Error Handling

The SDK throws typed error classes for different failure scenarios, making it simple to handle specific error conditions in your application.

Error Classes

All API errors extend the base FellohError class. You can catch the base class or target specific error types using instanceof.

Error Class	Status Code	Description
`FellohAuthenticationError`	401	Invalid API credentials or expired token
`FellohForbiddenError`	403	Insufficient permissions for the requested action
`FellohNotFoundError`	404	The requested resource does not exist
`FellohValidationError`	422	Request body failed validation — check `errors` for field-level details
`FellohRateLimitError`	429	API rate limit exceeded
`FellohServerError`	5xx	Server error — the SDK automatically retries these
`FellohNetworkError`	—	Network failure (timeout, DNS, connection refused) — also retried automatically

The FellohError Object

Every error thrown by the SDK includes structured data about the failure.

Properties

Name
message
Type
string
Description
A human-readable error message.
Name
statusCode
Type
integer
Description
The HTTP status code. 0 for network-level failures.
Name
errors
Type
array
Description
An array of structured error objects returned by the API. Each includes title, message, code, type, and documentation_url.
Name
meta
Type
object
Description
Response metadata including request_id — useful for debugging with Felloh support.

Error Properties

import {
  FellohError,
  FellohNotFoundError,
  FellohValidationError,
} from '@felloh-org/node-sdk';

try {
  await client.bookings.get('non-existent-id');
} catch (err) {
  if (err instanceof FellohNotFoundError) {
    console.log('Booking not found');
  }

  if (err instanceof FellohValidationError) {
    // Inspect field-level validation errors
    for (const error of err.errors) {
      console.log(`${error.title}: ${error.message}`);
    }
  }

  if (err instanceof FellohError) {
    console.log(err.statusCode);  // HTTP status code
    console.log(err.errors);      // API error details
    console.log(err.meta);        // Includes request_id
  }
}

Automatic Retries

The SDK automatically retries requests that fail with a 5xx server error or a network error. Retries use exponential backoff with a maximum of maxRetries attempts (default: 2).

You can configure this when creating the client:

Configuring Retries

const client = new FellohClient({
  publicKey: 'your-public-key',
  privateKey: 'your-private-key',
  maxRetries: 3,     // retry up to 3 times on 5xx/network errors
  timeout: 15000,    // 15 second timeout per request
});