JustCall Python API Docs | dltHub

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

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JustCall is a cloud phone and contact center platform providing REST APIs for managing voice calls, SMS and MMS messages, contacts, and phone numbers. The REST API base URL is https://api.justcall.io/v2.1 and all requests require an Authorization header containing the API key and secret separated by a colon.

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 JustCall data in under 10 minutes.


What data can I load from JustCall?

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

ResourceEndpointMethodData selectorDescription
calls/v2.1/callsGETRetrieve all calls
contacts/v2.1/contactsGETRetrieve all contacts
users/v2.1/usersGETRetrieve all users
texts/v2.1/textsGETRetrieve all SMS
voice_agents/v2.1/voice_agentsGETList all AI agents

How do I authenticate with the JustCall API?

Authentication is performed by sending the API key and API secret in the Authorization header, formatted as 'api_key

'.

1. Get your credentials

To obtain your JustCall API credentials, follow these steps in the JustCall web dashboard: 1. Sign in to your JustCall account. 2. Click on your profile icon (usually located in the bottom-left or top-right of the navigation bar). 3. Select 'APIs and Webhooks' from the menu. 4. In the 'API Credentials' section, you will find your 'API Key' and 'API Secret'. 5. Use the provided copy icons to store these securely. Note that the API Secret may be hidden by default; click the 'eye' icon to reveal it. API access requires a Team plan or higher.

2. Add them to .dlt/secrets.toml

[sources.justcall_source] api_key = "REPLACE_ME"

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 JustCall 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 justcall_pipeline.py

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

Pipeline justcall_pipeline load step completed in 0.26 seconds 1 load package(s) were loaded to destination duckdb and into dataset justcall_data The duckdb destination used duckdb:/justcall.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 calls and contacts from the JustCall 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 justcall_source(api_key=dlt.secrets.value): config: RESTAPIConfig = { "client": { "base_url": "https://api.justcall.io/v2.1", "auth": {"type": "http_basic", "username": "REPLACE_ME", "password": api_key}, }, "resources": [ {"name": "calls", "endpoint": {"path": "v2.1/calls"}}, {"name": "contacts", "endpoint": {"path": "v2.1/contacts"}} ], } yield from rest_api_resources(config) def get_data() -> None: pipeline = dlt.pipeline( pipeline_name="justcall_pipeline", destination="duckdb", dataset_name="justcall_data", ) load_info = pipeline.run(justcall_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("justcall_pipeline").dataset() sessions_df = data.calls.df() print(sessions_df.head())

SQL (DuckDB example):

SELECT * FROM justcall_data.calls LIMIT 10;

In a marimo or Jupyter notebook:

import dlt data = dlt.pipeline("justcall_pipeline").dataset() data.calls.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 JustCall 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.


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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