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Async Webhook Delivery Engine

PHP
Symfony
Webhooks
Event-driven
Backend

Resilient webhook delivery engine with circuit breaker, exponential backoff, and per-client-domain rate limiting.

event POST /hook Symfony Messenger circuit breaker Redis SETNX lock target webhook DLQ · backoff · 429 Async Webhook Engine Symfony 7 · Redis · PHPStan 9

About the project

A webhook delivery engine designed to process asynchronous events under strict rate limits and failure conditions. The system provides high throughput while remaining resilient to remote endpoint errors.

Repository: github.com/kopolot/example-async-weebhook-engine

Key implementations

Failure resilience

Circuit Breaker pattern to pause deliveries to unavailable endpoints, combined with Exponential Backoff Retries and Dead Letter Queue (DLQ) routing for unrecoverable payloads.

Concurrency and rate limiting

Atomic Redis locks (SETNX) enforcing concurrency limits per client domain, preventing flooding of target servers and handling HTTP 429 backpressure.

Code quality

Strict typing (declare(strict_types=1)), PHPStan Level 9, automated PHPUnit test suite, and GitHub Actions CI pipeline.