Why Your Platform Needs Outbound Webhooks

Every API-driven platform eventually faces the same inflection point. Customers stop asking "can I pull data from your API?" and start asking "can you push events to me when something happens?" That shift, from polling to real-time, from request-response to event-driven, is the moment webhooks move from nice-to-have to table stakes.

But knowing you need webhooks and knowing how to deliver them reliably at scale are two very different problems. This guide breaks down why outbound webhooks matter, what it actually takes to build them properly, and how to make the right build-versus-buy decision for your team.

Why Teams Add Outbound Webhooks

The request rarely arrives as a clean feature spec. It shows up as a pattern: a customer builds a brittle polling loop against your API, a sales prospect asks about "real-time notifications" during a demo, or your support queue fills with tickets from users who missed a critical state change because they didn't check in time.

Here are the most common drivers that push a webhook feature up the roadmap.

Customers Need Real-Time Awareness

Polling is wasteful and slow. A fintech platform processing payments can't expect its customers to hit a GET endpoint every few seconds hoping to catch a settlement confirmation. A logistics provider can't ask partners to continuously check for shipment status updates. When your platform holds time-sensitive state (transactions, deployments, deliveries, model completions) your customers need to know the moment something changes. Webhooks solve this by inverting the communication model: your platform pushes the event, and the customer's system reacts immediately.

Reducing API Load and Infrastructure Cost

Polling is expensive for both sides. Every unanswered "has anything changed?" request burns compute, bandwidth, and rate-limit budget. Platforms that serve thousands of integrators often find that polling traffic dwarfs legitimate read/write operations. Webhooks eliminate this waste. Events flow only when something meaningful happens, which means lower API traffic, reduced infrastructure costs, and more headroom for the requests that actually matter.

Enabling an Integration Ecosystem

Webhooks are the simplest building block for third-party integrations. They require no proprietary SDK, no persistent connection, and no special protocol, just standard HTTP. That low barrier makes it easy for customers, partners, and no-code platforms like Zapier or Make to build workflows on top of your product. Every webhook endpoint your platform supports becomes a potential integration point, and each new integration increases the switching cost for customers who've woven your events into their operations.

Revenue and Retention Opportunities

Once customers depend on your webhooks to trigger their own business logic (syncing a CRM when an order closes, alerting a fraud system when a charge is flagged, kicking off a CI pipeline when a deploy completes) your product becomes embedded in their infrastructure. That stickiness translates directly to lower churn. It also opens monetization paths: tiered endpoint limits, premium event types, or higher delivery guarantees packaged into enterprise plans.

Competitive Expectation

For many product categories, webhooks are no longer a differentiator, they're a baseline requirement. Developer-facing platforms in payments, communications, DevOps, and AI/ML are expected to offer webhook support. Not having them is increasingly a reason prospects walk away during evaluation.

What a Reliable Webhook System Actually Requires

Here's where the gap between "we should add webhooks" and "we shipped a production-grade webhook system" gets wide. A naive implementation (fire-and-forget HTTP POST on every event) works fine in a demo but fails in production due to lack of reliability, observability, and security.

Guaranteed Delivery and Retry Logic

Networks fail. Customer endpoints go down. A responsible webhook system must guarantee at-least-once delivery, which means persisting every event before attempting delivery and retrying on failure. Retry strategies need exponential backoff with jitter to avoid thundering-herd scenarios when a downstream service recovers from an outage. You need dead-letter handling for events that permanently fail, and circuit breakers to stop hammering endpoints that are clearly unhealthy. Getting this right means managing durable queues, tracking delivery state per event per subscriber, and handling edge cases like partial failures across a fanout.

Idempotency and Deduplication

At-least-once delivery means duplicates are inevitable. Every event needs a stable, unique identifier so that consumers can safely deduplicate on their end. Your system should include idempotency headers and clear documentation so customers know how to handle repeated deliveries without double-processing a payment or shipping an order twice.

Security From Day One

Webhook payloads travel over the public internet to endpoints you don't control. That means every delivery must be signed so recipients can verify authenticity, typically using HMAC-SHA256 with a per-subscriber secret. Timestamps should accompany signatures to prevent replay attacks. Secrets need to be rotatable without downtime. And your system needs to guard against SSRF vulnerabilities to make sure internal services can't be reached through maliciously crafted callback URLs.

Multi-Tenancy and Isolation

In a SaaS platform, one customer's infrastructure problems shouldn't affect anyone else's webhook delivery. A slow or failing endpoint for Tenant A must not create backpressure that delays events for Tenant B. Achieving this requires per-tenant queuing, independent retry tracking, and careful resource isolation, all of which add architectural complexity.

Observability and Self-Service Debugging

When a webhook delivery fails, customers need visibility. That means a portal or API where they can inspect delivery attempts, see response codes and latency, and manually retry failed events. Internally, your team needs dashboards tracking delivery success rates, p95/p99 latency, queue depth, and error classification. Without observability, every delivery issue becomes a support ticket.

Subscription Management and Filtering

Customers need to choose which events they care about and where those events go. A mature webhook system supports topic-based subscriptions (e.g., "send me payment.completed and refund.issued but not invoice.created"), multiple endpoints per subscriber, and API-driven management of subscriptions. Some customers want a single firehose; others want surgical precision.

Build In-House or Adopt an Existing Solution?

This is the fork in the road where most engineering leaders spend the most time deliberating, and where the true cost of each path is easiest to underestimate.

The Case for Building

There are legitimate reasons to build your own webhook delivery infrastructure. If your platform has unusual delivery semantics, such as ordering guarantees that go beyond standard at-least-once, payload transformations that are deeply coupled to your domain model, or compliance requirements that prohibit third-party data handling, then a custom system gives you full control.

Building also makes sense if you already operate a mature event-driven architecture with the necessary primitives (durable queues, delivery tracking, observability) in place, and adding outbound webhooks is a relatively thin layer on top.

Where it gets expensive. In practice, most teams underestimate the scope. What starts as "just POST to a URL on every event" grows to include retry management, secret rotation, rate limiting, per-tenant isolation, a customer-facing delivery log, and on-call support for delivery failures. Based on build-versus-buy analyses across the webhook ecosystem, the initial build typically spans six to twelve months of dedicated engineering time, with ongoing maintenance consuming one to two engineers continuously.

The hidden cost isn't the initial build, it's the opportunity cost. Every sprint your backend team spends on webhook plumbing is a sprint they're not spending on your core product. And the maintenance burden compounds: as your customer base grows, so do the edge cases, the scaling challenges, and the support load.

The Case for an Off-the-Shelf Solution

Managed webhook infrastructure has matured significantly. Modern solutions handle the hard parts (durable delivery, retries with backoff, signing, multi-tenancy, observability, and customer-facing portals) out of the box. Integration typically takes days rather than months.

Where it shines. For most teams, the economics are clear. A managed service eliminates the ongoing maintenance burden, provides battle-tested reliability from day one, and frees engineering capacity for differentiated work. The total cost of ownership over a two-to-five-year horizon is typically a fraction of a custom build when you account for engineering time, infrastructure costs, and opportunity cost.

Where to be cautious. Vendor lock-in is a real concern. If your webhook provider goes down, your customers' integrations break. Pricing models that charge per event can become expensive at high volumes. And some managed services are opaque, you lose visibility into the delivery pipeline and can't customize behavior for edge cases.

The ideal solution would combine the reliability and operational leverage of a managed service with the transparency and flexibility of open-source infrastructure. That's a rare combination, but it's the design behind Hookdeck Outpost.

A Third Option: Hookdeck Outpost

Rather than forcing a binary choice between building everything yourself or depending entirely on a hosted service, Outpost provides open-source webhook infrastructure that you can self-host for full control or run as a managed service for operational simplicity.

What Outpost Is

Outpost is an outbound event delivery system written in Go, licensed under Apache 2.0, that's fully open source. It's built for SaaS and API platforms that need to push events to customer-defined destinations with production-grade reliability. You can integrate it as a sidecar, a standalone microservice, or a shared infrastructure component, and it's designed to scale from a handful of tenants to thousands.

Flexible Destinations — Not Just HTTP Callbacks

One of Outpost's most distinctive capabilities is that it doesn't limit you to HTTP webhook endpoints. Out of the box, it supports delivering events to webhooks, Amazon EventBridge, AWS SQS, Amazon S3, Google Cloud Pub/Sub, RabbitMQ, Azure Service Bus, and Kafka.

This matters because not every customer wants to receive events via HTTP callbacks. Enterprise customers increasingly prefer events delivered directly to their own message brokers or event buses, where they can apply their own processing pipelines, filtering, and retention policies. Outpost lets you offer this flexibility without building separate delivery paths for each destination type.

Production-Grade Delivery Without the DIY Burden

Outpost ships with the features that take months to build from scratch: at-least-once delivery guarantees with configurable retry strategies, HMAC signatures with per-subscriber secrets and rotation support, topic-based publish/subscribe for fine-grained event routing, event fanout to multiple destinations in parallel, a customer-facing portal for self-service destination management and delivery debugging, and OpenTelemetry-native observability with standardized traces, metrics, and logs.

Multi-tenancy (one of the hardest problems to get right in a custom build) is a first-class concept in Outpost. Each tenant gets isolated delivery tracking and independent retry state, so one customer's failing endpoint never creates backpressure for another. You can create and manage tenants programmatically via the API, and each tenant's users get their own portal view to manage destinations and debug delivery issues.

It also follows the Standard Webhooks specification, meaning deliveries use standardized header formats and signing conventions that are compatible with widely-used webhook verification libraries.

Minimal Dependencies, Maximum Flexibility

The runtime footprint is deliberately lean: Redis (or a wire-compatible alternative) for coordination, PostgreSQL for delivery logs, and one of the supported message queues for event transport. Outpost can run as a single process for simpler deployments or as separate API, delivery, and log-processing services when you need to scale each independently.

SDKs are available in Go, Python, and TypeScript, and there's an MCP server for AI-assisted integration workflows.

Self-Hosted or Managed: Your Call

Self-hosted gives you full control over your data, deployment topology, and infrastructure. You run Outpost on your own infrastructure, manage scaling and upgrades on your own terms, and retain complete ownership of the delivery pipeline. This is ideal for teams with strict data residency requirements or those who want to embed webhook delivery deeply into an existing microservices architecture.

Managed Outpost runs on Hookdeck's infrastructure with serverless scaling, SOC 2 compliance, and a customer-facing portal included. It's built on the same open-source codebase that powers self-hosted deployments, so there's no feature gap between the two modes. Pricing starts at $10 per million events, roughly a tenth of the cost of comparable managed webhook services. For teams that want production-grade delivery without the operational overhead, the managed option delivers reliability from day one.

The key point is that neither option is a dead end. You can start self-hosted and migrate to managed (or vice versa) as your needs evolve, because the underlying codebase is identical.

Getting Started

Outpost ships with Docker quickstart guides for both RabbitMQ and AWS SQS (via LocalStack), so you can evaluate it locally before committing to a deployment strategy. The typical integration path looks like this: spin up Outpost alongside your application, create tenants and destinations via the API or SDKs, publish events to topics from your application code, and point your customers at the self-service portal to manage their own destinations.

From there, you're delivering events to wherever your customers need them, with retries, signing, observability, and multi-tenant isolation handled for you.

Making the Decision

The right choice depends on your team's constraints, but a few heuristics help:

Build in-house if webhook delivery is genuinely a core differentiator for your product, you have a dedicated infrastructure team with bandwidth to spare, and your requirements are unusual enough that no off-the-shelf solution fits.

Adopt Outpost self-hosted if you want production-grade webhook infrastructure without vendor lock-in, need to keep event data on your own infrastructure, and have dedicated platform engineering or DevOps capacity to manage containerized infrastructure (Redis, PostgreSQL, and a message queue). You get the reliability of a purpose-built system with the transparency and control of open source.

Adopt Outpost managed if you want to start delivering webhooks in days rather than months, prefer to offload operational concerns like scaling, uptime, and compliance, and want predictable, low-cost pricing that won't blow up as your event volume grows.

In all three scenarios, the goal is the same: give your customers reliable, real-time event delivery so they can build on top of your platform with confidence. The question is just how much of the undifferentiated heavy lifting you want to own.

If you're considering webhook infrastructure for sending webhooks, check out our guide to evaluating outbound webhook infrastructure.