Webhooks vs Polling
Webhooks are event-driven push — the provider calls you when something happens. Polling is scheduled pull — you call the provider to ask what happened. The difference in efficiency, complexity, and reliability shapes which you should choose.
TL;DR
- Webhooks: provider sends an HTTP POST to your URL when an event occurs. Real-time, efficient, but requires a public endpoint and robust failure handling.
- Polling: your code calls the provider's API on a schedule to check for new data. Simple, resilient, but generates empty requests and adds latency.
- Always acknowledge webhooks with 200 immediately — process asynchronously. Never do heavy work synchronously in the webhook handler.
- Best pattern: webhooks for real-time + periodic reconciliation poll as a safety net for missed events.
At a Glance
| Attribute | Webhooks | Polling |
|---|---|---|
| Pattern | Push — provider calls you | Pull — you call the provider |
| Latency | Near real-time (seconds) | Up to polling interval (minutes) |
| Efficiency | High — requests only on events | Low — many empty requests |
| Implementation | Register URL + handle incoming POST | Cron job calling API endpoint |
| Requires public URL | Yes — provider must reach your server | No — you initiate all connections |
| Failure handling | Provider retries; you must deduplicate | Simple — retry on next poll cycle |
| Event ordering | Not guaranteed (parallel deliveries) | Chronological if sorted by timestamp |
| Works behind firewall | No (unless tunneled) | Yes — outbound calls only |
| Local development | Requires ngrok or CLI tunnel | Works natively (localhost can poll) |
| Event deduplication | Required (provider retries) | Optional (idempotent reads usually fine) |
| Best for | Payment events, CI triggers, real-time sync | Batch sync, firewall-restricted envs, simple integrations |
Quick Decision
Use Webhooks when…
- You need near real-time event notification (payments, order updates)
- Events are infrequent — polling would generate mostly empty requests
- The provider supports webhooks (Stripe, GitHub, Shopify, Twilio all do)
- Your server is publicly accessible or you can configure a tunnel
- You want to trigger immediate actions (send email on payment, deploy on push)
- You're building an integration that processes high event volumes efficiently
Use Polling when…
- The provider doesn't offer webhooks (legacy APIs, older SaaS tools)
- Your server is behind a firewall or VPN and can't receive inbound connections
- You need guaranteed event ordering and deduplication-free simplicity
- Local development without webhook tunnelling setup
- Batch sync is acceptable (syncing data every 5–15 minutes)
- You want simple failure recovery — next poll picks up where you left off
Deep Dive
Webhooks — Event-Driven Push
A webhook is an HTTP POST request sent by the provider to a URL you register, triggered by an event (payment.succeeded, push, order.created). Your server receives the payload, validates the signature (HMAC-SHA256 with your webhook secret), and processes the event. The cardinal rule: respond with 200 immediately, then process asynchronously via a job queue. If you spend 30 seconds processing synchronously, the provider may time out and retry — causing duplicate processing.
Webhooks must be idempotent because providers retry on failure. Store the event ID and skip if already processed. Use a unique constraint on the event ID in your database as the deduplication mechanism. For very high volumes, use an inbound queue (SQS, Redis Streams) between your webhook endpoint and processors — the endpoint's only job is to enqueue and respond 200.
Security: always verify the HMAC signature before processing. Without verification, your webhook endpoint can be called by anyone sending a POST request — a potential attack vector for injecting fake events (fake payment.succeeded to unlock features without paying).
Polling — Scheduled Pull
Polling is the "ask, don't listen" pattern. A cron job (every 1 minute, every 5 minutes, hourly) calls the provider API, fetches recent events or updated records, compares against local state, and processes any deltas. Simple to implement, requires no inbound connectivity, and naturally handles provider downtime: the next poll cycle picks up where the last succeeded.
The efficiency cost: polling generates requests proportional to time, not events. At 1-minute polling with 10 events/day, you make 1,440 requests to receive 10 events — a 144× overhead. API rate limits compound this: providers impose per-minute or per-day call limits. High-frequency polling on large systems burns through rate limits, causing throttling that reduces effective data freshness below the polling interval.
Long polling reduces empty requests by keeping the connection open until an event arrives (or timeout). It's a midpoint between polling and webhooks — requires only outbound connections but approaches webhook latency. Used by Slack's Events API (before they added webhooks), Slack's RTM API, and many chat systems.
Real-World Patterns
Payment Processing (Webhooks)
Stripe is the canonical webhook use case. When a customer's payment succeeds, Stripe sends payment_intent.succeeded to your webhook endpoint within seconds. Your handler: (1) verify Stripe-Signature header, (2) enqueue job, (3) return 200. The job: check if event ID already processed, if not — provision access, send confirmation email, update order status. Without webhooks, polling for payment status would require frequent API calls and add minutes of delay to order fulfilment. Stripe sends 150+ event types — subscribe only to the events you need to avoid processing overhead.
CI/CD Pipeline (Webhooks)
GitHub Actions, CircleCI, and Jenkins are triggered by GitHub push webhooks (push, pull_request, release events). When you push a commit, GitHub sends a webhook to your CI server within seconds — the build starts immediately. The alternative (polling GitHub's API for new commits every minute) would add up to 60 seconds of latency to every build trigger and consume GitHub API rate limits. For a team pushing 50 times/day at 60s polling intervals, webhook latency is effectively zero vs up to 1 minute for polling — a meaningful developer experience difference.
Legacy API Integration (Polling)
A company integrates with an ERP system that was built in 2008 and has no webhook support — only a REST API for querying records. Their integration polls the ERP's /orders endpoint every 5 minutes, filtering by updated_at > last_sync_time. On each poll, they process new or updated orders, update their local database, and advance the sync cursor. This pattern is less efficient but the only option when the provider doesn't support webhooks. To reduce empty polls, they use the ERP's If-Modified-Since HTTP header — the server returns 304 Not Modified if nothing changed, reducing payload transfer cost.
The Dual Pattern — Webhooks + Reconciliation Poll
The most resilient production architecture: webhooks for real-time event processing + a periodic reconciliation poll as a safety net. Webhooks handle 99.9% of events in real time. A daily or hourly reconciliation job polls the provider's API for all events in the last 24 hours and cross-references with locally processed event IDs — catching any webhook deliveries that failed all retries. Used by Stripe's own integration guide, GitHub's recommendations, and enterprise middleware platforms like MuleSoft. The poll is a cheap safety net; the webhook is the fast path.
Verdict: Webhooks for Efficiency, Polling for Simplicity — Use Both for Resilience
If the provider supports webhooks and you have a publicly reachable server, webhooks are almost always the correct choice — they're efficient, real-time, and align with event-driven architecture principles. The implementation cost of proper webhook handling (signature verification, async processing, deduplication) is a one-time investment that pays off in operational efficiency and responsiveness.
Use polling when webhooks aren't available, when you're behind a firewall, or during development. Add a periodic reconciliation poll even when using webhooks in production — it's cheap insurance against missed events and makes your system resilient to provider-side webhook delivery failures.
Decision Checklist
| Scenario | Choose |
|---|---|
| Real-time payment event handling | Webhook |
| Provider has no webhook support | Polling |
| Server behind corporate firewall/VPN | Polling |
| CI/CD pipeline triggered by code push | Webhook |
| Hourly batch sync of CRM records | Polling |
| Stock price or market data feed | WebSocket (or polling) |
| Local development / testing integrations | Polling (or ngrok) |
| Order fulfilment triggered by payment | Webhook |
| Syncing inventory from legacy ERP | Polling |
| Guaranteed no missed events | Webhooks + reconciliation poll |
| Simple integration with minimal infrastructure | Polling |
| High event volume (10K+ events/day) | Webhook |
Frequently Asked Questions
What happens if a webhook delivery fails?
Most webhook providers implement retry logic: if your endpoint returns a non-2xx status or times out, they retry the delivery after an exponential backoff (e.g., 5s, 30s, 5min, 30min, 2hr). Retry policies vary by provider — Stripe retries up to 3 days; GitHub retries up to 3 times over 72 hours; Shopify retries 19 times over 48 hours. If all retries fail, the event is dropped. To protect against missed events: (1) acknowledge webhooks immediately with a 200 response, process asynchronously; (2) poll your provider's API periodically to reconcile events against your local state; (3) use the provider's event log/audit API for recovery.
How do I verify a webhook is from a legitimate sender?
Webhook payload verification uses HMAC signatures. The provider includes a signature in a header (e.g., Stripe-Signature, X-Hub-Signature-256) computed as HMAC-SHA256 of the raw request body using a shared secret. Your server recomputes the signature with your webhook secret and compares using a constant-time comparison function (to prevent timing attacks). Never compare signatures with ===; use crypto.timingSafeEqual() in Node.js or hmac.compare_digest() in Python. Always verify signatures before processing any webhook — an unverified endpoint is a potential SSRF or injection attack surface.
Is polling always inefficient?
No — polling efficiency depends on interval and event frequency. If events occur every 30 seconds and you poll every 30 seconds, the overhead is one API request per event — equivalent to webhook delivery. Polling becomes inefficient when events are rare and polling is frequent: polling every second for an event that fires once per hour generates 3,600 empty requests per event. Long polling improves this dramatically: the server holds the connection open until an event occurs (or a timeout), reducing empty responses. For most practical cases, polling intervals of 1–5 minutes are efficient enough for non-real-time use cases.
Can I use webhooks in a local development environment?
Webhooks require a publicly accessible URL — your localhost:3000 is not reachable by Stripe or GitHub. Tools for local webhook development: (1) ngrok — tunnels a public URL to your local port; simple and widely used. (2) Stripe CLI (stripe listen --forward-to localhost:3000) — official Stripe tool for forwarding webhooks locally with event simulation. (3) Cloudflare Tunnel, LocalTunnel, serveo.net — alternatives to ngrok. (4) Provider-specific CLIs (GitHub Codespaces, Vercel dev tunnel). For CI/CD pipelines, many providers offer webhook simulation or test mode without requiring a live endpoint.
What is long polling and how does it differ from regular polling?
Regular polling: client sends a request → server immediately responds with current data (or empty if no update) → client waits interval → repeat. Long polling: client sends a request → server holds the connection open until new data is available (or a timeout, typically 30–60 seconds) → server responds → client immediately makes a new request. Long polling dramatically reduces empty responses and approaches real-time latency. It was the standard real-time technique before WebSockets. Downsides: servers must handle many concurrent held connections; HTTP/1.1 connection limits per domain (6 connections in browsers) can block other requests.
What are WebSockets and when should I use them instead of webhooks?
WebSockets provide a persistent bidirectional connection between client and server, enabling real-time data flow in both directions. Webhooks are server-to-server (provider pushes to your server). WebSockets are server-to-browser or app (your server pushes to a connected client). Use cases: WebSockets for live chat, multiplayer games, real-time collaboration (Google Docs), live dashboards, stock tickers. Webhooks for payment notifications, CI/CD triggers, cross-service event notifications, e-commerce order updates. The difference: WebSockets require a persistent connection (stateful), webhooks are stateless HTTP POST requests to a URL.
How do webhooks handle high event volume?
For high-volume webhooks, your endpoint must: (1) respond immediately with 200 — process events asynchronously using a job queue (Redis + BullMQ, SQS, RabbitMQ). (2) Handle idempotently — providers may deliver the same event multiple times on retry. Use the event ID to deduplicate: store processed event IDs and skip if already handled. (3) Scale horizontally — webhook handlers are stateless HTTP endpoints and scale easily behind a load balancer. (4) Implement backpressure — if a provider allows event batching, use it. Stripe sends one event per delivery; GitHub's webhook batching depends on configuration.
Is there a middle ground between webhooks and polling?
Yes — several patterns fill the gap: (1) Server-Sent Events (SSE): server streams events over a persistent HTTP connection (unidirectional — server to browser). Simpler than WebSockets, works over HTTP/2 with automatic reconnect. (2) GraphQL Subscriptions: real-time updates to specific queries using WebSockets under the hood. (3) Long polling with conditional GET (ETags/Last-Modified): server returns 304 Not Modified if content unchanged, reducing payload on empty polls. (4) Change Data Capture (CDC): database-level event streaming (Debezium, AWS DMS) for internal event propagation across services. Choose based on your infrastructure control, client type, and event latency requirements.
Related Comparisons
Verdict: Choose Based On Your Situation
Webhooks
- You want instant event notifications
- You need real-time responsiveness
- You have reliable infrastructure
- You want efficient resource usage
Polling
- You want simplicity and reliability
- You have intermittent data changes
- You're okay with slight delays
- You want easier error handling