NATS Python API Docs | dltHub
Build a NATS-to-database pipeline in Python using dlt with AI harness support for Claude Code, Cursor, and Codex.
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NATS provides a lightweight HTTP monitoring API that exposes real-time server statistics, connection information, and JetStream metrics. The REST API base URL is http://localhost:8222 and monitoring endpoints do not require authentication.
dlt is an open-source Python library that handles authentication, pagination, and schema evolution automatically. dlthub provides AI context files that enable code assistants to generate production-ready pipelines. Install with uv add "dlt[hub]" and start loading NATS data in under 10 minutes.
What data can I load from NATS?
Here are some of the endpoints you can load from NATS:
| Resource | Endpoint | Method | Data selector | Description |
|---|---|---|---|---|
| server_vars | varz | GET | General server information and statistics | |
| connections | connz | GET | connections | Detailed client connection information with pagination |
| routes | routez | GET | routes | Route information for NATS supercluster |
| gateway_info | gatewayz | GET | gateways | Gateway information for NATS supercluster |
| leaf_nodes | leafz | GET | leafnodes | Information about leaf node connections |
| subscription_routing | subsz | GET | subscriptions | Detailed subscription routing information |
How do I authenticate with the NATS API?
The NATS server monitoring endpoints do not support authentication or authorization, and it is recommended to restrict access via firewall or by binding to localhost.
No credentials required. The NATS API is public, so there is nothing to obtain and nothing to add to .dlt/secrets.toml — the pipeline above runs as written.
How do I set up and run the pipeline?
Set up a virtual environment and install dlt:
uv init uv add "dlt[hub]"
1. Install the dlt AI harness:
uv run dlthub ai init --agent <your-agent> # <agent>: claude | cursor | codex
This installs project rules, a secrets management skill, appropriate ignore files, and configures the dlt MCP server for your agent. Learn more →
2. Install the rest-api-pipeline toolkit:
uv run dlthub ai toolkit install rest-api-pipeline
This loads the skills and context about dlt the agent uses to build the pipeline iteratively, efficiently, and safely. The agent uses MCP tools to inspect credentials — it never needs to read your secrets.toml directly. Learn more →
3. Start LLM-assisted coding:
Use /find-source to load data from the NATS API into DuckDB.
The rest-api-pipeline toolkit takes over from here — it reads relevant API documentation, presents you with options for which endpoints to load, and follows a structured workflow to scaffold, debug, and validate the pipeline step by step.
4. Run the pipeline:
uv run python nats_pipeline.py
If everything is configured correctly, you'll see output like this:
Pipeline nats_pipeline load step completed in 0.26 seconds 1 load package(s) were loaded to destination duckdb and into dataset nats_data The duckdb destination used duckdb:/nats.duckdb location to store data Load package 1749667187.541553 is LOADED and contains no failed jobs
Inspect your pipeline and data:
uv run dlthub show
This opens the Pipeline Dashboard where you can verify pipeline state, load metrics, schema (tables, columns, types), and query the loaded data directly.
Python pipeline example
This example loads /varz and /connz from the NATS API into DuckDB. It mirrors the endpoint and data selector configuration from the table above:
import dlt from dlt.sources.rest_api import RESTAPIConfig, rest_api_resources @dlt.source def nats_source(): config: RESTAPIConfig = { "client": { "base_url": "http://localhost:8222", }, "resources": [ {"name": "connections", "endpoint": {"path": "connz", "data_selector": "connections"}}, {"name": "leaf_nodes", "endpoint": {"path": "leafz", "data_selector": "leafnodes"}} ], } yield from rest_api_resources(config) def get_data() -> None: pipeline = dlt.pipeline( pipeline_name="nats_pipeline", destination="duckdb", dataset_name="nats_data", ) load_info = pipeline.run(nats_source()) print(load_info)
To add more endpoints, append entries from the resource table to the "resources" list using the same name, path, and data_selector pattern.
How do I query the loaded data?
Once the pipeline runs, dlt creates one table per resource. You can query with Python or SQL.
Python (pandas DataFrame):
import dlt data = dlt.pipeline("nats_pipeline").dataset() sessions_df = data.connz.df() print(sessions_df.head())
SQL (DuckDB example):
SELECT * FROM nats_data.connz LIMIT 10;
In a marimo or Jupyter notebook:
import dlt data = dlt.pipeline("nats_pipeline").dataset() data.connz.df().head()
See how to explore your data in marimo Notebooks and how to query your data in Python with dataset.
What destinations can I load NATS data to?
dlt supports loading into any of these destinations — only the destination parameter changes:
| Destination | Example value |
|---|---|
| DuckDB (local, default) | "duckdb" |
| PostgreSQL | "postgres" |
| BigQuery | "bigquery" |
| Snowflake | "snowflake" |
| Redshift | "redshift" |
| Databricks | "databricks" |
| Filesystem (S3, GCS, Azure) | "filesystem" |
Change the destination in dlt.pipeline(destination="snowflake") and add credentials in .dlt/secrets.toml. See the full destinations list.
Next steps
Continue your data engineering journey with the other toolkits of the dltHub AI harness:
data-exploration— Build custom notebooks, charts, and dashboards for deeper analysis with marimo notebooks.dlthub-platform— Deploy, schedule, and monitor your pipeline in production.
uv run dlthub ai toolkit install data-exploration uv run dlthub ai toolkit install dlthub-platform
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