> ## Documentation Index
> Fetch the complete documentation index at: https://docs.honeyhive.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Environment Variables
> Configuration reference for HoneyHive Python SDK environment variables
The Python SDK reads the following environment variables. All are optional when the equivalent parameter is passed directly to `HoneyHiveTracer.init()` or the `HoneyHive` client.
## Authentication & Endpoints
| Variable | Description | Default |
| --------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------- |
| `HH_API_KEY` | API key for authenticating with HoneyHive. Also accepts `HONEYHIVE_API_KEY`. | None (required) |
| `HH_PROJECT` | **Deprecated.** Project name. The backend now infers the project from the API key. Still accepted for backwards compatibility. Also accepts `HONEYHIVE_PROJECT`. | None |
| `HH_API_URL` | Base URL for the Data Plane API. Also accepts `HONEYHIVE_SERVER_URL` or `HH_SERVER_URL`. | `https://api.dp1.us.honeyhive.ai` |
| `HH_CP_API_URL` | Base URL for the Control Plane API. Falls back to `HH_API_URL` if not set. The client accepts this URL, but not every SDK surface routes through it yet. Only relevant for [self-hosted federated deployments](/v2/setup/self-hosted#sdk-configuration). | Same as `HH_API_URL` |
## Tracer Behavior
| Variable | Description | Default |
| ------------------------- | ----------------------------------------------------------------------------------------------------------------------- | --------- |
| `HH_SOURCE` | Environment label for traces (e.g., `"prod"`, `"dev"`, `"staging"`). | `"dev"` |
| `HH_SESSION_NAME` | Default session name. | `""` |
| `HH_DISABLE_BATCH` | Disable batched span export. Set to `true` for [serverless environments](/v2/tracing/tracer-initialization#serverless). | `false` |
| `HH_DISABLE_HTTP_TRACING` | Disable automatic HTTP request tracing. Also accepts `HONEYHIVE_DISABLE_HTTP_TRACING`. | `false` |
| `HH_TEST_MODE` | Disable OTLP export and use local-only session IDs. Useful for local development and tests. | `false` |
| `HH_VERBOSE` | Set to `"true"` to enable verbose debug logging. | `"false"` |
| `HH_OTLP_ENABLED` | Enable or disable OTLP span export. | `true` |
## Export & Performance
| Variable | Description | Default |
| --------------------------- | -------------------------------------------------------------------------------------------------------------------- | ------------- |
| `HH_OTLP_PROTOCOL` | OTLP transport protocol (`"http/json"`, `"http/protobuf"`, or `"grpc"`). Also accepts `OTEL_EXPORTER_OTLP_PROTOCOL`. | `"http/json"` |
| `HH_BATCH_SIZE` | Maximum number of spans per export batch. | `100` |
| `HH_FLUSH_INTERVAL` | Interval in seconds between batch exports. | `5.0` |
| `HH_EXPORT_TIMEOUT` | Timeout in seconds for OTLP span exports. | `30` |
| `HH_EXPORT_TIMEOUT_SECONDS` | Timeout in seconds for large data exports via the REST API (e.g., `export()`, `get_by_session_id()`). | `120` |
| `HH_HIGH_CONCURRENCY` | Set to `"true"` to optimize for high-concurrency workloads. | `false` |
## Resource Attributes
| Variable | Description | Default |
| -------------------- | ---------------------------------------------------------------- | ------------- |
| `HH_SERVICE_NAME` | Override the OpenTelemetry `service.name` resource attribute. | Auto-detected |
| `HH_SERVICE_VERSION` | Override the OpenTelemetry `service.version` resource attribute. | Auto-detected |
## Span Limits
| Variable | Description | Default |
| ------------------- | ------------------------------------------------------------------------------------------------------------ | ------- |
| `HH_MAX_ATTRIBUTES` | Maximum number of attributes per span. Core HoneyHive attributes are preserved even when limits are reached. | `128` |
| `HH_MAX_EVENTS` | Maximum number of events per span. | `128` |
| `HH_MAX_LINKS` | Maximum number of links per span. | `128` |
**When to adjust span limits** - The defaults work for most workloads. Consider raising them if your spans carry many attributes (e.g., deep RAG pipelines with dozens of retrieval chunks, or tool-calling agents with large parameter sets). When a limit is reached, new attributes beyond the limit are dropped. Core HoneyHive attributes like `session_id` and `event_type` are always preserved regardless of the limit.
## Experiments
| Variable | Description | Default |
| ----------------------- | ----------------------------- | ------- |
| `HH_EXPERIMENT_ID` | Override the experiment ID. | - |
| `HH_EXPERIMENT_NAME` | Override the experiment name. | - |
| `HH_EXPERIMENT_VARIANT` | Tag the experiment variant. | - |
| `HH_EXPERIMENT_GROUP` | Tag the experiment group. | - |
## Proxy
| Variable | Description | Default |
| ---------------- | ------------------------------------------------------------------------------------- | ------- |
| `HH_HTTP_PROXY` | HTTP proxy URL for SDK requests. Falls back to standard `HTTP_PROXY`. | - |
| `HH_HTTPS_PROXY` | HTTPS proxy URL for SDK requests. Falls back to standard `HTTPS_PROXY`. | - |
| `HH_NO_PROXY` | Comma-separated list of hosts to bypass the proxy. Falls back to standard `NO_PROXY`. | - |
## Telemetry
| Variable | Description | Default |
| -------------- | -------------------------------------------------------------------- | ------- |
| `HH_TELEMETRY` | Enable or disable SDK telemetry. Also accepts `HONEYHIVE_TELEMETRY`. | `true` |
All `HH_*` variables also accept a `HONEYHIVE_*` prefix (e.g., `HONEYHIVE_API_KEY` instead of `HH_API_KEY`). The SDK resolves both prefixes automatically. Where an additional alias exists (e.g., `HONEYHIVE_SERVER_URL`), it is noted in the table above.