> ## Documentation Index
> Fetch the complete documentation index at: https://relevanceai.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# API integration
> Add custom API keys to connect services Relevance doesn't have built-in, or use the Relevance API key to access the platform programmatically.
## What is API integration?
Relevance AI has [built-in integrations](/integrations/introduction) for dozens of popular services — but if you need to call a custom endpoint or connect a service that isn't on the list, you can add your own API keys. And if you want to access Relevance programmatically — via the SDK — you can generate a Relevance API key.
## What are the benefits of API integration?
Add your own API keys to connect any service or endpoint that Relevance doesn't have a built-in integration for.
Use the Relevance API key to interact with the platform through the SDK.
All keys are encrypted and scoped to your project. Access them safely in tools using template variables.
Call any REST endpoint, pass custom headers and parameters, and use the response in your tool steps.
## How to add a custom API key
If the integration you need isn't available as a built-in, you can add a custom API key:
1. Go to the **Integrations & API Keys** page from the left-hand menu
2. Click **Custom API Keys**
3. Give your key a name, paste the value, and save
Once saved, you can access it in any tool step using the template variable:
```
{{secrets.chains_your_api_key}}
```
This lets you call any external endpoint from an API step or code step while keeping your credentials secure.
## Relevance API key
The Relevance API key is different from custom API keys — it authenticates *you* against the Relevance platform itself. Use it when you want to:
* **Use the Python or JavaScript SDK** to trigger agents, run tools, or manage resources programmatically
* **Connect agents to external platforms** by embedding them outside of Relevance
To generate one, go to **Integrations & API Keys** and click **Relevance API Keys**.
API keys are a form of credential — treat them like passwords. Never share them publicly or commit them to source control.
### Region and URL endpoints
## Frequently asked questions (FAQs)
Custom API keys connect Relevance to an external service you want to call. The Relevance API key connects external code to Relevance itself — it's what you use with the SDK.
Reference it with the template variable `{{secrets.chains_your_key_name}}` in any tool step that supports it, such as an API call or Python code step.
Yes. All keys are encrypted and scoped to your project. They're never exposed in logs or agent responses.
Those are covered on the [Integrations](/integrations/introduction) page. This page is for connecting services that don't have a built-in integration, or for accessing Relevance programmatically.
***
## Next steps
See the full list of built-in integrations and how to use them
Create a tool that uses your API keys to call external services