Which Event Delivery Model Scales: Polling, Webhooks, or Virtual Webhooks?

January 22, 2026

As products grow, the way they detect and react to data changes becomes infrastructure, not implementation detail.

Most teams start with one of three event delivery models:

• polling,
• native webhooks, or
• virtual webhooks.

All three work at small scale. Only some continue to work as usage, customers, and integrations grow.

This post explains what actually scales, and why.

Polling: simple to start, hard to grow

Polling means your application periodically asks an API whether anything changed.

Typical pattern:

• Run a job every N minutes
• Request records updated since the last check
• Diff, dedupe, retry, repeat

Why polling struggles at scale

Polling breaks down not because it's inefficient, but because it's fragile.

Rate limits

• Most polls return no new data
• API quota is burned regardless
• High-volume tenants punish low-volume ones

Missed updates

• Clock drift, retries, or overlapping windows cause gaps
• Incremental filters are inconsistently implemented across APIs
• Partial failures are easy to miss and hard to detect

Duplicate events

• Same record appears across multiple polling windows
• Requires idempotency logic everywhere
• Ordering guarantees are rare

Operational overhead

• Schedulers
• Backoff logic
• Error recovery
• State tracking per integration

Polling works when data is not time-sensitive and volume is small. It does not scale cleanly across many tenants, many integrations, or real-time use cases.

Native webhooks: ideal, but limited

Native webhooks invert the model:

• The source system detects a change
• It pushes an event immediately
• Your app reacts

This is the cleanest architecture.

Where native webhooks fall short

Coverage

• Many APIs don't offer webhooks at all
• Others support only a subset of objects or events

Inconsistency

• Payload formats vary wildly
• Event semantics differ (created vs updated vs partial change)
• Ordering and deduplication are rarely guaranteed

Partial delivery

• Some providers send IDs only
• Others send incomplete payloads
• Follow-up fetches are often required

Native webhooks scale well when they exist. The problem is that most SaaS APIs don't provide them consistently enough to rely on as a universal solution.

Virtual webhooks: designed for scale

Virtual webhooks are an architectural response to the gaps left by polling and native webhooks.

Instead of relying on the source to push events, the platform:

1. Polls the source API on a controlled interval
2. Detects changes reliably
3. Emits webhook events when changes are found

From the application's perspective:

• You subscribe once
• You receive events
• You don't manage polling infrastructure

Why virtual webhooks scale better

Controlled load

• Polling frequency is centralized and tuned
• Idle accounts don't waste API calls
• Rate limits are handled once, not per customer

Consistent delivery

• Events follow a single schema
• Change detection logic is standardized
• Deduplication and retries are centralized

Fewer failure modes

• No per-integration cron jobs
• No distributed polling state
• No silent gaps when jobs fail

Predictable freshness

• Latency is primarily bounded by polling interval, rather than batch sync cadence
• No dependency on batch completion

Virtual webhooks are not about eliminating polling. They are about containing it, so it doesn't leak into every product surface.

Event delivery comparison

When each model makes sense

Polling

• Backfills
• Non-time-sensitive reporting
• Low-volume internal tools

Native webhooks

• Payments
• Infrastructure events
• APIs with strong webhook guarantees

Virtual webhooks

• Multi-tenant SaaS
• Cross-vendor integrations
• AI-native apps, agents and automation
• User-facing real-time features

The takeaway

Polling works early. Native webhooks work when they exist. Virtual webhooks are designed to scale when neither assumption holds.

Choosing an event delivery model isn't about preference—it's about which failure modes you're willing to own as your product grows.

Learn more about Unified's approach to virtual webhooks and real-time event delivery:

• Unlock real-time data with virtual webhooks
• Replacing Polling with Unified Webhooks and Virtual Streams

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