Hi,
We’re the developers of TheTochka (https://thetochka.com/), an iOS/Android app that aggregates independent VPN providers, allows users to manage their VPN subscriptions, communicate with provider support, and now also includes an integrated VPN client.
Our VPN client / network engine is based on sing-box, Libbox, and the Apple integration architecture from sing-box-for-apple.
We want to make sure we are fully compliant with GPL-3.0-or-later, respect the upstream project, and correctly document our use of the code before submitting the new version of our app for Apple App Store review.
Our current public Corresponding Source repository is:
https://github.com/TheTochka/thetochka-vpn-client
It contains the GPL-covered VPN engine sources used in the App Store binary, including:
our fork of the Apple client code based on sing-box-for-apple;
the Packet Tunnel / Network Extension code used by our iOS app;
Libbox integration;
our modifications to the engine layer;
the GPL-3.0-or-later license;
preserved upstream copyright notices;
DIFFERENCES.md;
THIRD-PARTY-NOTICES.md;
build instructions;
version / App Store build to Git tag mapping.
The proprietary part of TheTochka - such as the Flutter application UI, catalog, user accounts, payments, backend and partner integrations — is not included in that repository.
We do not claim that TheTochka is affiliated with, endorsed by, or an official product of SagerNet, and we do not use the sing-box or SagerNet branding in a way that implies such a relationship.
- Fork, attribution and distribution
We publicly describe the engine as an:
“Open-source VPN engine based on sing-box / Libbox, distributed under GPL-3.0-or-later.”
We preserve the upstream license and copyright notices and provide the corresponding source code for the GPL-covered engine.
Could you confirm whether you have any objection to:
TheTochka maintaining this public derivative fork;
distributing the fork under GPL-3.0-or-later;
using it as the VPN engine inside our iOS application;
distributing the resulting application through the Apple App Store;
publicly describing the engine as being based on sing-box / Libbox, while clearly stating that TheTochka is not affiliated with or endorsed by SagerNet?
If you would prefer any specific attribution wording, notice, or repository structure, we would be happy to adjust it.
- GPL-3.0 and Apple App Store distribution terms
We also want to clarify one licensing point that is important for our App Store distribution.
As we understand it, GPL-3.0 guarantees recipients certain rights to use, modify and further convey the covered work, while Apple’s App Store distribution terms / standard EULA can include restrictions such as non-transferability.
We are not suggesting that we can unilaterally add an additional permission to upstream code that we do not own.
Instead, we would like to ask whether you, as the upstream copyright holder / maintainer, would be willing to expressly permit distribution of our derivative fork through the Apple App Store, despite any App Store terms that could otherwise conflict with GPL-3.0 redistribution rights.
If you consider it appropriate, this could either be:
a short public confirmation in this issue; or
a more formal additional permission under GPLv3 §7.
For example, a short confirmation along the following lines would be extremely helpful for our compliance records and for Apple App Review:
“I have no objection to TheTochka distributing its derivative fork of sing-box / sing-box-for-apple through the Apple App Store under GPL-3.0-or-later, provided that the GPL license, source-code availability, copyright notices, attribution and non-affiliation requirements are respected.”
If you believe a different wording or a formal GPLv3 §7 permission would be more appropriate, we would be happy to use wording you recommend.
- App Store compliance documentation
We are preparing documentation for Apple App Review showing that:
the VPN engine is based on open-source GPL-covered software;
the source code of the GPL-covered engine is publicly available;
upstream copyright and license notices are preserved;
our modifications are documented;
the exact source corresponding to the submitted App Store build is tagged in Git;
TheTochka does not claim affiliation with SagerNet.
If possible, we would greatly appreciate a short public response confirming that you have no objection to our fork and its App Store distribution under the above conditions.
We would be happy to update our README, notices, attribution, repository structure, or documentation if there is anything you would prefer us to change.
Thanks again for the excellent work on sing-box and sing-box-for-apple.
Best,
Elshan
TheTochka / GreenCats MMC
Hi,
We’re the developers of TheTochka (https://thetochka.com/), an iOS/Android app that aggregates independent VPN providers, allows users to manage their VPN subscriptions, communicate with provider support, and now also includes an integrated VPN client.
Our VPN client / network engine is based on sing-box, Libbox, and the Apple integration architecture from sing-box-for-apple.
We want to make sure we are fully compliant with GPL-3.0-or-later, respect the upstream project, and correctly document our use of the code before submitting the new version of our app for Apple App Store review.
Our current public Corresponding Source repository is:
https://github.com/TheTochka/thetochka-vpn-client
It contains the GPL-covered VPN engine sources used in the App Store binary, including:
our fork of the Apple client code based on sing-box-for-apple;
the Packet Tunnel / Network Extension code used by our iOS app;
Libbox integration;
our modifications to the engine layer;
the GPL-3.0-or-later license;
preserved upstream copyright notices;
DIFFERENCES.md;
THIRD-PARTY-NOTICES.md;
build instructions;
version / App Store build to Git tag mapping.
The proprietary part of TheTochka - such as the Flutter application UI, catalog, user accounts, payments, backend and partner integrations — is not included in that repository.
We do not claim that TheTochka is affiliated with, endorsed by, or an official product of SagerNet, and we do not use the sing-box or SagerNet branding in a way that implies such a relationship.
We publicly describe the engine as an:
“Open-source VPN engine based on sing-box / Libbox, distributed under GPL-3.0-or-later.”
We preserve the upstream license and copyright notices and provide the corresponding source code for the GPL-covered engine.
Could you confirm whether you have any objection to:
TheTochka maintaining this public derivative fork;
distributing the fork under GPL-3.0-or-later;
using it as the VPN engine inside our iOS application;
distributing the resulting application through the Apple App Store;
publicly describing the engine as being based on sing-box / Libbox, while clearly stating that TheTochka is not affiliated with or endorsed by SagerNet?
If you would prefer any specific attribution wording, notice, or repository structure, we would be happy to adjust it.
We also want to clarify one licensing point that is important for our App Store distribution.
As we understand it, GPL-3.0 guarantees recipients certain rights to use, modify and further convey the covered work, while Apple’s App Store distribution terms / standard EULA can include restrictions such as non-transferability.
We are not suggesting that we can unilaterally add an additional permission to upstream code that we do not own.
Instead, we would like to ask whether you, as the upstream copyright holder / maintainer, would be willing to expressly permit distribution of our derivative fork through the Apple App Store, despite any App Store terms that could otherwise conflict with GPL-3.0 redistribution rights.
If you consider it appropriate, this could either be:
a short public confirmation in this issue; or
a more formal additional permission under GPLv3 §7.
For example, a short confirmation along the following lines would be extremely helpful for our compliance records and for Apple App Review:
“I have no objection to TheTochka distributing its derivative fork of sing-box / sing-box-for-apple through the Apple App Store under GPL-3.0-or-later, provided that the GPL license, source-code availability, copyright notices, attribution and non-affiliation requirements are respected.”
If you believe a different wording or a formal GPLv3 §7 permission would be more appropriate, we would be happy to use wording you recommend.
We are preparing documentation for Apple App Review showing that:
the VPN engine is based on open-source GPL-covered software;
the source code of the GPL-covered engine is publicly available;
upstream copyright and license notices are preserved;
our modifications are documented;
the exact source corresponding to the submitted App Store build is tagged in Git;
TheTochka does not claim affiliation with SagerNet.
If possible, we would greatly appreciate a short public response confirming that you have no objection to our fork and its App Store distribution under the above conditions.
We would be happy to update our README, notices, attribution, repository structure, or documentation if there is anything you would prefer us to change.
Thanks again for the excellent work on sing-box and sing-box-for-apple.
Best,
Elshan
TheTochka / GreenCats MMC