OpenCitations Python API Docs | dltHub

The OpenCitations REST API provides access to citation data and bibliographic metadata. It includes endpoints for retrieving citation counts and reference lists. The API supports various identifiers for data retrieval. The REST API base URL is https://api.opencitations.net/index/v2 and Optional access token via the "authorization" request header (token string)..

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 pip install "dlt[workspace]" and start loading OpenCitations data in under 10 minutes.

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What data can I load from OpenCitations?

Here are some of the endpoints you can load from OpenCitations:

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How do I authenticate with the OpenCitations API?

Optional OpenCitations Access Token may be provided in the HTTP header named "authorization" (set to the token string). Requests without a token work but using a token is recommended for higher rate limits.

1. Get your credentials

1. Visit https://opencitations.net/accesstoken 2) Follow the instructions to request/generate an OpenCitations Access Token 3) Copy the token and place it in the "authorization" header of API requests or in dlt secrets.toml as shown above.

2. Add them to .dlt/secrets.toml

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[sources.opencitations_source]
api_key = "your_opencitations_access_token_here"

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.

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How do I set up and run the pipeline?

Set up a virtual environment and install dlt:

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uv venv && source .venv/bin/activate
uv pip install "dlt[workspace]"

1. Install the dlt AI Workbench:

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dlt 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:

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dlt ai toolkit rest-api-pipeline install

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 OpenCitations 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:

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python opencitations_pipeline.py

If everything is configured correctly, you'll see output like this:

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Pipeline opencitations_pipeline load step completed in 0.26 seconds
1 load package(s) were loaded to destination duckdb and into dataset opencitations_data
The duckdb destination used duckdb:/opencitations.duckdb location to store data
Load package 1749667187.541553 is LOADED and contains no failed jobs

Inspect your pipeline and data:

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dlt pipeline opencitations_pipeline show

This opens the Pipeline Dashboard where you can verify pipeline state, load metrics, schema (tables, columns, types), and query the loaded data directly.

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Python pipeline example

This example loads citations and references from the OpenCitations API into DuckDB. It mirrors the endpoint and data selector configuration from the table above:

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import dlt
from dlt.sources.rest_api import RESTAPIConfig, rest_api_resources

@dlt.source
def opencitations_source(api_key=dlt.secrets.value):
    config: RESTAPIConfig = {
        "client": {
            "base_url": "https://api.opencitations.net/index/v2",
            "auth": {
                "type": "api_key",
                "api_key": api_key,
            },
        },
        "resources": [
            {"name": "citations", "endpoint": {"path": "citations/{id}"}},
            {"name": "references", "endpoint": {"path": "references/{id}"}}
        ],
    }
    yield from rest_api_resources(config)


def get_data() -> None:
    pipeline = dlt.pipeline(
        pipeline_name="opencitations_pipeline",
        destination="duckdb",
        dataset_name="opencitations_data",
    )
    load_info = pipeline.run(opencitations_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.

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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):

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import dlt

data = dlt.pipeline("opencitations_pipeline").dataset()
sessions_df = data.citations.df()
print(sessions_df.head())

SQL (DuckDB example):

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SELECT * FROM opencitations_data.citations LIMIT 10;

In a marimo or Jupyter notebook:

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import dlt

data = dlt.pipeline("opencitations_pipeline").dataset()
data.citations.df().head()

See how to explore your data in marimo Notebooks and how to query your data in Python with dataset.

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What destinations can I load OpenCitations data to?

dlt supports loading into any of these destinations — only the destination parameter changes:

Change the destination in dlt.pipeline(destination="snowflake") and add credentials in .dlt/secrets.toml. See the full destinations list.

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Next steps

Continue your data engineering journey with the other toolkits of the dltHub AI Workbench:

• data-exploration — Build custom notebooks, charts, and dashboards for deeper analysis with marimo notebooks.
• dlthub-runtime — Deploy, schedule, and monitor your pipeline in production.

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dlt ai toolkit data-exploration install
dlt ai toolkit dlthub-runtime install

• How to deploy a pipeline
• How to explore your data in marimo Notebooks
• How to query your data in Python with dataset
• Join the dlt community on Slack