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Documentation Index

Fetch the complete documentation index at: https://docs.useautumn.com/llms.txt

Use this file to discover all available pages before exploring further.

Autumn’s SDKs include a fail-open mechanism that prevents your application from going down if Autumn is temporarily unreachable. When enabled, critical SDK methods return safe default responses instead of throwing errors.

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Why fail-open?

As a billing engine, Autumn sits in the critical path of your application. If your app calls check() to gate access to a feature, and Autumn is unreachable, that call would throw an error — effectively blocking your users from accessing your product. Fail-open ensures your users are never blocked by an Autumn outage. Usage events may be lost during the outage, but your customers stay unaffected.

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Behavior

Fail-open is enabled by default. When Autumn is unreachable (network errors, timeouts, or server errors returning 5XX status codes), the SDK returns safe defaults:
MethodDefault responseEffect
check(){ allowed: true }Users retain access to features
track(){ value: 0, balance: null }Usage event is silently dropped
customers.getOrCreate()Sentinel customer with id: nullReturns a valid but empty customer object
When fail-open triggers, the SDK logs a prominent error to your console so you’re immediately aware of the issue.

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When fail-open triggers

Fail-open activates when the SDK encounters:
  • Server errors — Autumn returns a 5XX status code (500, 502, 503, etc.)
  • Network failures — DNS resolution failure, connection refused, connection reset
  • Timeouts — The request to Autumn times out
Fail-open does not activate for client errors (4XX). If you receive a 400 (bad request), 401 (unauthorized), or 404 (not found), those errors propagate normally since they indicate a problem with your integration, not an Autumn outage.

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Configuration

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Disabling fail-open

If you prefer strict error handling and want all Autumn errors to propagate: 
import { Autumn } from "@useautumn/sdk";

const autumn = new Autumn({
  secretKey: "sk_...",
  failOpen: false,
});

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Detecting fail-open responses

When check() fails open, the response will have allowed: true with empty values: 
const result = await autumn.check({
  customerId: "cus_123",
  featureId: "messages",
});

// Normal response: allowed is based on actual balance
// Fail-open response: allowed is always true, customerId is ""
When customers.getOrCreate() fails open, the returned customer will have id: null: 
const customer = await autumn.customers.getOrCreate({
  customerId: "cus_123",
});

if (customer.id === null) {
  // Autumn was unreachable, handle gracefully
}

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Console output

When fail-open triggers, you’ll see this in your server logs: 
FATAL AUTUMN ERROR DETECTED; FAILING OPEN; LEARN MORE: https://docs.useautumn.com/docs/fail-open; STATUS PAGE: status.useautumn.com
  Operation: check | Status: 503 | Error: Server error
Monitor your logs for this message. If you see it, check status.useautumn.com for ongoing incidents.

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SDK support

SDKFail-open support
@useautumn/sdk (TypeScript)Supported
autumn-python (Python)Coming soon
autumn-js (framework SDK)Coming soon