BILL Python API Docs | dltHub
Build a BILL-to-database pipeline in Python using dlt with AI harness support for Claude Code, Cursor, and Codex.
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BILL is a cloud-based financial operations platform for AP, AR, and spend & expense management automation. The REST API base URL is https://gateway.prod.bill.com/connect and Requests require either a sessionId and devKey (AP & AR) or an apiToken (Spend & Expense)..
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 BILL data in under 10 minutes.
What data can I load from BILL?
Here are some of the endpoints you can load from BILL:
| Resource | Endpoint | Method | Data selector | Description |
|---|---|---|---|---|
| bills | /v3/bills | GET | results | List bill objects with pagination |
| vendors | /v3/vendors | GET | results | List vendor objects with pagination |
| customers | /v3/customers | GET | results | List customer objects with pagination |
| invoices | /v3/invoices | GET | results | List invoice objects with pagination |
| items | /v3/items | GET | results | List item objects with pagination |
How do I authenticate with the BILL API?
Authentication depends on the API product. For AP & AR, sign in via POST /v3/login to obtain a sessionId, then include sessionId and devKey in headers; for Spend & Expense, include an apiToken header.
1. Get your credentials
- Sign in to your BILL account (Production or Sandbox) at bill.com. 2. Navigate to Settings. 3. Locate the Sync & Integrations section. 4. Select Manage Developer Keys. 5. Click Generate developer key (accept the Terms of Service if prompted). 6. Reload the page after about one minute to view your generated Developer Key. Ensure you also note your Organization ID found at the bottom of the page, as it is required for all API authentication requests.
2. Add them to .dlt/secrets.toml
[sources.bill_source] bill_username = "your_username" bill_password = "your_password" bill_organization_id = "008XXXXXXXXXXXXX" bill_developer_key = "your_developer_key"
dlt reads this automatically at runtime — never hardcode tokens in your pipeline script. For production environments, see setting up credentials with dlt for environment variable and vault-based options.
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 BILL 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 bill_pipeline.py
If everything is configured correctly, you'll see output like this:
Pipeline bill_pipeline load step completed in 0.26 seconds 1 load package(s) were loaded to destination duckdb and into dataset bill_data The duckdb destination used duckdb:/bill.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 /v3/login and /v3/logout from the BILL 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 bill_source(api_token=dlt.secrets.value): config: RESTAPIConfig = { "client": { "base_url": "https://gateway.prod.bill.com/connect", "auth": {"type": "api_key", "api_key": api_token, "name": "apiToken"}, }, "resources": [ {"name": "bills", "endpoint": {"path": "v3/bills", "data_selector": "results"}}, {"name": "vendors", "endpoint": {"path": "v3/vendors", "data_selector": "results"}} ], } yield from rest_api_resources(config) def get_data() -> None: pipeline = dlt.pipeline( pipeline_name="bill_pipeline", destination="duckdb", dataset_name="bill_data", ) load_info = pipeline.run(bill_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("bill_pipeline").dataset() sessions_df = data.bills.df() print(sessions_df.head())
SQL (DuckDB example):
SELECT * FROM bill_data.bills LIMIT 10;
In a marimo or Jupyter notebook:
import dlt data = dlt.pipeline("bill_pipeline").dataset() data.bills.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 BILL 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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