As recorded at collection: Sub2API AI model APIs available for free

Sub2API, operated by Shangan9, is a relay API service that connects to programs supporting the OpenAI format. It can be used with chat apps such as Cherry Studio, NextChat, and LobeChat, and coding tools such as Cursor, Claude Code, and Codex CLI, as well as for simple automation scripts and repeated tests. The operator says it is configured to incur almost no maintenance costs and invites anyone to try it.

After signing up, issue your API key on the site. Enter https://api.shangan9.cc.cd/v1 in the server address field (Base URL) of your existing program, then paste the issued key into the key field. Choose the name of the model you want from the site's model list. If the program requires the full address, enter https://api.shangan9.cc.cd/v1/chat/completions.

The instructions say not to run load tests that send many requests all at once from the start or make unlimited repeated requests for a long time. They recommend checking the connection with a lightweight model, then trying advanced models one by one, and starting with small tasks in coding tools before moving on to large projects. If a particular model is unstable, switch to another or wait and try again. If an error occurs, they ask you to provide the model name, time, and error details, and note that the operator may not be able to resolve every issue.