App Store purchase requests can be tampered to buy a hidden ChatGPT tier

This repository is a step-by-step guide for purchasing a ChatGPT Pro 20x subscription through App Store request tampering on a jailbroken iPhone.

The technique works as follows: route the device through a man-in-the-middle proxy chain (Reqable listening on port 9000, forwarding to Clash on port 7890), bypass SSL certificate pinning using SSL Kill Switch 3 injected — via Choicy — into five Apple system daemons (cloudd, amsaccountsd, identityservicesd, akd, nsurlsessiond), intercept the App Store's buyProduct POST request, and swap three fields in the Plist XML body: offerName, price, and salableAdamId. There is also a prerequisite: Apple ID accounts with no prior ChatGPT subscription history must first purchase a Go or Plus plan before this substitution will work.

The Pro 20x tier ($200/month) is described as having been removed from the app's front-end, which is the stated reason interception is necessary. The included reference table covers every current ChatGPT iOS tier from the $8/month Go plan through Pro 20x, with internal offer name strings, salable item IDs, and subscription group IDs for each. The price field uses units of one-thousandth of a dollar, so 200000 maps to $200.00.

The disclaimer frames this as educational. That framing does not change what the technique does: it manipulates a payment request to purchase a product the vendor has deliberately removed from sale. Intercepting and modifying App Store purchase requests violates Apple's developer agreements and terms of service, and depending on jurisdiction could constitute unauthorized computer access or fraud. OpenAI's terms similarly prohibit circumventing access controls.

For practitioners thinking about API integrity or agent security, the repo is a concrete illustration of why client-side purchase validation is insufficient. The attack surface is the gap between what a client sends and what a server trusts. The fact that this technique reportedly produces a real subscription confirmation suggests either that server-side validation of offer identifiers is weaker than expected, or that the Pro 20x product ID remains active in Apple's backend despite being hidden in the UI — a meaningful data point about trust boundaries in subscription flows, even if the described application is one no legitimate developer should replicate.