openapi-zod-client

Generates a zodios (typescript http client with zod validation) from a (json/yaml) OpenAPI spec (or just use the generated schemas/endpoints/etc !)

• can be used programmatically (do w/e you want with the computed schemas/endpoints)

• or used as a CLI (generates a prettier .ts file with deduplicated variables when pointing to the same schema/$ref)

• client typesafety and runtime validation using zodios

• tested (using vitest) against official OpenAPI specs samples

Why this exists

Sometimes you don't have control on your API, maybe you need to consume APIs from other teams (who might each use a different language/framework), you only have their Open API spec as source of truth, then this might help 😇

You could use openapi-zod-client to automate the API integration part (doesn't matter if you consume it in your front or back-end, zodios is agnostic) on your CI and just import the generated api client

Comparison vs tRPC zodios ts-rest etc

If you do have control on your API/back-end, you should probably use a RPC-like solution like tRPC, zodios or ts-rest instead of this.

Comparison vs typed-openapi

• openapi-zod-client is a CLI that generates a zodios API client (typescript http client with zod validation), currently using axios as http client
• typed-openapi is a CLI/library that generates a headless (bring your own fetcher : fetch, axios, ky, etc...) Typescript API client from an OpenAPI spec, that can output schemas as either just TS types (providing instant suggestions in your IDE) or different runtime validation schemas (zod, typebox, arktype, valibot, io-ts, yup)

Usage

with local install:

• pnpm i -D openapi-zod-client
• pnpm openapi-zod-client "./input/file.json" -o "./output/client.ts"

or directly (no install)

• pnpx openapi-zod-client "./input/file.yaml" -o "./output/client.ts"

auto-generated doc

https://paka.dev/npm/openapi-zod-client

CLI

1openapi-zod-client/1.15.0
2
3Usage:
4  $ openapi-zod-client <input>
5
6Commands:
7  <input>  path/url to OpenAPI/Swagger document as json/yaml
8
9For more info, run any command with the `--help` flag:
10  $ openapi-zod-client --help
11
12Options:
13  -o, --output <path>               Output path for the zodios api client ts file (defaults to `<input>.client.ts`)
14  -t, --template <path>             Template path for the handlebars template that will be used to generate the output
15  -p, --prettier <path>             Prettier config path that will be used to format the output client file
16  -b, --base-url <url>              Base url for the api
17  --no-with-alias                   With alias as api client methods (default: true)
18  -a, --with-alias                  With alias as api client methods (default: true)
19  --api-client-name <name>          when using the default `template.hbs`, allow customizing the `export const {apiClientName}`
20  --error-expr <expr>               Pass an expression to determine if a response status is an error
21  --success-expr <expr>             Pass an expression to determine which response status is the main success status
22  --media-type-expr <expr>          Pass an expression to determine which response content should be allowed
23  --export-schemas                  When true, will export all `#/components/schemas`
24  --implicit-required               When true, will make all properties of an object required by default (rather than the current opposite), unless an explicitly `required` array is set
25  --with-deprecated                 when true, will keep deprecated endpoints in the api output
26  --with-description                when true, will add z.describe(xxx)
27  --with-docs                       when true, will add jsdoc comments to generated types 
28  --group-strategy                  groups endpoints by a given strategy, possible values are: 'none' | 'tag' | 'method' | 'tag-file' | 'method-file'
29  --complexity-threshold            schema complexity threshold to determine which one (using less than `<` operator) should be assigned to a variable
30  --default-status                  when defined as `auto-correct`, will automatically use `default` as fallback for `response` when no status code was declared
31  --all-readonly                    when true, all generated objects and arrays will be readonly
32  --export-types                    When true, will defined types for all object schemas in `#/components/schemas`
33  --additional-props-default-value  Set default value when additionalProperties is not provided. Default to true. (default: true)
34  --strict-objects                  Use strict validation for objects so we don't allow unknown keys. Defaults to false. (default: false)
35  -v, --version                     Display version number
36  -h, --help                        Display this message

Customization

You can pass a custom handlebars template and/or a custom prettier config with something like:

pnpm openapi-zod-client ./example/petstore.yaml -o ./example/petstore-schemas.ts -t ./example/schemas-only.hbs -p ./example/prettier-custom.json --export-schemas, there is an example of the output here

When using the CLI

• --success-expr is bound to isMainResponseStatus
• --error-expr is bound to isErrorStatus

You can pass an expression that will be safely evaluted (thanks to whence) and works like validateStatus from axios to determine which OpenAPI ResponseItem should be picked as the main one for the ZodiosEndpoint["response"] and which ones will be added to the ZodiosEndpoint["errors"] array.

Exemple: --success-expr "status >= 200 && status < 300"

Tips

• You can omit the -o (output path) argument if you want and it will default to the input path with a .ts extension: pnpm openapi-zod-client ./input.yaml will generate a ./input.yaml.ts file

• Since internally we're using swagger-parser, you should be able to use an URL as input like this: pnpx openapi-zod-client https://raw.githubusercontent.com/OAI/OpenAPI-Specification/main/examples/v3.0/petstore.yaml -o ./petstore.ts

• Also, multiple-files-documents ($ref pointing to another file) should work out-of-the-box as well, but if it doesn't, maybe dereferencing your document before passing it to openapi-zod-client could help

• If you only need a few portions of your OpenAPI spec (i.e. only using a few endpoints from the GitHub REST API OpenAPI Spec), consider using openapi-endpoint-trimmer to trim unneeded paths from your spec first. It supports prefix-based omitting of paths, helping significantly cut down on the length of your output types file, which generally improves editor speed and compilation times.

Example

• You can check an example input (the petstore example when you open/reset editor.swagger.io) and output
• there's also an example of a programmatic usage
• or you can check the tests in the src folder which are mostly just inline snapshots of the outputs

tl;dr

input:

1openapi: "3.0.0"
2info:
3    version: 1.0.0
4    title: Swagger Petstore
5    license:
6        name: MIT
7servers:
8    - url: http://petstore.swagger.io/v1
9paths:
10    /pets:
11        get:
12            summary: List all pets
13            operationId: listPets
14            tags:
15                - pets
16            parameters:
17                - name: limit
18                  in: query
19                  description: How many items to return at one time (max 100)
20                  required: false
21                  schema:
22                      type: integer
23                      format: int32
24            responses:
25                "200":
26                    description: A paged array of pets
27                    headers:
28                        x-next:
29                            description: A link to the next page of responses
30                            schema:
31                                type: string
32                    content:
33                        application/json:
34                            schema:
35                                $ref: "#/components/schemas/Pets"
36                default:
37                    description: unexpected error
38                    content:
39                        application/json:
40                            schema:
41                                $ref: "#/components/schemas/Error"
42        post:
43            summary: Create a pet
44            operationId: createPets
45            tags:
46                - pets
47            responses:
48                "201":
49                    description: Null response
50                default:
51                    description: unexpected error
52                    content:
53                        application/json:
54                            schema:
55                                $ref: "#/components/schemas/Error"
56    /pets/{petId}:
57        get:
58            summary: Info for a specific pet
59            operationId: showPetById
60            tags:
61                - pets
62            parameters:
63                - name: petId
64                  in: path
65                  required: true
66                  description: The id of the pet to retrieve
67                  schema:
68                      type: string
69            responses:
70                "200":
71                    description: Expected response to a valid request
72                    content:
73                        application/json:
74                            schema:
75                                $ref: "#/components/schemas/Pet"
76                default:
77                    description: unexpected error
78                    content:
79                        application/json:
80                            schema:
81                                $ref: "#/components/schemas/Error"
82components:
83    schemas:
84        Pet:
85            type: object
86            required:
87                - id
88                - name
89            properties:
90                id:
91                    type: integer
92                    format: int64
93                name:
94                    type: string
95                tag:
96                    type: string
97        Pets:
98            type: array
99            items:
100                $ref: "#/components/schemas/Pet"
101        Error:
102            type: object
103            required:
104                - code
105                - message
106            properties:
107                code:
108                    type: integer
109                    format: int32
110                message:
111                    type: string

output:

1import { makeApi, Zodios } from "@zodios/core";
2import { z } from "zod";
3
4const Pet = z.object({ id: z.number().int(), name: z.string(), tag: z.string().optional() });
5const Pets = z.array(Pet);
6const Error = z.object({ code: z.number().int(), message: z.string() });
7
8export const schemas = {
9    Pet,
10    Pets,
11    Error,
12};
13
14const endpoints = makeApi([
15    {
16        method: "get",
17        path: "/pets",
18        requestFormat: "json",
19        parameters: [
20            {
21                name: "limit",
22                type: "Query",
23                schema: z.number().int().optional(),
24            },
25        ],
26        response: z.array(Pet),
27    },
28    {
29        method: "post",
30        path: "/pets",
31        requestFormat: "json",
32        response: z.void(),
33    },
34    {
35        method: "get",
36        path: "/pets/:petId",
37        requestFormat: "json",
38        parameters: [
39            {
40                name: "petId",
41                type: "Path",
42                schema: z.string(),
43            },
44        ],
45        response: Pet,
46    },
47]);
48
49export const api = new Zodios(endpoints);
50
51export function createApiClient(baseUrl: string) {
52    return new Zodios(baseUrl, endpoints);
53}

TODO

• handle OA prefixItems -> output z.tuple
• rm unused (=never referenced) variables from output

Caveats

NOT tested/expected to work with OpenAPI before v3, please migrate your specs to v3+ if you want to use this

You can do so by using the official Swagger Editor: https://editor.swagger.io/ using the Edit -> Convert to OpenAPI 3.0 menu

Contributing:

• A .node-version file has been provided in the repository root, use your preferred Node.js manager which supports the standard to manage the development Node.js environment
• The monorepo supports corepack, follow the linked instructions to locally install the development package manager (i.e. pnpm)

1> pnpm install
2> pnpm test

Assuming no issue were raised by the tests, you may use pnpm dev to watch for code changes during development.

If you fix an edge case please make a dedicated minimal reproduction test in the tests folder so that it doesn't break in future versions

Make sure to generate a changeset before submitting your PR.