SSRF Protection
Sandboxed execution blocking private internal subnets, keeping webhooks protected from redirect and DNS rebinding SSRF exploits.
Webhook recovery platform
Dead Letter relays every webhook, retries every failure, and replays it when your server recovers. No payloads lost. No glue code.
Runs on its own infrastructure, so your outages can't take our queue down.
No credit card required · 100k events/mo free
ENDPOINT /ingest/acme-payments STATUS DELIVERED ✓ ATTEMPTS 3 of 5 LATENCY 240ms SIGNATURE verified NEXT —
From a webhook source to a recovered delivery, every transition has an owner and a record.
Point your provider's webhook URL at your deadletter.io slug.
We sign, validate, and queue the payload durably.
We POST to your destination with retry and exponential backoff.
Inspect, replay, or reroute anything that fails.
When your server goes down, webhooks don't have to be lost. See how Dead Letter catches, queues, and replays every payload automatically.
A payment provider fires a webhook event. Dead Letter receives and acknowledges it immediately.
Test your payload signatures securely in your browser.
Dead Letter secures your webhooks by signing them with a unique secret key.
Verify your backend code by generating identical HMAC-SHA256 signatures here.
Why a secret?Webhook URLs are public. To prove a webhook genuinely came from Dead Letter (and not a malicious actor), we generate this signature using a secret password known only to you. Your server re-calculates the signature and blocks the request if it doesn't match perfectly.
Built from scratch to handle millions of payloads with absolute security.
Sandboxed execution blocking private internal subnets, keeping webhooks protected from redirect and DNS rebinding SSRF exploits.
Fine-tune automatic retry triggers, backoff algorithms, and jitter constants to optimize traffic without overloading database structures.
Generate secure write-only tokens to interact programmatically with retry states, endpoints configuration, and delivery logs.
Ensure data integrity with HMAC SHA-256 signatures attached to every payload, preventing spoofing and malicious requests.
Monitor live webhooks and failures instantly through our high-performance Server-Sent Events (SSE) streaming architecture.
Receive instant notifications in Slack or Discord whenever a webhook exhausts all retries and transitions to a permanent failure.
Select the pricing tier that scales with your webhook delivery volume and security requirements.
99.99% ingestion uptime · cancel anytime
Ideal for local development and minor webhook integrations.
$0forever
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Perfect for scaling startups and production webhook traffic.
$29/month
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Built for mission-critical services requiring absolute reliability.
$299/month
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