Polling vs Webhooks: When to Use One Over the Other

January 16, 2026

Keeping customer data in sync across systems is one of the hardest parts of building SaaS products. Most teams eventually face the same architectural question:

Should we poll APIs for changes, or rely on webhooks?

There's no single right answer. Polling and webhooks each come with tradeoffs around freshness, cost, reliability, and operational complexity. And in practice, most real-world integrations end up using some combination of both.

This post breaks down:

• what polling and webhooks actually do at a systems level
• where each approach works well (and where it breaks down)
• how virtual webhooks fit in when native webhooks aren't available

The goal isn't to crown a winner. It's to help you choose the right model for the problem you're solving.

What is polling?

Polling is a client-driven model. Your application periodically calls a third-party API to check whether anything has changed since the last time you looked.

A common polling loop looks like this:

1. Call a list endpoint (e.g. updated_since=timestamp)
2. Process any returned records
3. Store the new checkpoint
4. Sleep until the next interval
5. Repeat

Where polling works well

Polling is often the first integration approach teams reach for because it's simple and widely supported.

Advantages

• Universally available
  If an API exists, polling usually works. No special provider support required.
• Deterministic control
  You choose the schedule. Every 1 minute, every hour, once a day — it's entirely up to you.
• Predictable execution
  You control retries, backoff, and error handling inside your own system.

Where polling breaks down

Polling starts to show its limits as systems scale.

Drawbacks

• Stale data
  Even aggressive polling introduces delay. Your data is only as fresh as your interval.
• Wasted API calls
  Most polls return 'no changes,' but they still consume rate limits and count toward usage.
• Operational overhead
  You end up building and maintaining:
  • schedulers
  • checkpoint tracking
  • pagination logic
  • deduplication
  • backoff and retry behavior
• Rate-limit pressure
  Polling across many customers and objects multiplies API usage quickly.

Polling is best suited for low-urgency, high-volume, batch-oriented workflows where freshness isn't critical.

What is a webhook?

Webhooks invert the control model. Instead of your application asking for updates, the source system pushes events to you when something changes.

When a relevant event occurs, the provider sends an HTTP request to your webhook endpoint containing the updated data.

Where webhooks shine

Advantages

• Fresh data
  Changes are delivered as they happen (or shortly after).
• Lower API usage
  No need to poll continuously for changes that don't exist.
• Event-driven architecture
  Webhooks integrate naturally with automation, workflows, and real-time features.

The real-world challenges of webhooks

Despite their appeal, webhooks aren't a silver bullet.

Limitations

• Not consistently supported
  Many SaaS APIs either don't support webhooks at all or only support them for a subset of objects.
• Provider-dependent behavior
  Event coverage, retries, ordering, and payload structure vary widely by vendor.
• Delivery complexity
  Consumers must handle:
  • retries
  • duplicate events
  • out-of-order delivery
  • transient failures
• Uneven reliability
  Some providers retry aggressively. Others don't retry at all.

Because of this variability, teams often end up with a hybrid integration layer: webhooks for some providers, polling for others.

Native webhooks vs virtual webhooks

At a high level, there are two distinct webhook models:

Native webhooks

Native webhooks are implemented and emitted by the third-party provider itself.

In this model:

• the provider decides when events are emitted
• retry behavior is provider-specific
• Unified acts as a pass-through and does not persist event payloads

Implication

• Delivery and retry semantics are provider-defined
• If the provider does not retry (or retries briefly), missed events may be lost
• Consumers should treat delivery as best-effort

Virtual webhooks

Virtual webhooks simulate webhook behavior for APIs that don't support native webhooks.

Under the hood:

• Unified polls the source API on a configured interval
• Detects created or updated records
• Emits webhook events when changes are found
• Handles pagination, retries, and backoff internally

From the consumer's perspective:

• Events arrive via a webhook endpoint
• No polling logic is required in your application

Key architectural difference

Unified controls the polling, change detection, and dispatch pipeline for virtual webhooks. That allows Unified to provide deterministic, change-based delivery.

Delivery semantics (important distinction)

Delivery behavior differs by webhook type, and it's important to be explicit about this.

Virtual webhooks

For virtual webhooks, Unified controls:

• when data is read
• how changes are detected
• when events are emitted

As a result:

• Events are emitted once per detected change
• Retries are handled internally before dispatch
• Consumers receive deterministic change notifications

In practice, this behaves like exactly-once emission per detected change, although consumers should still design idempotent handlers to account for network-level retries.

Native webhooks

For native webhooks:

• Unified does not persist payloads
• Delivery depends entirely on the upstream provider
• Retry behavior and guarantees vary by vendor

Consumers should assume:

• possible duplicate deliveries
• potential out-of-order arrival
• no guarantee of replay if delivery fails

Initial sync and ongoing updates

When creating a webhook, Unified supports an optional initial backfill.

Initial sync behavior

By creating a webhook with:

include_all=true

Unified will:

1. Fetch all existing records for the subscribed object
2. Deliver data in paged webhook payloads
3. Respect the provider's maximum page size (page_max_limit)
4. Emit a final payload with type = INITIAL-COMPLETE when backfill finishes

Your webhook endpoint may be called multiple times during this initial sync.

After completion:

• the webhook transitions to normal operation
• only new or updated records generate events

Ongoing delivery

For both native and virtual webhooks:

• payloads may be batched (up to provider limits)
• multiple POSTs can occur for a single run if many records change

Billing and cost considerations

Polling and webhooks also differ in how usage accumulates.

Polling

• Every poll counts as an API request
• Empty polls still consume usage
• Pagination multiplies request volume

Native webhooks

• Billable when events are successfully dispatched
• Behavior depends on provider emission patterns

Virtual webhooks

• Billable only when new data is discovered and dispatched
• Empty polling intervals are not billed
• Failed reads or failed dispatches are not billed

This model makes virtual webhooks more predictable at scale, especially for low-change datasets.

Handling duplicates and idempotency

Unified explicitly documents that:

• duplicate events can occur
• events may arrive out of order

Recommended handling pattern:

• always update records based on the latest updated_at
• perform atomic writes
• skip updates when incoming data is older than stored state

This approach protects against:

• duplicate deliveries
• rapid successive updates
• transient network issues

When to use each approach

Use polling when

• freshness isn't critical
• datasets are very large and change frequently
• provider webhook support is inconsistent
• batch reconciliation is acceptable

Use native webhooks when

• the provider offers reliable webhook support
• near real-time updates are required
• event volume is manageable

Use virtual webhooks when

• APIs don't support native webhooks
• you want event-driven behavior without polling logic
• predictable cost and consistent schemas matter
• you want Unified to handle retries, pagination, and backoff

Final takeaway

Polling and webhooks are tools, not ideologies.

Polling offers control and universality at the cost of freshness and efficiency. Webhooks offer real-time behavior but introduce variability and reliability concerns. Virtual webhooks bridge the gap by combining deterministic polling with webhook-style delivery.

Understanding the tradeoffs — especially around delivery semantics, retries, and cost — lets you choose the right model for each integration instead of forcing everything into one pattern.

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