Signed, retried, replayable event delivery

Send an event with one API call. Harbor Hooks signs it, delivers it to every subscribed endpoint, retries with exponential backoff for up to 72 hours, and keeps a searchable log you can replay from.

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Delivering for 2,400+ engineering teams

1import { HarborHooks } from "@harborhooks/node";2 3const hooks = new HarborHooks(process.env.HARBORHOOKS_KEY);4 5// Fan out to every subscribed endpoint6const msg = await hooks.events.send({7 type: "invoice.paid",8 payload: { id: "inv_8F2K", amount: 4200 },9 idempotencyKey: "inv_8F2K:paid",10});11 12console.log(msg.id); // "msg_2Qx9Lk"

TerminalOutputzsh$ harborhooks listen --forward localhost:3000✓ Ready · forwarding to localhost:3000/webhooks→ invoice.paid msg_2Qx9Lk 200 38 ms→ customer.updated msg_2Qx9Lm 200 41 ms↻ invoice.paid retry 3/12 200 4m 10s

Sending events in production at

Tallyfox
Brindle Pay
Quillstack
Orbitcart
Ledgerline
Nimbusly
Packetwise
Fernhill

The platform

A delivery team you don't have to hire

Queueing, signing, observability and SDKs, run by people who care about the 0.01%.

One call, every endpoint

Send once. We fan it out to every subscriber.

Uptime SLA on Scale and Enterprise.

8 typed SDKs

Generated from one OpenAPI spec.

Signed and scoped

HMAC signatures, rotating secrets, regional data.

Retried, not dropped

A 503 at 2 a.m. becomes a 200 at 2:04 a.m.

send-webhook.js40 lines

1const crypto = require("crypto");2const fetch = require("node-fetch");3 4async function sendWebhook(url, event, secret) {5 const body = JSON.stringify(event);6 const ts = Math.floor(Date.now() / 1000);7 const sig = crypto.createHmac("sha256", secret)8 .update(`${ts}.${body}`).digest("hex");9 let attempt = 0;10 let delay = 1000;11 while (attempt < 12) {12 try {13 const res = await fetch(url, {14 method: "POST",15 headers: {16 "Content-Type": "application/json",17 "X-Signature": `t=${ts},v1=${sig}`,18 },19 body,20 timeout: 30000,21 });22 if (res.ok) return true;23 if (res.status < 500 && res.status !== 429) {24 await deadLetter(event, res.status);25 return false;26 }27 } catch (err) {28 console.error("attempt", attempt, err);29 }30 attempt++;31 delay = Math.min(delay * 2, 6 * 3600e3);32 const jitter = Math.random() * 250;33 await sleep(delay + jitter);34 }35 await deadLetter(event, "max_retries");36 await alertOncall(url, event.id);37 return false;38}39 40module.exports = { sendWebhook };

Shared debug log

Support and engineering see the same delivery history.

How it works

From first event to production in an afternoon

No queue to run, no cron jobs, no retry table to migrate.

1
Send your events
Install the SDK and call send() wherever your app emits an event. Existing JSON payloads work as they are.
2
Set delivery rules
Pick a region, a retry policy and rate limits per endpoint. Defaults are sensible; every knob is optional.
3
Watch them land
Each delivery shows up in the log with status, latency and the response body. Replay anything that failed.

Pricing

Pay for events, not for retries

Retries, replays and signature checks are always free. You only pay for events you send.

Compare plans
Compare plans	Hobby$0per monthFor side projects and prototypes.Start free	ScaleMost popular$49per monthFor production apps with real customers.Choose Scale	EnterpriseCustomannualFor regulated teams and high volume.Talk to sales
Events per month	50k	1M + $20/M	Custom
Endpoints	3	Unlimited	Unlimited
Delivery log	7 days	30 days	90 days
Regions	us-east	All 6	All 6 + dedicated
Event replay
Uptime SLA		99.99%	99.99% + credits
SSO and SCIM
Support	Community	Email, 1 business day	Slack, 1 hour

Prices in USD, billed monthly. Overage on Scale is $20 per additional million events. Cancel any time.

Testimonials

Engineers who stopped babysitting a queue

Sample reviews written for this template. Replace them with your own.

“A customer's endpoint was down for six hours over a weekend. Every event arrived when it came back, in order. I found out on Monday from the log.”
Grace LiuBackend Engineer
“Signature verification took me ten minutes in Go. Our old setup had a shared secret nobody remembered how to rotate.”
Marcus BellPlatform Lead
“Support can search the delivery log by customer ID and replay events themselves. That used to be an engineering ticket every day.”
Amara NwosuHead of Support
“We needed EU data residency for a bank customer. Switching the workspace to eu-central was a dropdown, not a quarter.”
Jonas LindqvistCTO
“The typed Python SDK caught a renamed field in CI before it reached 1,200 integrations. That alone paid for the year.”
Priya ShahSenior Developer
“Per-endpoint rate limits saved us. One customer's tiny server kept falling over; now we cap them at 5 a second and move on.”
Kenji WatanabeSRE

FAQ

Questions from developers

Something missing? Email us; an engineer answers, usually within a few hours.

What counts as an event?

One API call to send, regardless of how many endpoints it fans out to or how many retries it takes. An event delivered to five subscribers and retried twice is still one event on your bill.

How do retries work?

Any non-2xx response or a timeout after 30 seconds triggers a retry. The default schedule is 12 attempts over 72 hours with jittered exponential backoff. You can shorten it per endpoint, and after the last attempt the event moves to a dead-letter queue you can replay.

How do my customers verify payloads?

Each request includes a signature header with an HMAC-SHA256 of the timestamp and body. Every SDK ships a verify() helper, and the docs include copy-paste snippets for frameworks that don't have an SDK yet.

Where is my data stored, and for how long?

Payloads are stored in the region you choose when you create a workspace and are deleted when your log retention ends: 7, 30 or 90 days depending on plan. We never move data between regions.

We already have an in-house system. How do we migrate?

Most teams dual-send for a week: keep the old worker running, send the same events through Harbor Hooks with delivery paused, compare the logs, then flip endpoints over one customer at a time. Our team will review your plan for free.

What happens if I go over my plan?

We never drop or throttle events because of billing. On Hobby we email you at 80% and 100% and ask you to upgrade; on Scale additional events are billed at $20 per million at the end of the month.

What does the SLA cover?

The 99.99% SLA covers the send API accepting events and our workers attempting delivery. If we miss it in a calendar month, you get service credits of 10 to 50% of that month's bill, applied automatically.

Can I cancel at any time?

Yes. Downgrade to Hobby or close the workspace from settings. Paid plans are billed monthly with no annual commitment, and you can export your delivery log as JSON before you go.

Send your first signed event in five minutes

Free up to 50,000 events a month. No credit card, no sales call.

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Retries and replays never count toward your bill