APIs and webhooks both let software systems exchange information, but they initiate communication differently. An API typically responds when another application requests data or asks it to perform an action. A webhook sends a notification automatically when a specified event occurs.
When it comes to webhook vs API, I recommend the following:
- Use an API when your application needs to request data or perform an operation on demand.
- Use a webhook when another system should notify your application that something happened.
- Many business integrations use both, with a webhook starting the workflow and an API retrieving data or completing the next action.
For revenue teams, that combination can support faster lead processing. A form submission can trigger a workflow, while ZoomInfo’s Enrich API adds company and contact information before the lead is scored or routed. This gives the routing process more context than a basic form submission alone.
- Webhook vs API at a glance
- When to use APIs, webhooks, or both
- API vs webhook: 8 key differences
- API vs webhook for automated lead routing
- How ZoomInfo supports an API and webhook lead-routing workflow
- API and webhook security best practices
- How to choose between webhook vs API
- Common API and webhook mistakes
- Frequently asked questions
Webhook vs API at a glance
The main difference between a webhook vs API is request-response versus event-driven communication. APIs wait for a system to make a request. Webhooks are configured to send an HTTP request when a particular event occurs.
| Area | API | Webhook |
|---|---|---|
| Best for | On-demand data and operations | Event-triggered automation |
| Communication model | Request-response | Event-driven |
| Who initiates | Requesting application | Source application |
| Typical timing | On demand | When an event occurs |
| Polling required | Sometimes | No |
| Data flexibility | Broad queries and actions | Usually tied to a defined event |
| Common actions | Retrieve, create, update, or delete data | Notify another system of an event |
| Common example | Look up account details | Notify a CRM when a form is submitted |
When to use APIs, webhooks, or both
When to use an API
An API (application programming interface) defines how one software system can request data or functionality from another. APIs typically use a request-response pattern: an application sends a request to an endpoint, and the other system returns data, performs an action, or reports an error.
Use an API when your application knows it needs information or wants another system to perform an operation. Common uses include retrieving customer or account data, creating or updating CRM records, checking order status, enriching leads, processing transactions, and searching records.
Example: A sales rep opens an account page, triggering an API request for current company information. The service returns the data for the application to display.
When to use a webhook
A webhook is an event-driven HTTP callback that sends data to a configured URL when a defined event occurs. Instead of repeatedly checking for changes, the receiving application waits for the source system to notify it.
Use a webhook when the source system knows something has happened, and another application needs to react. Common triggers include form submissions, payment status changes, email bounces, subscription cancellations, support requests, shipping updates, and completed background processes.
Example: A prospect submits a demo form. The form platform immediately sends the record to a webhook endpoint, which starts the lead qualification workflow.
When to use an API and webhook together
Use both when an event needs to trigger a workflow that requires additional data or actions. A common pattern is webhook triggers workflow → API retrieves data → business rules evaluate it → API updates another system.
For example, a demo request can trigger a webhook, which starts a workflow that calls an enrichment API for account and contact information. Qualification and routing rules evaluate the enriched record, and another API call updates the CRM and assigns the lead. This combines event-driven notification with the broader data access and actions APIs provide.
For more complex revenue workflows, see How to Build a RevOps Tech Stack for guidance on systems of record, integration ownership, and data flow.
API vs webhook: 8 key differences
The API vs webhook decision becomes clearer when you compare how each initiates communication, handles data, and supports workflows.
1. Who initiates the communication
With an API, the application that needs data or an action initiates the request. With a webhook, the system where an event occurred initiates the communication. For example, an application might call an API to check an order’s status, while a shipping platform sends a webhook when that order is delivered.
2. Request-response vs event-driven
APIs typically use a request-response model: the client makes a call, and the server responds. Webhooks are event-driven, sending information when a defined event occurs without waiting for the receiving system to ask.
3. Timing
API calls happen when the requesting system makes them, while webhooks fire after configured events. This makes webhooks useful for time-sensitive updates that would otherwise require frequent API polling.
4. Data flexibility
APIs generally give applications more control over the records and fields they request. Webhooks typically send a predefined payload related to an event, after which the receiving system can call an API if it needs additional details.
5. Polling and resource use
API polling repeatedly checks whether something has changed, generating requests even when there is nothing new. Webhooks notify the receiving application when an event occurs, reducing unnecessary requests and detection delays.
6. Failure handling
API callers typically receive an immediate success or error response. Webhooks require planning for failed or delayed deliveries, retries, duplicate events, timeouts, and missing acknowledgments because delivery behavior varies by provider.
7. Security
APIs commonly use API keys, access tokens, OAuth, and permissions. Webhooks also require a secured receiving endpoint, typically using HTTPS, signature or secret verification, payload validation, and protections against replay attacks.
8. Implementation and ownership
APIs require teams to manage authentication, requests, responses, mappings, and rate limits, while webhooks require an endpoint, sender verification, monitoring, and failure handling. Either approach needs clear ownership in a production environment.
API vs webhook for automated lead routing
Lead routing shows why the two technologies are often complementary rather than competing choices.
| Lead-routing task | Best fit |
|---|---|
| Detect a new form submission | Webhook |
| Retrieve firmographic data | API |
| Look up account hierarchy | API |
| Notify workflow of a new lead | Webhook |
| Check existing CRM ownership | API |
| Update lead owner | API |
| Trigger rep notification | Webhook or workflow event |
| Refresh thousands of CRM records | Batch/API |
Our lead tracking guide covers the software side of maintaining ownership, follow-up, activity, and pipeline visibility after the record reaches sales, while our lead scoring guide covers how sales and marketing teams can combine fit, engagement, predictive models, and buying signals before deciding which prospects deserve attention.
How ZoomInfo supports an API and webhook lead-routing workflow
ZoomInfo’s Enrich API can add company, contact, firmographic, technographic, hierarchy, and buyer data to partial lead records before scoring and routing. A typical workflow is form submission → webhook → ZoomInfo Enrich API → lead scoring → routing rules → CRM assignment. Here, the webhook triggers the workflow, while ZoomInfo’s API supplies the B2B context needed to evaluate the lead.
Teams should also define field ownership, validation, deduplication, and sources of truth. For more guidance, see our guide to CRM Data Management: Best Practices for Cleaner Revenue Data.
API and webhook security best practices
API and webhook security overlap, but the risks are not identical.
For an API, protect credentials, restrict scopes and permissions, encrypt traffic, rotate credentials when required, and monitor unusual request patterns.
For a webhook, verify that the request actually came from the expected provider. Use HTTPS, validate signatures or secrets where supported, check timestamps, reject malformed payloads, and protect against replay attacks.
For both approaches:
- Apply least-privilege access
- Validate incoming data
- Protect secrets
- Log failures
- Monitor endpoints
- Document ownership
- Test security and failure cases before production
Do not put long-running business logic directly into a webhook receiver if the sender expects a quick acknowledgment. A common pattern is to validate the event, acknowledge it, then place the work into a queue for asynchronous processing.
How to choose between webhook vs API
The right choice depends on who initiates the action, when data is needed, and what the workflow needs to do next.
1. Determine who knows when action is needed
Use an API when your application knows it needs data or an action. Use a webhook when another system knows an event occurred. Example: A user clicks “Refresh company data,” triggering an API call, while a demo form submission triggers a webhook.
2. Decide whether you need data on demand
Use an API when users or systems need to retrieve different information on demand. Use a webhook when a known event needs to send a defined update. Example: Retrieve a customer profile with an API, but use a webhook to report a subscription cancellation.
3. Determine how quickly you need to react
Use a webhook when the workflow should respond soon after an unpredictable event instead of waiting for API polling. Example: A demo request can enter lead routing immediately after submission rather than waiting for the next scheduled check.
4. Check whether you need to modify data
An API is often needed when the workflow must retrieve, create, or update a record, even if a webhook starts the process. Example: A payment webhook triggers the workflow, then an accounting API updates the invoice.
5. Check whether you can support webhooks
Webhooks require a reliable HTTPS endpoint plus authentication, logging, monitoring, and failure handling. Example: If your environment cannot reliably operate a callback endpoint, scheduled API requests may be easier to maintain.
6. Decide whether you need both
Many workflows work best with both: a webhook announces an event, and APIs retrieve additional data or perform subsequent actions. Example: A webhook announces a new lead, APIs enrich it and identify the owner, and another API call writes the assignment to the CRM.
Common API and webhook mistakes
- Polling more often than necessary: This consumes requests without improving the workflow.
- Assuming webhook delivery is guaranteed: Build for retries and temporary receiver outages.
- Trusting webhook payloads automatically: Verify signatures or other authentication controls.
- Ignoring duplicate delivery: Use event IDs and idempotent processing.
- Running slow work before acknowledging a webhook: Queue longer processes when practical.
- Using a webhook where flexible queries are needed: An API may offer more control.
- Assuming APIs cannot be fast: A directly triggered API request can return immediately.
- Skipping ownership and monitoring: Integrations need someone responsible for maintaining them.
Frequently asked questions
Is a webhook an API?
They are closely related, and webhooks typically use HTTP to send data to an endpoint. However, a webhook describes an event-driven callback pattern, while an API can expose a broader set of requests, data, and operations.
Are webhooks faster than APIs?
Neither technology is inherently faster. Webhooks can reduce the delay associated with polling because they send a notification after the event occurs. A directly initiated API request can also return very quickly when the calling system already knows it needs the data.
Can APIs and webhooks be used together?
Yes. One common architecture uses a webhook to start a workflow, followed by API calls to retrieve additional information, update records, or perform actions.
Are webhooks more secure than APIs?
No. Both can be secure when implemented correctly. APIs need authentication, permission controls, and secure credential management, while webhooks need HTTPS, sender verification, payload validation, and protections against replay or duplicate processing.