Affirm Python API Docs | dltHub

Affirm's Direct API is a platform that allows developers to integrate Affirm's financial services, primarily focusing on transaction management. The REST API base URL is https://sandbox.affirm.com/api/v1 and All requests require Basic authentication using an API key as the username and a blank password..

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 Affirm data in under 10 minutes.

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What data can I load from Affirm?

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

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How do I authenticate with the Affirm API?

Authentication uses HTTP Basic Authorization. The API key should be used as the username, with a blank password, and the resulting string base64 encoded for the Authorization header.

1. Get your credentials

Please refer to the Affirm developer portal or your Affirm account dashboard to obtain your API key. Specific steps are not detailed in the provided API reference.

2. Add them to .dlt/secrets.toml

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[sources.affirm_transaction_api_source]
api_key = "your_api_key_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 Affirm 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 affirm_transaction_api_pipeline.py

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

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Pipeline affirm_transaction_api_pipeline load step completed in 0.26 seconds
1 load package(s) were loaded to destination duckdb and into dataset affirm_transaction_api_data
The duckdb destination used duckdb:/affirm_transaction_api.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 affirm_transaction_api_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 transactions and transaction from the Affirm 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 affirm_transaction_api_source(api_key=dlt.secrets.value):
    config: RESTAPIConfig = {
        "client": {
            "base_url": "https://sandbox.affirm.com/api/v1",
            "auth": {
                "type": "http_basic",
                "api_key": api_key,
            },
        },
        "resources": [
            {"name": "transactions", "endpoint": {"path": "transactions", "data_selector": "transactions"}},
            {"name": "transaction", "endpoint": {"path": "transactions/{transaction_id}"}}
        ],
    }
    yield from rest_api_resources(config)


def get_data() -> None:
    pipeline = dlt.pipeline(
        pipeline_name="affirm_transaction_api_pipeline",
        destination="duckdb",
        dataset_name="affirm_transaction_api_data",
    )
    load_info = pipeline.run(affirm_transaction_api_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("affirm_transaction_api_pipeline").dataset()
sessions_df = data.transactions.df()
print(sessions_df.head())

SQL (DuckDB example):

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SELECT * FROM affirm_transaction_api_data.transactions LIMIT 10;

In a marimo or Jupyter notebook:

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import dlt

data = dlt.pipeline("affirm_transaction_api_pipeline").dataset()
data.transactions.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 Affirm 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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Troubleshooting

Authentication Errors

If you encounter a 401 Unauthorized error, ensure that your API key is correctly configured and provided as the username in the Basic Authorization header. Remember that the password field should be left blank.

Rate Limiting

Requests may be subject to rate limits. If you receive a 429 Too Many Requests response, you should implement a retry mechanism with exponential backoff to handle these temporary errors gracefully.

Pagination

The list transactions endpoint supports pagination. If you are not receiving all expected data, verify that your requests are correctly handling pagination parameters (e.g., page, limit, or cursor-based pagination if applicable) to retrieve all available records.

Ensure that the API key is valid to avoid 401 Unauthorized errors. Also, verify endpoint paths and parameters to avoid 404 Not Found errors.

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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