Alchemy Ethereum Python API Docs | dltHub

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

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Alchemy provides a blockchain developer platform with Ethereum JSON-RPC and Data APIs for accessing on-chain data and managing transactions. The REST API base URL is https://eth-mainnet.g.alchemy.com/v2 and all requests require an Alchemy API key, which can be passed as a Bearer token in the Authorization header or as a path parameter in the URL.

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 Alchemy Ethereum data in under 10 minutes.


What data can I load from Alchemy Ethereum?

Here are some of the endpoints you can load from Alchemy Ethereum:

ResourceEndpointMethodData selectorDescription
token_balancesalchemy_getTokenBalancesPOSTtokenBalancesFetches ERC20 token balances for a wallet address.
nft_balancesalchemy_getNftsPOSTownedNftsFetches NFTs owned by a wallet address.
asset_transfersalchemy_getAssetTransfersPOSTtransfersFetches historical token and NFT transfers for an address.
block_dataeth_getBlockByNumberPOSTReturns full block information by block number.
account_balanceeth_getBalancePOSTReturns the ETH balance for a given address at a block.

How do I authenticate with the Alchemy Ethereum API?

Alchemy supports authentication via an Authorization header using the 'Bearer' token format (e.g., 'Authorization: Bearer <your_api_key>'), or by including the API key directly in the URL path. For enhanced security, using the Authorization header is recommended over URL-based authentication.

1. Get your credentials

  1. Sign in to your Alchemy Dashboard account at dashboard.alchemy.com.\n2. Navigate to the Apps section from the sidebar.\n3. Click the Create App button to create a new application.\n4. Provide a name and optional description for your application.\n5. Select 'Ethereum' as the chain and choose your desired network (e.g., Mainnet or Sepolia).\n6. Once created, click on your app in the list to view its details.\n7. Copy the API Key shown in the top-right corner of the app details page, or copy the full API URL (HTTPS or WebSocket) from the Endpoints tab.

2. Add them to .dlt/secrets.toml

[sources.alchemy_ethereum_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 Alchemy Ethereum 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 alchemy_ethereum_pipeline.py

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

Pipeline alchemy_ethereum_pipeline load step completed in 0.26 seconds 1 load package(s) were loaded to destination duckdb and into dataset alchemy_ethereum_data The duckdb destination used duckdb:/alchemy_ethereum.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 v1/getNFTs and nft/v3/getNFTMetadata from the Alchemy Ethereum 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 alchemy_ethereum_source(api_key=dlt.secrets.value): config: RESTAPIConfig = { "client": { "base_url": "https://eth-mainnet.g.alchemy.com/v2", "auth": {"type": "bearer", "token": api_key}, }, "resources": [ {"name": "token_balances", "endpoint": {"path": "v2/{apiKey}", "data_selector": "tokenBalances"}}, {"name": "nft_balances", "endpoint": {"path": "v2/{apiKey}", "data_selector": "ownedNfts"}} ], } yield from rest_api_resources(config) def get_data() -> None: pipeline = dlt.pipeline( pipeline_name="alchemy_ethereum_pipeline", destination="duckdb", dataset_name="alchemy_ethereum_data", ) load_info = pipeline.run(alchemy_ethereum_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("alchemy_ethereum_pipeline").dataset() sessions_df = data.token_balances.df() print(sessions_df.head())

SQL (DuckDB example):

SELECT * FROM alchemy_ethereum_data.token_balances LIMIT 10;

In a marimo or Jupyter notebook:

import dlt data = dlt.pipeline("alchemy_ethereum_pipeline").dataset() data.token_balances.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 Alchemy Ethereum 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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