An API and an integration are not the same thing. An API (application programming interface) is a defined way to reach a system's data and actions. An integration is the implemented connection or workflow that makes systems work together. An API integration uses an API inside that connection. The key point for a buyer: having an API does not decide which records move between your systems, how fields are mapped, or what happens when something fails. Many ready-made integrations use APIs under the hood, so you rarely choose one or the other.
Below: the exact difference, a worked example, your options, and a checklist to use before you scope a project.
API, integration, API integration, and connectors
The words get used loosely. Here is what each one means and what a working business process still needs on top of it.
| Term | What it is | What a working process still needs |
|---|---|---|
| API | A defined interface to a system's data and operations | Rules for which records move, how fields map, and what to do on failure |
| Connector | A reusable component that connects to a system or data source through an API or another supported interface | The surrounding workflow, mapping, and error handling |
| Integration | The implemented connection or process that makes systems work together | Clear ownership, monitoring, and change management |
| API integration | An integration that uses an API to exchange data | Rules for access, data handling, failures, and ongoing support |
Not every API is public, and not every API is web-based. This guide stays on the common case: connecting business applications so data flows between them. A native integration is a ready-made connection a vendor builds in; what it covers depends on that vendor. A connector can also work with files or databases; it is not limited to APIs. MuleSoft's explanation of connectors and integration applications describes this distinction.
A worked example: a paid order reaches your CRM
Picture a simple goal: when a payment is confirmed, update the customer's order status in your CRM.
The payment service sends an event notification, often called a webhook. The integration verifies its source, identifies the order and customer, maps the fields to the CRM's format, updates the CRM record, and records the result. The API is the interface to each system. A connector or custom code carries the data. The business logic decides what a "paid order" should change.
Now add three real-world events, because this is where "has an API" stops being enough:
- The notification arrives twice. Delivering a message twice is not the same as repeating the business action twice. You need a way to recognize an event you already processed so it does not create a duplicate CRM activity or trigger the same follow-up twice.
- The CRM is briefly down. The update must be retained for recovery. A queue with limited retries can handle temporary failures; unresolved errors need an alert and a recovery path.
- The CRM saved the record, but the response was lost. The result is uncertain. The integration needs a safe way to retry the operation or confirm its outcome using a stable order or operation ID. Reconciliation compares the expected result with the CRM's actual state. A simple check followed by another write is not enough if two workers can act at the same time.
This is where idempotency matters: repeating an operation has the same intended effect as carrying it out once. The implementation depends on the API and the workflow. Stripe's webhook documentation gives a concrete example of why handling duplicate events matters. Reliable exchange requires rules around the interface, not just access to it.
Native integration vs API: which approach fits?
A native integration often uses APIs internally. The practical choice is whether an existing integration covers your process or whether you need to configure or build one. There is no option that is always simpler or always more reliable. Compare them against the operations, fields, direction, frequency, error handling, support owner, and limits your process actually needs.
| Option | When to consider it | What to check |
|---|---|---|
| Native (built-in) integration | The process you need is already supported | Fields, objects, direction, latency, plan, and support |
| Integration platform with connectors | You can assemble the process from supported actions | Action limits, configuration, run history, recovery |
| Custom integration | You need logic or control the ready-made options lack | Available interfaces, operations, testing, rights, owner |
A cloud service for connecting applications and assembling workflows is commonly called an iPaaS, short for integration platform as a service. Its connectors help you assemble a workflow, but you still need to configure and verify that workflow.
The exchange method is a separate choice. For example, a nightly inventory-file import can suit a process that tolerates a daily update. Check the file format, secure delivery, failed imports, and how you will compare the results. A custom or platform-based integration can use this approach.
API development can be one part of an integration project when a system you control does not expose the operation you need. Building your own API also does not remove another vendor's limits. A custom process can use APIs, files, messages, and other permitted interfaces together. For a full product build around these pieces, see web application development.
API integration checklist: what to check before you commit
Use these questions to scope the project. For each answer, record the relevant documentation or test result and the person responsible. You do not need webhooks or a separate sandbox in every project, and no approach is real time by default.
Access and data
- Which objects and operations move, and which system holds the main version of the data (the system of record)?
- What access is needed, and on which plan? Check approval steps, permission scopes (which actions are allowed), and whether specific API operations need a higher plan.
- Who grants and revokes access, and how are secret keys stored and rotated?
The exchange
- One direction or two? Does it create, update, and delete records?
- What delay is acceptable: seconds, minutes, or a scheduled batch? How many requests does the API allow, and what happens when you reach that limit?
- How will you load existing records, including pagination (retrieving results in batches)?
Errors
- What happens on a repeated event, so a business action is not run twice?
- What happens if a response is lost after the record was written?
- How are missed records found later (reconciliation), and who recovers them by hand?
Operations
- What exactly does the test mode allow: an isolated environment, request validation, or something narrower?
- Who sees an error and fixes it? Is there a log and an alert?
- How will you learn when the API changes (a changelog or deprecation notice)?
What vendor documentation can and cannot tell you
Read documentation for the specific API, version, and plan you intend to use. A feature described somewhere on a vendor's site may belong to a different product or interface.
For example, Twilio SendGrid's Sandbox Mode validates a Mail Send request without delivering the email. It also does not generate Event Webhook or Email Activity events. That makes it useful for checking the request, but it cannot test an entire delivery-and-notification workflow.
Ask which parts of your process a test environment actually exercises. Even an isolated sandbox can differ from production. If the reviewed documentation does not answer a question, confirm it with the vendor rather than treating silence as proof that a feature is missing.