Ever wondered how different software components talk to each other? They use APIs! I just completed my Postman certification and I'm super excited to share what I've learned.
Here's a snapshot of how APIs bridge different applications:
- Hardware API for apps to talk to your camera 📸
- Software library API for image processing 🎨
- Web API for sending images to servers for all those likes 👍
APIs come in various flavors, each with its unique strengths:
- REST (Representational State Transfer): A set of constraints that ensures stateless operations, making it easy to scale and reliable.
- GraphQL: A query language for your API that allows clients to request only the data they need.
- WebSockets: Provides full-duplex communication channels over a single TCP connection, allowing real-time data transfer.
- Webhooks: User-defined HTTP callbacks that react to specific events.
- SOAP (Simple Object Access Protocol): A protocol with predefined rules for structuring messages, typically used in enterprise settings.
- gRPC (Google Remote Procedure Call): Uses HTTP/2 for transport and Protocol Buffers as the serialization format.
- MQTT (MQ Telemetry Transport): A lightweight messaging protocol for small sensors and mobile devices.
APIs can be categorized based on their accessibility:
- Public APIs: Open for the world, they can be discovered and consumed by any developer out there.
- Private APIs: These are the internal workhorses, consumed within an organization and shielded from external access.
- Partner APIs: A bridge between organizations in a partnership, facilitating collaboration.
For instance, Instagram's API that fetches user photos is a RESTful public API!
In the course, we will be using Public, REST, and Web APIs 👀
Here's how to make the most of Postman's features:
- Create a Workspace: Think of it as your personal playground to test and develop APIs.
- Create a Collection: Organize related requests together. It's like a folder for your API calls.
- Add Request: Specify the kind of operation you want, be it GET, POST, PUT, or DELETE. Remember, PUT generally replaces an entire resource, whereas PATCH typically updates parts of a resource.
Tired of typing the base URL repeatedly? Use variables in Postman!
- Replace values, especially sensitive ones.
- Access them with curly braces:
{{variableName}}
- Query Parameters: These are the extra knobs and dials for your API calls. They fine-tune the request based on key-value pairs and are appended to the URL after a
?, separated by&. - Path Variables: They pinpoint specific resources in your API calls. For instance,
/users/{id}might target a user with a specific ID.
Beyond just fetching or sending data, HTTP methods dictate the kind of operations:
- POST: Create a new resource.
- GET: Retrieve existing data.
- PUT: Update or replace an existing resource.
- DELETE: Remove a resource.
Think of these methods as the "address" on your envelope, guiding how the data inside should be treated.
Unlock the power of automation in Postman:
-
Variable Scopes: Local, global, environment, data, and local-specific.
-
-
Scripting in Postman: Supercharge your API calls by adding dynamic behavior.
- Pre-request scripts: Executed before a request is sent.
- Test scripts: Run immediately after receiving a response.
Harness the pm object in Postman to access, set, or modify variables dynamically.
In the realm of APIs, 'Authorization' is paramount. Here's a brief on the methods I explored with Postman:
- Basic Auth: Uses a username and password combination.
- OAuth: Offers delegated authorization.
- API Keys: Secret strings given to a developer from an API portal.
These methods ensure that our API interactions are not just efficient but also secure.
Ever wanted to integrate your API calls directly into your app? Postman's codegen feature translates your API requests into code snippets in various languages, easing integration.