Fastfield Python API Docs | dltHub

Build a Fastfield-to-database pipeline in Python using dlt with AI Workbench support for Claude Code, Cursor, and Codex.

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FastField is a mobile forms platform that lets users create, submit, and retrieve form data via RESTful APIs. The REST API base URL is https://api.fastfieldforms.com/v1 and All requests require a Bearer token for 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 pip install "dlt[workspace]" and start loading Fastfield data in under 10 minutes.


What data can I load from Fastfield?

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

## FastField API Endpoints
Resource
---
forms
form_detail
submissions
submission_detail
submit_form

How do I authenticate with the Fastfield API?

FastField uses Bearer token authentication. Include the user token in the Authorization header: Authorization: Bearer <token>.

1. Get your credentials

  1. Log in to the FastField portal (https://app.fastfieldforms.com).\n2. Navigate to the "API" or "Integrations" section.\n3. Look for "User Token" or "API Key" details.\n4. If the token is not displayed, submit a help ticket requesting the API token.\n5. The support team will provide the token which can be used as a Bearer token in API calls.

2. Add them to .dlt/secrets.toml

[sources.fastfield_source] token = "your_fastfield_user_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.


How do I set up and run the pipeline?

Set up a virtual environment and install dlt:

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

1. Install the dlt AI Workbench:

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:

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 Fastfield 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:

python fastfield_pipeline.py

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

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

Inspect your pipeline and data:

dlt pipeline fastfield_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.


Python pipeline example

This example loads forms and submissions from the Fastfield 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 fastfield_source(token=dlt.secrets.value): config: RESTAPIConfig = { "client": { "base_url": "https://api.fastfieldforms.com/v1", "auth": { "type": "bearer", "token": token, }, }, "resources": [ {"name": "forms", "endpoint": {"path": "forms", "data_selector": "forms"}}, {"name": "submissions", "endpoint": {"path": "submissions", "data_selector": "submissions"}} ], } yield from rest_api_resources(config) def get_data() -> None: pipeline = dlt.pipeline( pipeline_name="fastfield_pipeline", destination="duckdb", dataset_name="fastfield_data", ) load_info = pipeline.run(fastfield_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("fastfield_pipeline").dataset() sessions_df = data.submissions.df() print(sessions_df.head())

SQL (DuckDB example):

SELECT * FROM fastfield_data.submissions LIMIT 10;

In a marimo or Jupyter notebook:

import dlt data = dlt.pipeline("fastfield_pipeline").dataset() data.submissions.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 Fastfield data to?

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

DestinationExample 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.


Troubleshooting

Authentication Errors

  • 401 Unauthorized – Occurs when the Bearer token is missing, malformed, or expired. Verify that the Authorization: Bearer <token> header is present and the token is still valid.

Rate Limiting

  • 429 Too Many Requests – FastField may throttle excessive calls. Implement exponential back‑off and respect any Retry-After header if provided.

Pagination

  • FastField APIs return paginated results using page and pageSize query parameters. Include these parameters in GET requests and iterate until the response indicates no further pages (e.g., empty nextPage token or hasMore flag).

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


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

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