Privacy Policy
Last updated: October 14, 2026
This Privacy Policy explains how FlatDiag ("FlatDiag," "we," "us," or "our") handles information in connection with the FlatDiag mobile application (the "App") and the website at flatdiag.com (the "Site"). FlatDiag is operated by FlatDiag LLC, a limited liability company based in Colorado, USA. FlatDiag is built to be private by design: the App keeps your vehicle data on your device, and sends it to us only if you switch on Send logs to FlatDiag (section 3).
The headline: Everything the App does with your car (VINs, fault codes, live data, and coding backups) happens on your iPhone or Mac. There is no account and no analytics SDK. The App contacts Apple and FlatDiag's own key server to confirm it is a genuine copy, to unlock its built in data and, when you code a module, to fetch that module's key. With an OBDLink CX it also asks the adapter's maker, OBD Solutions, for the adapter's newest firmware, and downloads that firmware if you tap Update; neither request carries anything about you or your car. Your vehicle's data leaves your device only when you export or share it, or when you switch on Send logs to FlatDiag, which sends us a diagnostic report each time you disconnect from the car.
1.The short version
- Your car's data is yours. VINs, fault codes, live data, and coding values/backups are stored locally on your iPhone or Mac. We do not receive them unless you send us a log yourself or switch on Send logs to FlatDiag (section 3).
- No account. You don't sign in or give us your name to use the App.
- No analytics, no tracking. The App contains no advertising or analytics SDKs. Besides the local Bluetooth or WiFi link to your OBD2 adapter, it connects only to Apple (for purchases and to confirm the App is a genuine copy), to OBD Solutions for an OBDLink CX's firmware (below), and to our own key server, which unlocks the App's built in reference data, supplies a module's key if you code that module, and receives the App's diagnostic report if you switch on Send logs to FlatDiag. The receipt check and the key requests carry your App Store receipt, so we can confirm the App is a genuine, licensed copy, and when you code a module they also carry that module's model line and the one time challenge value it returns. They never carry your VIN, your fault codes, your live data, or your coding backups.
- Optional diagnostics. You can turn on crash/diagnostic logging to help you troubleshoot. It's off by default, and you can export or delete it anytime. The log leaves your device only if you send it yourself or switch on Send logs to FlatDiag, which sends it to us each time you disconnect from the car.
- We don't sell your personal information.
2.Your vehicle data on your device
When you connect through a Bluetooth (or WiFi) OBD2 adapter, the App communicates directly between your iPhone and your car. VINs, diagnostic trouble codes, live sensor values, control unit (coding) values, and the automatic backups the App creates before a coding change are all stored locally on your device, in the app's private storage (excluded from iCloud backup). We do not receive this information unless you send us a log yourself or switch on Send logs to FlatDiag (section 3), whose report carries the App's exchanges with your car. Deleting the App removes this on device data, except a small licensing record (which vehicles you have used a paid feature with) that the device Keychain keeps so your purchases keep working if you reinstall; it holds no fault codes, live data, or coding values.
Your OBDLink adapter's firmware
When you connect through an OBDLink CX, the App asks OBD Solutions, the company that makes the adapter, for the adapter's public list of firmware releases (at api.obdlink.com), so it can tell you when a newer one exists. If you tap Update, the App downloads that firmware file from the address the list gives, on OBD Solutions' own site, and installs it on the adapter. These are plain web requests made by the App itself: they carry no VIN, no car data, no App Store receipt and no identifier, and we keep nothing about them. Like any website, OBD Solutions' servers see the request itself, including your device's IP address.
3.Optional diagnostics
To help you troubleshoot, the App includes an optional diagnostics feature that can keep technical logs (and, separately, crash/hang reports) about the App's own operation. This feature is:
- Off by default and opt in. It only runs if you turn it on after a clear consent prompt, and turning it off stops collection immediately;
- Kept on your device. These logs stay in the App's private storage. Nothing sends them automatically unless you switch on Send logs to FlatDiag (below);
- VINs redacted. FlatDiag removes the VINs it recognizes before anything is stored, unless you deliberately include your VIN in an export;
- Fully under your control. You can view, export, and permanently delete this data at any time from within the App.
You can also send us a log yourself at any time: the App has an "Email log to FlatDiag" button, and Settings can share a log through the usual iOS or macOS share sheet. You see the contents before either one goes. Settings also has Report a problem, which sends us what you write together with the App's log when you tap Send report (below).
Sending diagnostics to us
If you turn on Send logs to FlatDiag, the App sends its diagnostic report to us automatically each time you disconnect from the car. This is off until you switch it on. Choosing Share diagnostics in the App's diagnostics prompt switches it on together with the log itself. You can switch sending off again at any time in Settings, and turning the log off turns sending off too.
We ask for this because FlatDiag is developed against a single car. Every other model is built from the factory diagnostic data and tested against a simulator, so the first time the App meets your car is on your driveway. Seeing how it actually behaved there is what lets us fix it for your model.
What we receive is the App talking to the car: which control units answered, how long things took, the raw request and response bytes (which carry the fault codes, live values and coding values the car reported), the coding changes the App wrote (each value before and after), and any crash or hang report, together with the model line, your device model, its iOS or macOS version and the App's version. The report travels with your App Store receipt, so the server can confirm a genuine copy. FlatDiag removes the VINs it recognizes before any of it is written down, and security unlock exchanges are left out entirely. We keep these reports for 30 days and then they delete themselves.
Reporting a problem
In Settings, under Troubleshooting, Report a problem lets you tell us what did not work. Nothing is sent until you tap Send report. Then the App sends us what you wrote, the App's activity log (the same log "Email log to FlatDiag" sends, with the App's exchanges with the car) and, if Keep a diagnostics log is on, the newest part of the diagnostic report described above. FlatDiag removes the VINs it recognizes from all of it, including from what you wrote. The report goes to our key server with your App Store receipt, like the diagnostic report, and we keep it for 30 days, then it deletes itself. Please do not put your name, email address or other personal details in the text unless you want us to have them.
4.Information you provide
If you join our waitlist or email us (for example, at nick@flatdiag.com), we receive the email address and any message you send. We use it only to respond and, if you asked for them, to send you FlatDiag updates. You can ask us to delete it anytime.
5.Website & purchases
Website
The Site is hosted on Cloudflare. As with most websites, our hosting provider automatically logs basic technical data (such as IP address, browser type, and pages requested) for security, abuse prevention, and performance. We do not run advertising or analytics trackers on the Site. Fonts are served from our own domain, so loading a page does not call out to any third party.
Purchases
The App is a free download. Its paid features are unlocked by one time in app purchases, and there is no subscription. Apple processes all payments. We never receive your payment card or billing details. Apple may provide us with limited, aggregated sales and download statistics.
6.How we use information
- To operate, maintain, and improve the App and Site;
- To respond to your inquiries and provide support, using only what you choose to send us (such as an email, a diagnostics file you export, a problem report, or the reports Send logs to FlatDiag sends);
- To send you updates you have requested, which you can opt out of at any time;
- To protect against security issues, abuse, or fraud, and to comply with legal obligations.
7.How we share information
We do not sell your personal information. Your vehicle data reaches us only in a log you send us yourself (by email, the share sheet or Report a problem) or in the reports Send logs to FlatDiag sends. For the limited data described above, we share only:
- Service providers. Cloudflare hosts both our website and our key server, so it processes the technical data described above and the receipt check the App makes, and it stores the diagnostic reports Send logs to FlatDiag sends and the problem reports you send for their 30 days. If you contact us or join the waitlist, our email provider (Google Workspace) processes that message on our behalf.
- Apple. In connection with App Store distribution and purchases, as described above.
- Legal & safety. When required by law, or to protect the rights, safety, or property of FlatDiag, our users, or others.
- Business transfers. In connection with a merger, acquisition, or sale of assets, subject to this policy.
8.Affiliate links & third parties
The Site and App may contain links to third party products and websites, including affiliate links to OBD2 adapters (such as the OBDLink CX). If you click an affiliate link and make a purchase, we may earn a commission at no additional cost to you. Those third party sites and merchants have their own privacy policies, and we are not responsible for their practices. See our Disclaimers & Disclosures.
9.Data retention
On device vehicle data and diagnostic logs remain on your device until you delete them or uninstall the App. We receive them only in a log you email us yourself, which we keep like any other email, or in a report sent by Send logs to FlatDiag or by Report a problem, which deletes itself after 30 days. The key server keeps the App Store transaction identifier from a receipt check in a short lived counter, used only to rate limit abuse; it expires by itself in about an hour. Waitlist and contact emails are kept until you ask us to remove them or they are no longer needed for the purpose you contacted us about.
10.Security
Your vehicle data is kept on your device unless you send us a log or switch on Send logs to FlatDiag, so its security depends largely on the security of your iPhone or Mac (passcode, Face ID/Touch ID, OS updates). We take reasonable measures to protect the limited information we do handle (such as contact emails and diagnostic reports). No method of storage or transmission is 100% secure, and we cannot guarantee absolute security.
11.Your privacy rights
Depending on where you live, you may have rights over your personal information, including to access, correct, delete, or port it, and to opt out of certain processing. This includes residents of the EU/UK (GDPR), California (CCPA/CPRA), Colorado (CPA), and other US states with comprehensive privacy laws.
- Most data lives on your device, so you can view, export, and delete it directly in the App, or remove everything by uninstalling.
- For waitlist/contact emails, email nick@flatdiag.com and we will honor applicable requests.
- We will not discriminate against you for exercising your rights. We do not "sell" or "share" personal information for cross context behavioral advertising.
12.Children
FlatDiag is not directed to children and is intended for users 18 and older. We do not knowingly collect personal information from children under 13 (or the equivalent minimum age in your jurisdiction). If you believe a child has provided us information, contact us and we will delete it.
13.International users
FlatDiag is operated from the United States. Your vehicle data stays on your device unless you send us a log or switch on Send logs to FlatDiag; its reports and the problem reports you send are stored on Cloudflare's network. The receipt check the App makes runs on Cloudflare's global network and is normally answered close to you. If you contact us or join the waitlist from outside the US, the limited information you send (such as your email) may be processed in the US, which may have different data protection laws than your country. Where required, we rely on appropriate safeguards for such processing.
Our key server does not answer requests from a small number of countries and regions that we are not permitted to serve. If you are in one of them, the App will tell you it is unavailable in your region and its built in reference data will not unlock.
14.Changes to this policy
We may update this Privacy Policy from time to time. When we do, we will revise the "Last updated" date above and, for material changes (for example, if we change what the App sends off your device), provide a more prominent notice. Your continued use of FlatDiag after changes take effect means you accept the update.
15.Contact us
Questions about this policy or your data? Email nick@flatdiag.com.