Load Blockchain data to DuckDB

Blockchain.com Exchange REST API provides functionality for receiving real-time market data, requesting balance information, and performing trades. Everything needed to build a working Blockchain → DuckDB pipeline is on this page: the API's base URL, authentication, endpoints, pagination and incremental field — plus a prompt that hands the whole job to your coding agent.

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Build your Blockchain to DuckDB pipeline

Paste this prompt into Claude, Codex, or Cursor. The agent does the rest.

PromptCopy prompt
Run uvx dlthub-init@latest to build a pipeline from Blockchain to DuckDB and run it on dltHub

That scaffolds a dltHub workspace and installs the dltHub AI harness — the project rules, the secrets-management skill, and the dlt MCP server your agent needs to work safely. From there it reads the Blockchain API, proposes the endpoints to load, then writes, runs and validates the pipeline while you review rather than type. Credentials are inspected through MCP tools, so your agent never reads secrets.toml itself. How the LLM-native workflow works →

Prefer to write it yourself? Every fact the agent uses is below.

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Blockchain API at a glance

These values come from the Blockchain API reference — the authoritative source if anything here looks out of date.

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How do I authenticate with the Blockchain API?

All authenticated requests to the Blockchain.com Exchange REST API require the API key to be passed in the X-API-Token header.

1. Get your credentials

1. Log in to your Blockchain.com Exchange account. 2. Navigate to the API settings section from the account drop-down menu. 3. Fill out the form provided to create a new API key. 4. Once generated, your API key (and API secret, if applicable) will be displayed. Ensure you copy and store the API secret securely as it will only be shown once. 5. Verify the API key via email before it can be used.

2. Add them to .dlt/secrets.toml

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[sources.blockchain_source]
api_token = "your_api_key_here"

dlt reads this file automatically at runtime. With the harness, the setup-secrets skill prompts you for the values and never handles the raw credential in chat. For production, see setting up credentials with dlt.

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What Blockchain data can I load into DuckDB?

These are the Blockchain endpoints dlt can load into DuckDB:

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How do I load only new Blockchain records?

Blockchain exposes cursor on v1/allchains/transactions, so dlt can request only the records that changed since the last run. Set it as the cursor_path and dlt tracks the high-water mark for you between runs.

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{"name": "transactions", "endpoint": {
    "path": "v1/allchains/transactions",
    "data_selector": "items",
    "incremental": {"cursor_path": "cursor", "initial_value": "2024-01-01T00:00:00Z"},
}}

On the first run dlt loads everything from initial_value; on every run after that it requests only what changed and appends with write_disposition="merge" if you set a primary key. See incremental loading.

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What does the generated Blockchain pipeline look like?

A standard dlt REST API pipeline — the same code you would write by hand, loading https://api.blockchain.com/v3/exchange/l2 and https://api.blockchain.com/v3/exchange/orders from the Blockchain API into DuckDB:

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

@dlt.source
def blockchain_source(api_key=dlt.secrets.value):
    config: RESTAPIConfig = {
        "client": {
            "base_url": "https://api.blockchain.com/v3/exchange",
            "auth": {"type": "api_key", "api_key": api_key, "name": "X-API-Token", "location": "header"},
        },
        "resources": [
            {"name": "transactions", "endpoint": {"path": "v1/allchains/transactions", "data_selector": "items"}},
            {"name": "accounts", "endpoint": {"path": "accounts", "data_selector": "items"}}
        ],
    }
    yield from rest_api_resources(config)


def load_blockchain_to_duckdb() -> None:
    pipeline = dlt.pipeline(
        pipeline_name="blockchain_pipeline",
        destination="duckdb",
        dataset_name="blockchain_data",
    )
    load_info = pipeline.run(blockchain_source())
    print(load_info)


if __name__ == "__main__":
    load_blockchain_to_duckdb()

Run it with python blockchain_pipeline.py. The agent iterates on this until it loads cleanly — you review and approve, rather than write it from scratch.

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How do I query Blockchain data in DuckDB?

dlt creates one table per resource. Query the loaded data with Python or SQL — or ask your agent to, through the MCP server's execute_sql_query tool.

Python (pandas DataFrame):

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import dlt

data = dlt.pipeline("blockchain_pipeline").dataset()
df = data.transactions.df()
print(df.head())

SQL:

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SELECT * FROM blockchain_data.transactions LIMIT 10;

See querying your data with dataset and exploring it in marimo notebooks.

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How do I deploy the Blockchain to DuckDB pipeline in production?

The pipeline runs locally, which is ideal for prototyping and one-off analysis. When you need it on a schedule, monitored on every load, and shared with your team, deploy the same dlt code on the dltHub platform — no infrastructure to maintain. The prompt above already ends with "run it on dltHub", so your agent can take it there directly.

• Deploy & schedule — run the pipeline as a managed job with automatic retries.
• Monitor — observable job queues, alerting, and load metrics for every run.
• Transform — promote raw Blockchain loads into governed, documented models.
• Visualize & share — explore data in notebooks and publish live dashboards instead of static screenshots.

Book a demo →

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What other destinations can I load Blockchain data to?

dlt loads into any of these — only the destination argument changes:

Set dlt.pipeline(destination="snowflake") and add credentials in .dlt/secrets.toml. On the dltHub platform the same pipeline runs against a managed Iceberg lakehouse. See the full destinations list.

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Next steps

• Ready for production? Book a demo of the dltHub platform →
• dlt LLM-native workflow docs
• REST API source reference
• Join the dlt community on Slack