reports stay in your Documents folder.
• Free accounts upload nothing either. Cloud history is part of the Watch plan (and its free trial). With Watch, when "Upload each report to my account" is on, each scan report is sent to your account and stored for you alone.
• Reports are deleted when cloud history ends. If a trial or subscription ends, reports already stored are kept for 30 days (so you can upgrade without losing them) and then deleted automatically.
• Error details only when you click. If a check fails and you click "Send error details", the app sends the check name, the error message (with your user name and computer name removed) and the app and Windows versions - nothing about your files, programs or network.
• File fingerprints for known-malware checks (Watch). With Watch, the app sends the SHA-256 fingerprint of suspicious files it found (a fingerprint, not the file - it cannot be turned back into the file) so our service can check it against a public database of known malware. Nothing is sent on the Free plan; the app checks its own built-in list instead.
• Technician plan: the shop name, contact line and logo you enter, and the customer name you give each PC, are stored with your account so they can appear on reports and in your dashboard.
• We do not sell or share your data, and we never use report contents for advertising.
• You can delete everything - a PC, a report, or your whole account - at any time from the dashboard, and it is gone.

What the app collects

A scan reads information about your PC: running programs and their file paths, network connections, scheduled tasks, startup entries, services, user accounts, installed programs, browser extensions, security settings, hardware make and model, and recent event-log entries. This is what the report is made of. It is written to files in your Documents folder on that PC. The app itself has no analytics, no telemetry and no advertising identifiers.

At start, the app requests two files from our download server: latest.json (is there a newer version?) and signatures.json (newer detection lists). Like any web request these reveal your IP address and the app version to the server that hosts the files (GitHub). Nothing about your scan is included. You can turn the automatic check off under Updates.

What the account service stores

If you create an account we store your email address, your name if you give one, a one-way hash of your password (never the password itself), the plan you are on, and - if you subscribe - the identifiers our payment processor gives us for your subscription. We never see or store card numbers; Stripe handles payment.

For each PC you sign in from, we store a name you can change, a non-reversible hash of the Windows machine identifier (so the same PC is recognised next time), the Windows version and the app version. For each report you upload we store the verdict, the findings (including file paths and user names as they appear in the report), what changed since the previous scan, and the HTML copy of the report. Reports are kept per PC up to your plan's limit (the oldest are removed automatically) and are deleted when you remove the PC or your account.

We keep a short audit log of account events (sign-in, device added, report received, alert sent) for security and support. Server logs with IP addresses are retained for up to 30 days.

How we use it

• To show you your reports and PCs on your dashboard.
• To send the emails you asked for: alerts when a scan needs attention or a PC stops reporting, a weekly summary (Watch plan), password resets, and a welcome message. You can turn alert and weekly emails off under Account; we do not send marketing email.
• To run the service and bill your subscription.

We use report contents to answer your support questions when you send them to us, and in aggregate (never identifying you) to improve detection. We do not sell data, rent lists, or share report contents with anyone except the processors below.

Who else touches the data

• Hosting: the account service and its database run on Railway (US data centres).
• Email: alert and reset emails are delivered through Resend.
• Payments: Stripe processes subscriptions; we receive only the subscription status and identifiers.
• Downloads: the app, updates and detection lists are published on GitHub Releases. When you download from northkeepsoftware.com, Cloudflare (which hosts the website) fetches the file from there and checks its checksum before handing it to you; it sees your IP address like any web server does.
• Known-malware lookups: when that check is switched on, file fingerprints (SHA-256 only, no file names, paths or PC details) are looked up at MalwareBazaar, run by abuse.ch. Answers are cached so the same fingerprint is not sent twice.

Each processor only receives what it needs for its job and is bound by its own privacy terms. We will tell you here if this list changes.

Security

Everything travels over HTTPS. Passwords are hashed with bcrypt. The app stores its sign-in token encrypted with Windows' own data protection (DPAPI) for your user account. Updates are verified by SHA-256 checksum and, once releases are code-signed, by publisher signature before they install.

Your choices and rights

• Use the app without an account, or on the Free plan - nothing is uploaded.
• Turn report upload off per PC (Account in the app) and alert emails off (Account in the dashboard).
• Delete a report, a PC or your entire account from the dashboard. Account deletion removes every report and device immediately; backups age out within 30 days.
• Ask us for a copy of the data we hold about you, or to correct it, at the support address below.

If you are in the EU/UK, the legal basis for processing is the contract you have with us (the service you signed up for) and, for alert emails, your consent, which you can withdraw at any time. If you are in California, we do not sell your personal information.

Children

The service is not directed at children under 16 and we do not knowingly collect their data.

Changes

If this policy changes in a way that matters, we will note it here with a new date and, for account holders, by email.

Contact

Northkeep Software, support@northkeepsoftware.com. See also the support page and the website privacy notice.