Lob OpenAPI v3 Specification
June 1, 2026 · View on GitHub
What is this project?
We're writing an OpenAPI v3 authored specification for the current Lob API. This repo contains the spec as well as a growing set of tooling for working with OpenAPI v3 specs.
Contributing
Design
Our spec is a multifile spec organized semantically, by resource, instead of syntactically, by OpenAPI element. Organizing the spec semantically reduces cognitive friction, helping developers reason from interaction (endpoints) to data (and process) design. As developers from multiple teams work with the spec, the design surfaces business semantics rather than presenting the canonical wall-o-yaml (or json-schema) that typifies the traditional API spec.
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├── lob-api-public.yml # base file (metadata, tags, servers, ...)
├── resources
│ ├── postcards # elements specific to postcards
│ │ ├── postcards.yml # operations on /postcards
│ │ ├── postcard.yml # operations on /postcards/{id}
│ │ ├── attributes
│ │ │ └── ...
│ │ ├── models
│ │ │ └── postcard.yml
│ │ └── responses
│ │ ├── postcard.yml
│ │ └── all_postcards.yml
│ └── letters # elements specific to letters
│ ├── letters.yml # operations on /letters
│ ├── letter.yml # operations on /letters/{id}
│ └── ...
├── shared # elements used by multiple resources
│ ├── attributes # properties not of type `object`
│ ├── headers
│ ├── models # properties of type `object`
│ ├── parameters
│ └── responses
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├── actions # private github actions or resources needed by actions
│ ├── contract_tests
│ └── redoc
├── dist # contents created during CD by github actions
└── tests # contract tests
├── setup.js # contract test framework
├── addresses_test.js # tests for addresses resource
├── us_verifications.test.js # tests for us_verifications resource...
└── ...
OpenAPI Style Guide and linting
Our OpenAPI style guide is an extension of Spectral's OpenAPI ruleset. Spectral's ruleset goes beyond the OpenAPI v3 standard to incorporate a recommended set of best practices.
Spectral runs in CI on push and pull request.
Readability
We use Prettier to ensure that all our code follows a consist format for
maximum readability. If you have been given the green light to create a PR, you can run prettier as
you work via npm run pretty and/or through editor integrations for many major editors.
In addition, a pre-commit githook runs prettier --check . (the same check run in CI).
OAS v3.1 compatibility
On February 15, 2021, the OpenAPI Initiative published OpenAPI v3.1. OAS 3.1 includes many extremely useful changes, including full JSON schema compatibility and the ability to extend discriminators with specification extensions.
We will move to v3.1 as soon as is practical. In the meantime, we're working to minimize the changes we'll need to make.
Previewing changes
If you've changed the css and js, you need to run npm run build to
create the uglified js and css files that your local docs will depend on.
The new chunks will show up in docs/chunks.
You can then generate documentation for the API from the spec by running
npm run redoc, which uses redoc. The
generated docs will apppear in docs/index.html. Then you can point
your browser to the absolute path of that file to review your local
version of the docs.
Contributing to this repo
When you try to commit your changes, a pre-commit hook with run. It will:
- Check linting
- Run tests
If your tests fail, it is because your hook is looking for specific keys in your environment. In order to commit your changes and test on Github, you will need to pass --no-verify after your commit.
E2E Testing
You can run the currently available end-to-end tests with the command npm run docsTest.
This builds docs locally and runs Cypress against the generated output.
Use npm run docsTest:deployed to run the same prerendered docs smoke tests against the GitHub Pages deployment.
Bundled spec
A lot of tooling for working with OpenAPI specs does not support the full
specification. In particular, many tools do not support multiple file specs.
We maintain a single file 'bundled' version of the spec for use with such
tools. The bundled version is generated as part of CI/CD, and can be found
on github at dist/lob-api-bundled.yml on the deployment branch.
Postman Collection
You can generate a big JSON representing a Postman Collection for this spec
locally with npm run postman. The resulting dist/lob-api-postman.json can be
imported into Postman so that you can get started on making requests to Lob API.
Here's a video tutorial on that.
How to bump version
Run npm run bump-version <<newversion> | major | minor | patch>
When bumping the version there are three key areas where the version should be bumped. Verify that these versions are updated after running the script
package.jsonpackage-lock.jsonlob-api-public.yml
Ensure you run npm run bundle && npm run pretty && npm run redoc to actually appply changes to package and package-lock. You will need to change lob-api-public.yml manually.
Deployment
The last step is to create a new release. Create a new tag to match the version you're deploying and provide a brief description. You can monitor the deployment at the Deploy to Netlify Action.