Build vs Buy: Should You Build Webhook Infrastructure In-House?

Every growing SaaS company faces the same question: build webhook infrastructure ourselves or use a managed service?

Webhooks seem simple—they're just HTTP POSTs. But as GitHub, Segment, and Square discovered, webhook delivery is a distributed systems problem. GitHub's 2018 outage permanently lost 200,000 payloads. Segment spent 9 months building Centrifuge after discovering traditional queues couldn't handle their scale.

This post breaks down what building entails, realistic costs and timelines, and whether building or buying makes sense.

What Building Webhook Infrastructure Actually Involves

Production-ready webhook delivery requires solving multiple interconnected problems.

Retry Logic and Backoff Strategies

Webhooks fail constantly: endpoints down, network timeouts, rate limits. Production systems need intelligent exponential backoff and jitter to avoid thundering herds.

Segment discovered: 1.5% of data succeeds on retry, 50% between 3rd-10th attempts. Retry strategy needs hours or days, not minutes. Stripe: 3 days. Square: 72 hours. PayPal: 25 attempts over 3 days.

Requires: retry queues, configurable backoff, attempt limits, dead-letter queues.

Circuit Breakers for Failing Endpoints

Dead endpoints cause endless retries, clogging queues and delaying other deliveries. Convoy's circuit breaker reduced failed attempts from 100K/day to 5K (95% improvement). Building a distributed circuit breaker requires shared state (Redis), leader election, and configured thresholds.

Signature Verification and Security

Every webhook must be cryptographically signed for authenticity. Svix cataloged 9 common failure modes: weak primitives, shared secrets, no replay protection, no zero-downtime rotation.

Proper implementation requires: HMAC-SHA256 with per-endpoint secrets (24+ bytes), signed timestamps, message IDs, secret prefixes, and multi-signature rotation support.

Customer-Facing Portal

Customers need: endpoint management (add/update/disable/delete), delivery logs with full request/response visibility, filtering by event type and status, manual replay, and health indicators.

Monitoring and Observability

Requires: queue depth, event age, latency at p95, success rates by endpoint, dead-letter queue alerts. Also need customer-facing analytics: success rates, latency, volume trends.

Scaling Challenges

Problems compound at scale: slow endpoints create backpressure, large customer batches block small ones, outages spike traffic 10-100x, misbehaving endpoints break pipelines.

Segment discovered every conventional queue fails at scale in unique ways. Solution: use relational database as "virtual queue" instead of message broker. They reached 2M HTTP requests/second after extensive iteration.

Realistic Engineering Costs and Timeline

Timeline: 3-6 months for initial release (assumes distributed systems experience)

Month 1: architecture and basic delivery. Months 2-3: retries, circuit breakers, dead-letter queues. Months 4-6: portal, monitoring, hardening.

Ongoing maintenance: 0.5-1 FTE not a "build once and forget" system

Hidden costs:

• Infrastructure (queues, databases, workers, monitoring)
• On-call burden
• Opportunity cost vs core product
• Security audits for crypto
• Documentation and SDKs

One engineering manager at Guesty called it "a nightmare" and "personal source of pain." Common sentiment among teams that underestimated complexity.

Build vs Buy: Comparison Table

When Building In-House Makes Sense

Very custom requirements - unique constraints no provider supports (specialized compliance, proprietary integrations)

Webhooks are your core product - you need in-house expertise for competitive advantage

Large, experienced distributed systems team - 50+ engineers with platform groups can absorb this

Massive scale - at Segment-level scale (hundreds of thousands events/second), provider costs become prohibitive

High-volume long-term commitment - confident processing billions/month for years

When Buying Makes Sense

Time to market matters - customers asking for webhooks today; 3-6 months building = lost opportunity

Small team - teams under 20 people can't build and maintain without sacrificing product. True cost often exceeds estimates by 3-5x.

Not your differentiator - webhook delivery is table stakes, not competitive advantage. Customers care it works, not how.

Focus on core product - every hour on retries is an hour not on differentiating features

Need proven reliability - managed services already solved edge cases and outages

Making the Decision for Your Team

1. How many months of engineering time can we allocate to webhook infrastructure?
2. Do we have distributed systems expertise in-house?
3. Is webhook delivery a competitive differentiator?
4. What's the cost of delayed time to market?
5. Who's on-call when the system breaks at 3 AM?

For most teams, answers point toward buying. 3-6 months of engineering typically costs $150K-300K alone. Managed service costs a fraction and works immediately. Use webhook provider checklist to compare options systematically.

How Hook Mesh Fits

Hook Mesh handles retries, circuit breakers, signature verification, and scaling. Free tier for getting started, scales predictably for SMB budgets. Battle-tested infrastructure, SDKs in major languages, embeddable portal, full visibility.

The question isn't whether you can build—it's whether you should, given everything else competing for your engineering time.

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Ready to add webhooks to your product without the infrastructure headache? Start free with Hook Mesh and send your first webhook in minutes.