OpenAI
Connect your OpenAI account to use GPT models in Missive.
Connect your OpenAI account to use GPT models for the assistant, prompts, and AI rules.
Missive requires an OpenAI API key, not a ChatGPT subscription. These are separate services with separate billing. Get your API key at platform.openai.com.
Setup
Get your OpenAI API key
Create an OpenAI account if you don't have one.
Go to OpenAI Platform and navigate to Settings > API Keys.
Click Create new secret key and copy it somewhere safe. You won't be able to see it again.
(Optional) Find your Organization ID in Settings > General. You'll need this if your OpenAI account belongs to multiple organizations.
Add the integration in Missive
In Missive, go to Settings > Integrations > click Add integration > search for OpenAI and click Add to Missive.
Enter your API key (required).
Under Advanced settings (optional):
Organization ID — only needed if your OpenAI account belongs to multiple organizations
API Base URL — use
https://eu.api.openai.com/v1for EU data residency; leave blank for the default US endpoint
Click Add.
Share with your team (optional)
To let your team use AI features or create AI rules, share the integration:
Go to Settings > Integrations > OpenAI and click Share integration at the top.
Shared integrations mean everyone uses the same OpenAI API key. All usage bills to your OpenAI account.
Restrict available models (optional)
By default, all models are available to your team. To limit which models they can choose in the Assistant:
Go to Settings > Integrations > OpenAI and scroll to Models.
Select the models you want to make available. Choosing All models automatically includes any future models. Deselecting specific models prevents your team from using them.
Available models
Assistant models
GPT-5.2
Complex reasoning, detailed analysis
Moderate
Highest
GPT-5 Mini
Most daily tasks, good balance of speed and quality
Fast
Good
GPT-5 Nano
Quick tasks, lowest cost
Fastest
Basic
For drafting customer-facing email replies, GPT-5.2 gives the best results. GPT-5 Mini is great for quick tasks like grammar fixes or summaries.
Rule models
GPT-5 Mini
Fast, cost-effective for most tasks (recommended)
GPT-5 (with web search)
Includes real-time web search capability
Data privacy
OpenAI does not use API data to train models unless you explicitly opt in. Prompts and responses are retained for up to 30 days for abuse monitoring, then deleted.
To confirm data sharing is off, go to platform.openai.com > Settings > Data controls > Sharing and verify all three options are Disabled:
Enable sharing of model feedback from the Platform
Share evaluation and fine-tuning data with OpenAI
Share inputs and outputs with OpenAI
OpenAI also offers data residency options for organizations that need data to stay in a specific region. To use EU data residency with Missive, set the API Base URL to https://eu.api.openai.com/v1 in Advanced settings. See our AI FAQ and OpenAI's data controls documentation for details.
Cost and usage
OpenAI bills based on tokens processed (input and output). A token is roughly 3/4 of a word. Check OpenAI's pricing page for current rates.
To put it in perspective: reading a 10-email thread and drafting a reply typically uses 2,000 to 4,000 tokens. At that rate, even heavy daily use of the assistant stays well under a dollar per day with GPT-5 Mini.
Set a monthly budget limit in OpenAI to prevent unexpected charges.
Managing costs
Use the best model for manual tasks. When you trigger AI yourself (drafting a reply, asking the assistant a question), the cost per interaction is negligible. Use GPT-5.2 for the best results.
Use cheaper models for AI rules. Rules run automatically on every matching message, so costs add up. GPT-5 Mini is a better choice for classification and routing.
Add conditions to AI rules. Limit when rules run (e.g., only unassigned conversations, only specific labels) to avoid processing every email.
Monitor usage. Check your OpenAI dashboard regularly.
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