HookCastle takes events from your app and delivers them to your customers' endpoints — with retries, exponential backoff, HMAC signatures, and a searchable delivery log. Drop it in, point your webhook URL at us, move on.
EU-hosted · GDPR-friendly · Free tier up to 50,000 events/mo
# queue an event for delivery curl -X POST https://api.hookcastle.com/v1/events \ -H "Authorization: Bearer hc_live_a8f...3c2" \ -H "Content-Type: application/json" \ -d '{ "destination": "https://acme.app/hooks/orders", "payload": { "event": "order.paid", "id": "ord_4912" } }' <- 201 Created { "id": "evt_8a3f4b9c7d", "status": "queued", "attempts": 0, "created_at": "2026-04-30T09:14:22Z" }
Failed deliveries get up to 12 attempts over ~24h with exponential backoff (30s, 2m, 10m, 30m, 1h…). Per-endpoint policy if the default isn't right for you. Nothing is dropped silently.
Every attempt is stored with full request and response (status code, headers, body, latency) for the retention window of your plan. Filter by status, endpoint, or any header. Replay individually or in bulk.
Each endpoint can have its own secret. We sign the body with HMAC-SHA256 and ship the signature in X-HookCastle-Signature. Verifying on the receiving side is six lines in any language.
Already use Stripe / GitHub / Shopify webhooks? Point the destination URL at HookCastle, set us as the relay, and keep your existing signature scheme. We forward intact and add ours.
Configure a max requests-per-second per endpoint so you don't accidentally DDoS your customer's slow webhook receiver. Excess events stay queued, not dropped.
Free tier covers 50K events/month; the Pro plan is €29/mo flat with 1M events. No usage-based surprises. If you outgrow Pro, write us — we'll figure something out before sending an invoice.
You publish events to our API. We queue them, deliver them, retry them, and surface what happened. That's it. Two integration shapes:
HookCastle
relay Existing webhook sourcePOST /v1/events with the destination URL. We take it from there. Your code drops the cron job, the queue table, and the retry loop.direct Native integrationfan-out One event, many endpointsorder.*, another to order.paid only). HookCastle handles delivery and retry independently for each endpoint.Two tiers and a "talk to us" option. Annual billing knocks 15% off — written about in the full pricing page.
For testing, side projects, low-volume use.
For production. Most customers land here.
Higher volume, SSO, custom SLA, DPA.
All plans run on EU infrastructure (Sofia, Bulgaria). VAT charged where applicable. Invoices in EUR.
hookcastle.com was, so here we are.HookCastle was started in 2023 by Claudio Baldinucci after the third time he wrote webhook retry logic at a $dayjob. It's still a small operation — there's no growth team, no SDR, no support tier. If you email hello@hookcastle.com, you're emailing the people who write the code.
If you're evaluating HookCastle for production: ask hard questions, we'd rather you don't sign up than sign up disappointed. More about us →