Cursor

Use 678API in Cursor

Add 678API as an OpenAI-compatible provider with a custom Base URL, API key, and model ID.

ProviderOpenAI Compatible

Base URLhttps://www.678api.com/v1

API KeyKey created in the console

ModelExact model ID from the console

Open model settings

Open Cursor Settings and find Models, API Keys, or the custom provider section.

Add a compatible provider

Select OpenAI Compatible, or use an OpenAI entry that allows a custom Base URL.

Set URL and key

Use https://www.678api.com/v1 and paste your 678API API key.

Add a model

Copy the complete model ID from the console, including its case and version suffix.

Enable and test

Save the model and send a short message from Chat or Agent.

Accounts, built-in models, and switching

Do not sign out of Cursor: your Cursor account powers editor and sync features; the 678API key only authenticates supported model requests.
Not every feature uses 678API: specialized features such as Tab Completion can continue using Cursor's built-in models.
Switching back: disable Override OpenAI Base URL before using built-in models if the global override affects them.
Plan limits: BYOK availability in Chat, Agent, and Edit can depend on your current Cursor plan.

Symptom	Fix
No Verify button	Some versions apply settings automatically. Send a short message and confirm the request in 678API usage logs.
Model not found	Copy the exact model ID again and verify account group access.
Built-in models fail too	Disable `Override OpenAI Base URL` and retry.
Network or TLS error	Confirm `https://www.678api.com/v1`, then test HTTP/1.1 in Cursor's HTTP Compatibility Mode.
Tab does not use 678API	This can be expected: custom keys apply to supported chat models, while Tab Completion may use a built-in model.

Tip

Create a dedicated Cursor key so usage and key rotation remain easy to manage.