Advanced topics related to self-hosting
This guide covers advanced topics related to self-hosting.
Data plane vs. control plane
Braintrust's architecture has two main components: the data plane and the control plane. The data plane is the component that handles the actual data, while the control plane is the component that serves the UI along with metadata.
Data storage
Braintrust self-hosting splits data into a data plane and a control plane. We often refer to this as "hybrid" self-hosting. When you deploy Braintrust in hybrid mode, you host the data plane (API) in your own environment, while the control plane (web app and metadata database) is hosted by Braintrust.
To clarify which data is stored in which location, here is a breakdown of the data stored in each place:
| Data | Location |
|---|---|
| Experiment records (input, output, expected, scores, metadata, traces, spans) | Data plane |
| Log records (input, output, expected, scores, metadata, traces, spans) | Data plane |
| Dataset records (input, output, metadata) | Data plane |
| Prompt playground prompts | Data plane |
| Prompt playground completions | Data plane |
| Human review scores | Data plane |
| Experiment and dataset names | Control plane |
| Project names | Control plane |
| Project settings | Control plane |
| Git metadata about experiments | Control plane |
| Organization info (name, settings) | Control plane |
| Login info (name, email, avatar URL) | Control plane |
| Auth credentials | Clerk |
| API keys (hashed) | Control plane |
| LLM provider secrets (encrypted) | Control plane |
Securing sensitive customer data
Braintrust's servers and employees do not require access to your data plane for it to operate successfully. That means that you can protect it behind a firewall/VPN and physically isolate it from access. When you use the Braintrust web application, it communicates directly with the data plane (via CORS), and the data does not flow through any intermediate systems (the control plane, or otherwise) before reaching your browser. The data plane is also configured by default not to send any telemetry back to the control plane. Because of this architecture, our self-hosted customers do not generally list us as a subprocessor.
Like any third-party software, it is important that you establish the appropriate controls to ensure that your deployment is secure, and we're very happy to help you do so. Ultimately, the goal of the control plane and data plane split is to provide you with the highest levels of security and compliance.
Customizing the webapp URL
The SDKs guide users to https://www.braintrust.dev (or the BRAINTRUST_APP_URL variable) to view their experiments. However,
in certain advanced configurations, you may want to reverse proxy traffic to the BRAINTRUST_APP_URL from the SDKs while pointing users
to a different URL.
To do this, you can set the BRAINTRUST_APP_PUBLIC_URL environment variable to the URL of your webapp. By default, this variable is set to
the value of BRAINTRUST_APP_URL, but you can customize it as you wish. This variable is only used to display information, so even its destination
does not need to be accessible from the SDK.
Constraining SDK to the data plane
If you're self-hosting the data plane, it may also be advantageous to constrain the SDKs to only communicate with your data plane. Normally, they communicate with the control plane to:
- Get your data plane's URL
- Register and retrieve metadata (e.g. about experiments)
- Print URLs to the webapp
The data plane can proxy the endpoints that the SDKs use to communicate with the control plane, allowing your SDKs to only communicate with the data plane
directly. Simply set the BRAINTRUST_APP_URL environment variable to the URL of your data plane and BRAINTRUST_APP_PUBLIC_URL to "https://www.braintrust.dev"
(or the URL of your webapp).
Allow-list URLs
In some cases, you may want to restrict the URLs that the SDKs or API server can communicate with. If so, you should include the following URLs:
Configuring rate limits
By default, the Braintrust API server imposes rate limits against any external
domains it reaches out to, such as the BRAINTRUST_APP_URL. The purpose of
rate-limiting is to prevent unintentionally overloading any external domains,
which may block the API server IP in response.
By default, the rate limit is 100 requests per minute per user auth token. The API server exposes the following variables to configure the rate limits:
OUTBOUND_RATE_LIMIT_MAX_REQUESTS: Configure the number of requests per time window. This can be set to 0 to disable rate limiting. In the braintrust CLI, this variable can be set with the--outbound-rate-limit-max-requestsflag, or theOutboundRateLimitMaxRequestsCloudFormation template parameter.OUTBOUND_RATE_LIMIT_WINDOW_MINUTES: Configure the time window in minutes before the rate limit resets. In the braintrust CLI, this variable can be set with the--outbound-rate-limit-window-minutesflag, or theOutboundRateLimitWindowMinutesCloudFormation template parameter.
Data residency (EU and others)
In the Hybrid (API) deployment:
- All customer data lives wherever you choose to host the data plane.
- All prompts are run on the data plane and in your region of choice.
- If you log a customer's data to Braintrust, it will only touch the servers in your data plane.
- You have API-level and even database-level control to purge customer data to comply with regulations like GDPR.
- Braintrust user info (e.g. your employees who sign into the Braintrust web application) is hosted globally by us, in the US. However, if you need this data to be hosted in your region, reach out to us and we can figure something out.
In the Full deployment, everything including the Braintrust web app is hosted in your region. However, you will be responsible for updating your infrastructure each time we release a new feature.