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GeneratorsPython

Generating an SDK

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Generate a Python SDK by following the instructions on this page.

Generate a Python SDK
Generate a Python SDK with Fern. Follow the [Python SDK quickstart](https://buildwithfern.com/learn/sdks/generators/python/quickstart.md) step by step.
1

Install the Fern CLI

npm install -g fern-api
2

Initialize the fern folder

Initialize the fern folder with your existing OpenAPI specification. Specify your organization name using the --organization flag.

fern init --openapi path/to/openapi.yml \
--organization <YourOrganization>

OpenAPI accepts both JSON and YAML formats.

This creates a fern folder in your current directory.

fern
fern.config.json# root-level configuration
sdk-config.yml# SDK targets and API spec configuration
openapi.yml# copy of a local spec
3

Validate your API definition

Check that your API definition is valid, and fix errors before proceeding:

fern check
4

Add the SDK target

Add a Python target to the targets list in sdk-config.yml:

sdk-config.yml
targets:
  - language: python
    output:
      delivery: files
      path: ../sdks/python

The target uses the newest supported Python generator. To pin a version, set generatorVersion on the target.

5

Generate the SDK

Run the following command to generate your SDK:

fern generate --target python

If you have multiple APIs, use the --api flag to specify the API you want to generate:

fern generate --target python --api your-api-name

The first time you run fern generate, you must log in. Confirm the prompt and choose any of the login methods to authenticate, then generation continues automatically.

fern generate creates a sdks folder in your current directory. The resulting folder structure looks like this:

fern# created by fern init
sdks# created by fern generate --target python
python
__init__.py
client.py
core
imdb# or the name of your API
errors
types
Some files, including pyproject.toml and README.md, are only generated on the Enterprise plan. To get the fully generated SDK, schedule a demo or email us.
6

Set up GitHub repositories

Fern uses a multi-repo structure: your source repository contains the fern/ folder, and each SDK gets its own separate repository.

  1. Create a source repository for your fern/ folder if you don’t have one already (e.g., your-org/your-api-definitions).
  2. Create an SDK repository for your SDK (e.g., your-org/your-api-python-sdk).
  3. Install the Fern GitHub App on both repositories.
7

Publish to PyPI

Follow the Publishing to PyPI guide to configure your package and set up automated publishing via GitHub Actions.