NewHow the Agent Session Protocol builds trust between autonomous systems.
Product

Every message arrives

Retries, circuit breakers, dead letter queue, and cryptographic proof on every delivery.

You sent a webhook.

It failed.

You retried.

It failed again.

The endpoint came back an hour later.

Your retry budget was gone.

The event was lost.

Your customer never knew.

You never knew either.

Delivery should just work.

Now it does.

Automatic retry engine

Every event follows a precise path. Signature, delivery, retries, circuit breaker, and dead letter queue. No event disappears.

Per endpoint circuit breaker

Endpoints go down. The circuit breaker protects your system by pausing deliveries, probing periodically, and resuming automatically.

Monitor

Every delivery is tracked. Consecutive failures are counted in real time.

Trip

After five consecutive failures, the circuit breaker opens. Deliveries pause.

Probe

npayload sends periodic probes to detect when the endpoint recovers.

Resume

The endpoint responds. The circuit breaker closes. Pending deliveries resume in order.

Failed events are never lost.

Every event that fails after all retries lands in the dead letter queue. Inspect the failure reason, retry count, and timestamp. Replay individually or in bulk. No event disappears. No data is lost.

Dead Letter Queue
1
order.completed
Timeout after 30s
6x
failed
14:22:08
2
payment.refunded
HTTP 503 Service Unavailable
6x
failed
14:23:41
3
user.verified
Connection refused
4x
replayed
14:25:12
4
subscription.cancelled
TLS handshake failed
6x
failed
14:27:55
Inspect. Replay. Never lose an event.

Cryptographic proof on every delivery

Every delivered event carries an HMAC SHA 256 signature. Your endpoint verifies authenticity and integrity without trusting the network.

Step 1

Sign

npayload generates a unique HMAC SHA 256 signature for every delivery.

Step 2

Deliver

The event and signature are sent together to your endpoint.

Step 3

Verify

Your endpoint recomputes the signature and confirms authenticity and integrity.

Before and after npayload Delivery

Without npayload Delivery

  • Custom retry logic in every service
  • No visibility into failures
  • Manual DLQ management
  • No delivery proof
  • Circuit breakers built from scratch
  • Lost events discovered by customers

With npayload Delivery

  • Automatic retries with configurable backoff
  • Real time delivery dashboard
  • Inspect and replay with one click
  • HMAC signature on every delivery
  • Built in circuit breaker per endpoint
  • Dead letter queue catches everything

npayload vs. building it yourself

FeaturenpayloadBuild it yourself
Configurable exponential backoffWeeks of work
Per endpoint circuit breakerComplex to build
DLQ with inspect and replayWeeks of work
HMAC signature verificationDays of work
Real time delivery dashboard
Independent per endpoint trackingMonths of work
Delivery proof with timestamps
Cross org delivery with consent
Three privacy modes

Frequently asked questions

How many retries does npayload attempt?+
Six by default with exponential backoff. Fully configurable per subscription.
What triggers the circuit breaker?+
Five consecutive failures. npayload pauses delivery, probes periodically, and resumes when the endpoint recovers.
Can I replay events from the dead letter queue?+
Yes. Inspect, replay individually, or bulk replay. Events stay until you explicitly remove them.
How does signature verification work?+
HMAC SHA 256 signature on every delivery. Your endpoint recomputes and compares to verify authenticity.
What if our endpoint is down for several hours?+
The circuit breaker protects your endpoint. When it recovers, pending events are delivered in order. Exhausted retries land in the DLQ for replay.
Can we receive the same event at multiple endpoints?+
Yes. Each endpoint has its own retry policy, circuit breaker, and tracking. Failures at one have zero impact on others.
How do we avoid processing the same event twice?+
Every event includes a unique delivery token for idempotent processing.
Do you support delivery to internal systems that are not publicly accessible?+
Yes. npayload delivers through Cloudflare Tunnels. No public IP addresses or inbound firewall rules required.