OpenRPCExtensions

SDK Method Names

Use x-fern-sdk-method-name to customize SDK method names for JSON-RPC methods

By default, Fern generates SDK method names based on your OpenRPC method names. You can override this behavior using the x-fern-sdk-method-name extension.

Customize method names

Use x-fern-sdk-method-name to specify custom method names for your JSON-RPC methods:

openrpc.yml
1methods:
2  - name: user.getById
3    summary: Get user by ID
4    x-fern-sdk-method-name: getUser
5    params:
6      - name: id
7        schema:
8          type: string
9        required: true
10    result:
11      name: user
12      schema:
13        $ref: '#/components/schemas/User'
14  - name: order.createNew
15    summary: Create a new order
16    x-fern-sdk-method-name: create
17    params:
18      - name: orderData
19        schema:
20          $ref: '#/components/schemas/CreateOrderRequest'
21        required: true
22    result:
23      name: order
24      schema:
25        $ref: '#/components/schemas/Order'

This will generate SDK methods like:

1// Instead of client.user.getById()
2const user = await client.user.getUser({ id: "user_123" });
3
4// Instead of client.order.createNew()
5const order = await client.order.create({ orderData: {...} });

Method naming conventions

Follow these conventions when naming SDK methods:

CRUD operations

Use standard CRUD naming:

openrpc.yml
1methods:
2  - name: user.createUser
3    summary: Create a new user
4    x-fern-sdk-method-name: create
5    # Generates: client.user.create()
6    
7  - name: user.getUserById
8    summary: Get user by ID
9    x-fern-sdk-method-name: get
10    # Generates: client.user.get()
11    
12  - name: user.updateUser
13    summary: Update user information
14    x-fern-sdk-method-name: update
15    # Generates: client.user.update()
16    
17  - name: user.deleteUser
18    summary: Delete a user
19    x-fern-sdk-method-name: delete
20    # Generates: client.user.delete()

List operations

Use descriptive names for list operations:

openrpc.yml
1methods:
2  - name: user.getAllUsers
3    summary: Get all users
4    x-fern-sdk-method-name: list
5    # Generates: client.user.list()
6    
7  - name: user.searchUsers
8    summary: Search for users
9    x-fern-sdk-method-name: search
10    # Generates: client.user.search()
11    
12  - name: order.getUserOrders
13    summary: Get orders for a user
14    x-fern-sdk-method-name: listByUser
15    # Generates: client.order.listByUser()

Action operations

Use action-oriented names:

openrpc.yml
1methods:
2  - name: email.sendNotification
3    summary: Send email notification
4    x-fern-sdk-method-name: send
5    # Generates: client.email.send()
6    
7  - name: payment.processPayment
8    summary: Process a payment
9    x-fern-sdk-method-name: process
10    # Generates: client.payment.process()
11    
12  - name: cache.invalidateCache
13    summary: Invalidate cache entries
14    x-fern-sdk-method-name: invalidate
15    # Generates: client.cache.invalidate()

Language-specific method names

You can specify different method names for different programming languages:

openrpc.yml
1methods:
2  - name: user.getUserPreferences
3    summary: Get user preferences
4    x-fern-sdk-method-name:
5      python: get_preferences
6      typescript: getPreferences
7      go: GetPreferences
8      java: getPreferences
9      csharp: GetPreferences
10    params:
11      - name: userId
12        schema:
13          type: string
14        required: true
15    result:
16      name: preferences
17      schema:
18        $ref: '#/components/schemas/UserPreferences'

Namespaced method names

For methods with namespace prefixes, customize the final method name:

openrpc.yml
1methods:
2  - name: analytics.track.pageView
3    summary: Track page view event
4    x-fern-sdk-method-name: trackPageView
5    params:
6      - name: eventData
7        schema:
8          $ref: '#/components/schemas/PageViewEvent'
9        required: true
10  - name: analytics.track.conversion
11    summary: Track conversion event
12    x-fern-sdk-method-name: trackConversion
13    params:
14      - name: eventData
15        schema:
16          $ref: '#/components/schemas/ConversionEvent'
17        required: true

Generates:

1await client.analytics.trackPageView({ eventData: {...} });
2await client.analytics.trackConversion({ eventData: {...} });

Notification method names

For notification methods (one-way calls), use appropriate naming:

openrpc.yml
1methods:
2  - name: log.recordError
3    summary: Record an error event
4    x-fern-sdk-method-name: logError
5    params:
6      - name: errorData
7        schema:
8          $ref: '#/components/schemas/ErrorData'
9        required: true
10    # No result - this is a notification
11  - name: metrics.incrementCounter
12    summary: Increment a metric counter
13    x-fern-sdk-method-name: increment
14    params:
15      - name: metric
16        schema:
17          type: string
18        required: true
19      - name: value
20        schema:
21          type: number
22          default: 1
23    # No result - this is a notification

Async method naming

For methods that return promises or futures, consider async naming:

openrpc.yml
1methods:
2  - name: report.generateReport
3    summary: Generate a report (long-running)
4    x-fern-sdk-method-name: generateAsync
5    params:
6      - name: reportConfig
7        schema:
8          $ref: '#/components/schemas/ReportConfig'
9        required: true
10    result:
11      name: jobId
12      schema:
13        type: string
14        description: Job ID for tracking report generation

This ensures method names follow the conventions of each target language while maintaining clear and intuitive APIs for developers.