Privacy Policy for STL View
Effective date: August 14, 2026
Last updated: September 15, 2026
Alper Vural ("we," "us," or "our") provides the STL View mobile application (the "App"). This Privacy Policy explains how information is handled when you use the App.
1. Privacy at a Glance
STL View is a local-first 3D model viewer. You do not need to create an account to use the App. STL and geometry-only OBJ files are opened and processed on your device. We do not upload your model files, model contents, filenames, file paths, document addresses, geometry, dimensions, or triangle counts to our servers, advertising providers, or analytics services.
The App reports a small set of anonymous, aggregate usage counters (for example, how often the App is opened and which model formats fail to load) to our analytics provider. These counters carry no account, no advertising identifier, and no identifier that persists between sessions, and they never include your files or anything derived from their contents. You can switch them off in Settings → Privacy. Section 2.4 describes exactly what is sent.
The App may display advertising supplied by Google AdMob. When advertising is enabled, Google and its advertising partners may automatically process certain device, advertising, usage, and diagnostic information as described below. The App uses Google's User Messaging Platform (UMP) to present and manage privacy choices where required.
2. Information Handled by the App
2.1 Model Files and Recent Files
When you choose, open, or share an STL or OBJ file:
- the file is processed locally on your device;
- the App may create a temporary, app-controlled copy so that it can safely open and display the file;
- the App stores an app-controlled local copy of recently opened files, together with the filename, file type, file size, and last-opened date, so that you can reopen them from the Recent Files list; and
- the Recent Files list is limited to 20 entries. When the limit is exceeded, older app-controlled copies are removed.
These files and details remain on your device and are not sent to us. The App does not rename, move, modify, or delete your original source file. Temporary copies are deleted when they are no longer required under the App's normal cleanup process. Recent-file copies remain until you remove an entry, clear the Recent Files list, uninstall the App, or the operating system removes the App's data.
If you use the system share sheet, the file is disclosed only to the app, service, or person you select. Their handling of the file is governed by their own privacy practices.
2.2 App Preferences
The App may store preferences such as your selected display language and your Anonymous usage statistics choice on your device, together with the rough usage tally described in Section 2.4. These preferences are used only to provide and remember App functionality and are not sent to us.
2.3 Advertising and Privacy Information
The free version of the App may use Google AdMob to display banner advertisements. Depending on your device, settings, region, consent choices, and Google's configuration, the Google Mobile Ads SDK and participating advertising partners may automatically collect or receive information such as:
- your IP address and general location inferred from it;
- device and app information, including operating system, App version, language, and device type;
- advertising, app-set, vendor, or similar device identifiers where available and permitted;
- ad impressions, ad interactions, App launches, taps, and related usage information;
- diagnostic and performance information, such as crash data, launch time, hang rate, and energy usage; and
- privacy and consent signals used to determine whether and how ads may be requested.
This information may be used for delivering and measuring ads, limiting repeated ads, analytics, security, fraud prevention, and, where permitted, ad personalization. Non-personalized or limited ads may still use contextual information, IP-derived general location, device information, and limited identifiers for functions such as ad delivery, measurement, and fraud prevention.
STL View does not add your model files or model-related information to ad requests. The advertising information described in this section is separate from the anonymous usage counters described in Section 2.4; the two are not combined, and neither carries your files or anything derived from their contents.
For more information, see:
- How Google uses information from sites or apps that use its services
- Google Privacy Policy
- Google advertising controls
2.4 Anonymous Usage Statistics
The App reports a small set of anonymous, aggregate usage counters to Amplitude, an analytics provider, so that we can see how the App is used and where it fails. This reporting is built so that it cannot identify you or your device:
- No identifier that persists. Each report carries a random identifier generated in memory each time the App starts. It is never written to your device, so every launch produces a new identifier and separate sessions cannot be linked to each other or to you.
- Rough counts kept on your device. So that we can tell whether people come back to the App, it keeps a small local tally: the calendar day it was first and last opened, how many times it has been opened, and how many models it has opened. This tally never leaves your device as it is. Reports only say which broad range it falls in (for example, "second launch", "1-6 days since first use", or "2-5 models opened"), and it contains no identifier.
- No account or device identifier. No user ID, email address, advertising identifier (IDFA or Android advertising ID), vendor identifier, device model, operating-system version, carrier, or device language setting is sent.
- No location. The IP field of every report is set to a loopback address, so no location can be derived from it.
- No file information. No filename, file path, document address, model content, geometry, dimensions, or exact file size or triangle count is sent.
The complete set of information transmitted is:
- the event name, which is one of: App opened, model opened, model failed to open, file could not be received, viewer tool used, unexpected App error, model shared, purchase outcome, interface language selected;
- the broad usage ranges described above: launch-count range, days since first use, days since the previous launch, and models-opened range, and whether this is the App's very first launch;
- coarse ranges instead of exact values, namely a file-size band (for example, "5-25 MB") and a triangle-count band (for example, "100k-500k");
- the model format (STL binary, STL ASCII, OBJ, or 3MF) and where the model was opened from (file picker, recent files, bundled sample, "Open with", or the share sheet);
- when a file could not be received, a fixed reason code (for example, cancelled or unsupported format) and, for a recognized but unsupported design format, its family (for example, STEP);
- for a viewer tool, its fixed name (for example, measure, section, or print estimate), counted at most once per opened model;
- for a failure or an unexpected App error, a fixed error code, the processing stage or App area in which it occurred, and the technical type and system code of the underlying error (never its message, stack trace, or any file path);
- for a purchase, whether it completed, was restored, was cancelled, or failed;
- the interface language code you selected, when you change it;
- the App version and the platform name ("iOS" or "Android"); and
- the time of the event and the per-launch random identifier described above.
Reports are sent to Amplitude and are processed on Amplitude's servers in the United States. Because a report carries no identifier that persists between sessions and no IP address, it is not linked to you, and this processing is described here for transparency rather than because the records identify anyone. Apart from the rough local tally described above, nothing is stored on your device for this purpose: if the App has no network connection, that session's counters are discarded rather than saved for later.
Turning it off. You can switch Anonymous usage statistics off at any time under Settings → Privacy. Turning it off discards anything not yet sent, erases the local tally, and stops all further reporting. Your choice is stored on your device so that it is remembered.
Because this information is not tied to any identifier that persists between sessions, we treat it as anonymous statistical data. Where a legal basis is required, we rely on our legitimate interest in understanding aggregate usage and reliability of the App, together with the opt-out described above.
2.5 Purchases
The App may offer a one-time, non-consumable purchase to remove ads. Purchases are processed by Google Play or Apple's App Store, not directly by us. The store may process information such as your store account, payment information, transaction identifier, purchase status, and purchase history under its own privacy policy.
To verify and restore a purchase, the App and an authorized purchase-verification service may process a product identifier, transaction status, receipt, purchase token, signed transaction data, or similar proof supplied by the store. We use this information only to verify entitlement, prevent fraud, complete the transaction, and restore your purchase. Raw purchase proof is not stored in the App's user interface or written to App logs. The App stores an encrypted local marker indicating that the store previously confirmed the remove-ads entitlement; this marker is not a receipt or payment record.
2.6 Support Communications
If you contact us by email, we receive the information you choose to provide, such as your email address, message, and attachments. Please do not attach confidential model files unless you intentionally want us to review them. We use support communications to respond to you, troubleshoot issues, protect the App, and maintain appropriate business records.
3. How We Use Information
Where applicable, information is used to:
- provide, operate, maintain, and improve the App;
- open, display, remember, and share files at your direction;
- save your local preferences;
- understand, in aggregate and anonymously, how often the App is used, whether people return to it, which model formats and tools are used, and which errors occur, so that we can fix problems and prioritize improvements;
- display, personalize where permitted, and measure advertising;
- obtain and respect applicable privacy choices;
- process, verify, and restore purchases;
- detect fraud, abuse, security incidents, and technical problems;
- respond to support requests; and
- comply with legal obligations and enforce our rights.
Where data-protection law requires a legal basis, we rely as applicable on your consent, performance of a contract with you, compliance with legal obligations, and our legitimate interests in providing, securing, supporting, and sustainably funding the App. You may withdraw consent at any time through the available privacy controls, without affecting processing that occurred before withdrawal.
4. When Information Is Shared
We do not sell your model files or model-related information. We may disclose other information only as follows:
- Advertising providers: Google AdMob and participating advertising partners may receive the advertising information described above.
- Analytics provider: Amplitude receives the anonymous usage counters described in Section 2.4, and nothing else. It receives no account identifier, no advertising identifier, and no identifier that persists between your sessions.
- App stores and purchase-verification providers: Google, Apple, and an authorized verifier may process purchase information to complete, verify, or restore transactions.
- Your chosen recipients: A file is shared when you deliberately select a recipient through your device's share interface.
- Service providers: Providers that help us operate support or other necessary business functions may process information on our behalf and under appropriate obligations.
- Legal and safety reasons: We may disclose information when reasonably necessary to comply with law, legal process, or valid government requests, or to protect rights, safety, property, users, and the public.
- Business transfers: Information may be transferred as part of a merger, acquisition, financing, reorganization, or sale of all or part of our business, subject to applicable law.
5. Retention and Deletion
- Model files, recent-file metadata, and preferences stored by the App remain on your device as described in Section 2. You can remove individual recent files or clear the Recent Files list in the App. Uninstalling the App normally removes App-controlled local data, subject to operating-system backups and platform behavior.
- Anonymous usage counters are retained by our analytics provider under our project's configured retention period. Because they carry no identifier that persists between sessions, they cannot be traced back to you or to a particular device, and individual records therefore cannot be located or deleted on request.
- Advertising and purchase providers retain information according to their own policies and legal obligations.
- We retain support emails only for as long as reasonably needed to respond, keep necessary business records, resolve disputes, enforce agreements, and meet legal requirements.
6. Your Choices and Rights
Depending on your location, you may have rights to access, correct, delete, restrict, object to, or obtain a copy of personal information, withdraw consent, or appeal a privacy-request decision.
You can also:
- use Manage ad privacy choices in the App when that option is required and available;
- switch Anonymous usage statistics off under Settings → Privacy;
- use your device's advertising and privacy settings;
- use Google My Ad Center to manage Google advertising preferences;
- remove files from Recent Files or clear the list; and
- contact us using the address below.
We do not sell personal information for money. Some advertising disclosures may be considered "sharing," "targeted advertising," or a "sale" under certain privacy laws even when no money is exchanged. Where applicable, use the App's ad privacy controls, your device settings, or contact us to exercise an opt-out right. We will not discriminate against you for exercising a privacy right.
Because model files and most App preferences stay only on your device and are not received by us, we generally cannot access, retrieve, or delete that local information for you.
7. International Data Transfers
Google, Apple, advertising partners, our analytics provider, purchase-verification providers, and support-service providers may process information in countries other than your own. In particular, the anonymous usage counters described in Section 2.4 are processed in the United States. Where required, we and our providers use recognized safeguards for international transfers. Please review each provider's privacy policy for details about its locations and transfer mechanisms.
8. Security
We use reasonable technical and organizational measures designed to protect information. Model processing is local, App-controlled file paths are isolated from the advertising boundary, and eligible purchase status is stored using secure device storage. However, no device, storage method, or transmission system is completely secure. You are responsible for controlling access to your device and for deciding which files to open or share.
9. Children's Privacy
The App is not directed to children under 13 or the minimum age required by local law to consent to data processing. We do not knowingly collect personal information directly from children. If you believe a child has provided personal information to us, please contact us so that we can take appropriate action. Advertising availability and treatment may be restricted where required by law or platform policy.
10. Third-Party Services
Third-party services used with the App operate under their own terms and privacy policies. Their practices are not controlled by this Privacy Policy. Relevant services may include Google AdMob, Google Play, Apple's App Store, Amplitude, a purchase-verification provider, your email provider, and any app or service you select when sharing a file.
11. Changes to This Policy
We may update this Privacy Policy to reflect changes to the App, third-party services, or legal requirements. We will update the "Last updated" date and provide any additional notice required by law. Your continued use of the App after an update becomes effective is subject to the updated policy.
12. Contact Us
For privacy questions or requests, contact:
Alper Vural
Email: sakasstudio@gmail.com
If applicable in your jurisdiction, you may also lodge a complaint with your local data-protection authority.
