OpenAI API Key on iPhone — Free BYOK Chat App

OpenAI in Ensor at a glance

API	OpenAI Responses API (https://api.openai.com/v1)
Web search	OpenAI web search tool
Image input	Yes
PDF input	Yes
Streaming	Yes
Models	Ensor loads the models available to your OpenAI account once your key is added. You can also type any model ID.

How to set up OpenAI on iPhone

Create an API key in OpenAI Platform.
Open Ensor, go to Contacts and tap an AI’s avatar, or create a new AI.
Set Provider to OpenAI and paste your key into API Key.
Choose a model. Ensor loads the models available to your OpenAI account once your key is added. You can also type any model ID.
Tap Test Connection, save, and start chatting.

Good to know

OpenAI API usage is billed by OpenAI to your API account. It is separate from a ChatGPT subscription.
Turn web search on or off per contact. OpenAI may charge separately for search calls.
Requests go directly from your iPhone to OpenAI. There is no Ensor server in between.

Use OpenAI alongside other models

Every AI contact in Ensor has its own provider and key, so you can keep OpenAI next to other models and even put them in the same group chat. Other providers:

Frequently asked questions

Can I use my OpenAI API key on iPhone instead of ChatGPT Plus?

Yes. Ensor is a free iPhone app that uses your own OpenAI API key, so you pay OpenAI per API usage instead of a monthly ChatGPT plan. Note that an API key does not include ChatGPT app features such as voice mode or cloud chat history.

Does Ensor send my OpenAI key to its own server?

No. Your key is stored in the iPhone Keychain and is sent only to OpenAI, in the authorization header of the requests you make.

Is Ensor free to use with OpenAI?

Yes. Ensor is free. Your OpenAI account bills you for the API usage on your key.

Where is my OpenAI API key stored?

In the iPhone Keychain, set to this device only. It is never stored in the app database, never exported and never sent anywhere except the provider’s API.

Use your OpenAI API key on iPhone