What is nortsub?

NoRtSub is a small tool, documented only in Chinese, that automates logging into ChatGPT accounts using the passwordless email verification code flow instead of typing a password, then extracts the resulting session and converts it into what the README calls sub2api format. The README references two related projects by other authors, openai-cpa and GPTSession2CPAandSub2API, suggesting this tool builds on or interoperates with existing tools in that space. According to the setup instructions, you install Python dependencies, copy an example configuration file, and fill in a proxy server address before running the tool. It offers a web interface reachable at localhost on port 5000, where you enter a key to use it, as well as a command line mode that can process a single login interactively or read a list of accounts in bulk from a file. The README describes real time logging in the web interface for batch processing, and mentions an exchange API that works across multiple domains. The stated purpose, converting personal ChatGPT account logins into a session format usable by other API style tooling, is associated with reselling or proxying access to ChatGPT accounts rather than using the OpenAI API through an official, paid API key. Automating account logins in bulk this way, and converting the resulting sessions into a format meant to be consumed like an API, goes against how OpenAI intends its consumer ChatGPT product to be accessed and can violate its terms of service. The README does not explain what a sub2api format is used for beyond the setup steps, does not name a license, and provides no other documentation such as architecture details or a list of supported providers beyond ChatGPT. Beyond the bare functional description of what the tool automates, there is little further explanation available.