What Is an API?
API stands for Application Programming Interface. In plain English: it's how software talks to other software.
When you check the weather on your phone, your weather app doesn't have its own weather satellites. It asks a weather service for the data through an API. When you pay for something online, the website doesn't process your credit card directly - it talks to Stripe or PayPal through their API.
The Restaurant Analogy
Think of a restaurant. You (the customer) want food (data). The kitchen (the server/database) has what you need. But you don't walk into the kitchen and make it yourself. You use a waiter.
The waiter is the API. You tell them what you want, they communicate with the kitchen, and they bring back your food. You don't need to know how the kitchen works. You just need to know what's on the menu and how to order.
Why APIs Matter for Business
APIs let systems work together without manual effort. Without APIs, you'd have to: - Export data from one system as a CSV - Clean it up manually - Import it into another system - Repeat this constantly
With APIs, systems sync automatically. Your CRM talks to your email tool. Your website talks to your payment processor. Your inventory system talks to your e-commerce platform.
Common Business APIs
Payment processing - Stripe, PayPal, Square. Handle payments without building payment infrastructure.
Email - SendGrid, Mailchimp. Send transactional and marketing emails programmatically.
CRM - Salesforce, HubSpot. Create contacts, update deals, sync customer data.
Analytics - Google Analytics, Mixpanel. Track events and retrieve reporting data.
Communication - Twilio (SMS), Slack. Send messages and notifications.
Cloud services - AWS, Google Cloud, Azure. Spin up servers, store files, run computations.
How APIs Work (Simplified)
Most modern APIs work over HTTP (the same protocol your web browser uses). The basic pattern:
1. You make a request - "Give me all customers created this week" 2. The API processes it - Checks your credentials, finds the data 3. You get a response - The data you asked for (usually as JSON)
A real example - getting a customer from Stripe:
Request: `GET https://api.stripe.com/v1/customers/cus_123`
Response: ``` { "id": "cus_123", "email": "customer@example.com", "name": "Jane Smith", "created": 1234567890 } ```
You don't need to understand the code to use APIs - many tools let you set up integrations without writing anything. But understanding the concept helps you evaluate options.
REST vs GraphQL vs Webhooks
REST APIs - The most common type. You request specific resources (customers, orders, products) at specific URLs. Simple and widely supported.
GraphQL - A newer approach where you specify exactly what data you want. More flexible but more complex. Popular with modern applications.
Webhooks - APIs in reverse. Instead of you asking for data, the service pushes data to you when something happens. "Notify me whenever a new order is placed."
Integration Challenges
APIs sound great in theory. In practice, there are challenges:
Rate limits - Most APIs limit how many requests you can make. Hit the limit and you get blocked temporarily.
Authentication - APIs need to know who's calling. Managing API keys and tokens adds complexity.
Data format differences - Stripe calls it "customer." HubSpot calls it "contact." Your database calls it "client." Mapping between formats is tedious.
Versioning - APIs change over time. Your integration might break when the provider updates their API.
Reliability - APIs can go down. What happens to your business when a critical API is unavailable?
Build vs Buy
When connecting systems, you have options:
Integration platforms (Zapier, Make, Tray.io) - Point-and-click tools to connect common apps. Great for simple use cases.
iPaaS (Workato, Boomi) - More powerful integration platforms for complex enterprise needs.
Custom code - Build exactly what you need. Most flexible but requires development resources.
For most businesses, start with integration platforms. Move to custom solutions when your needs outgrow what they can handle.
APIs are how systems connect. Learn about data pipelines that move data between systems and building API integrations.
---
Sources: - Red Hat: What Is an API? - AWS: What Is an API? - MuleSoft: What Is an API?