> ## Documentation Index
> Fetch the complete documentation index at: https://docs.indic8.ing/llms.txt
> Use this file to discover all available pages before exploring further.

# Multi-Gateway Ingress

> Sub-2ms webhook processing, deduplication, and atomic schema reconciliation.

Indic8 is engineered to process incoming webhook events from diverse payment processors at high throughput.

## Pipeline Lifecycle

```mermaid theme={null}
sequenceDiagram
    participant Gateway as Billing Provider (e.g. Stripe)
    participant Ingress as Edge Ingress Layer
    participant Queue as Redis Stream / BullMQ
    participant Normalizer as Normalizer Worker
    participant DB as Postgres Ledger
    participant WS as WebSocket Clients

    Gateway->>Ingress: POST Webhook (Payload + Signature)
    Ingress->>Ingress: Verify HMAC Signature
    Ingress->>Ingress: Check Redis Idempotency Key
    Ingress-->>Gateway: 200 OK (Acknowledge < 25ms)
    Ingress->>Queue: Push to Stream
    Queue->>Normalizer: Consume Batch
    Normalizer->>Normalizer: Apply FX & Scrub PII
    Normalizer->>DB: Atomic Insert
    Normalizer->>WS: Broadcast Live Event
```

***

## Key Guarantees

### 1. Sub-25ms Gateway Acknowledgments

Payment providers like Stripe and Lemon Squeezy will disable webhooks if response latencies spike. Indic8 immediately acknowledges receipt with `200 OK` after verifying cryptographic signatures, offloading data persistence to background queues.

### 2. Idempotency and Deduplication

Network retries frequently cause duplicate webhook deliveries. Indic8 derives a composite key:

$\text{Idempotency Key} = \text{SHA256}(\text{provider} + \text{event\_id} + \text{timestamp})$

Any duplicate event received within 48 hours is acknowledged as successful but discarded before ledger mutation.

### 3. Out-of-Order Resolution

Events like `customer.subscription.deleted` can occasionally arrive before `customer.subscription.created` due to network routing anomalies. Indic8 uses optimistic locking and state reconcilers to reconstruct the true chronological state.