JSON vs XML

Both JSON and XML are data formats used to send and receive data from web servers.
Both play an important role in organizing data into a readable format in many different languages and APIs.

JSON is short for JavaScript Object Notation. 
It: 
 - is based on JavaScript object literal syntax
 - can be easily parsed into a ready-to-use JavaScript object with no library needed
 - is easy to read and write
 - is supported by most backend and modern programming languages

XML
- Extensive markup language that allows creating custom user defined tags
- Manages data in a tree structure hierarchy
- Complex data structure that must be parsed

JSON vs XML: Similarities and Differences

Generally, JSON is considered better than XML

GraphQL: A Visual Exploration Of It's Benefits

Let's discuss GraphQL and some of the benefits it has on offer

What is GraphQL and what does it do best?

Let's go through some of it's major benefits.
Benefit 1: Strongly Typed

Benefit 3: Reduced Over-Fetching and Under-Fetching 

REST API Development Tips

Always name resources consistently. Following a naming pattern will allow users of your API to assume endpoint names, making it easier to use and much more structured. As a best practice rule for naming endpoints, always use nouns to name and not verbs, and always use plural nouns for resource collections to clearly indicate that the endpoint contains multiple resources.

Pagination and filtering are two great techniques you can use to enhance your API's performance. Particularly with APIs with large databases, data retrieval can be slow. To combat this you can apply pagination which sorts data out into manageable pages instead of delivering one large dataset. 

Another important tip is to secure your API well. API data can be vulnerable to various attacks, so if your API deals with sensitive data, security is the number one priority. You should apply various security measures to minimize risks and not just one type. Trusted authentication methods include OAuth and API Keys. Basic HTTP authentication should be avoided.

Rate Limiting is another very important technique to apply to your API because it acts as a defense mechanism against request overload. Rate limiting limits the number of calls a user can make to your API per period. If the call rate is exceeded, the user will have their connection blocked and must either wait for more calls or pay for more. This is very useful in cases where you might receive a request influx (bot attack/ DoS attacks) that if left alone, can overload your API with traffic and render it useless.

When structuring your API, it's important to think of the relationship of each resource to the other and build an API with a clear resource hierarchy. This makes the use of your API easier and the structure easier to comprehend.
 
When errors occur in your API requests or responses, you should make sure to include HTTP status codes in error responses. Doing this allows users to understand the issue, diagnose the problem, and fix it more quickly. Without this additional error information, your API responses are difficult to understand and their user-friendliness decreases.

As a final tip, thoroughly plan and create documentation, and do not overlook it as part of the API building process. Well-written documentation is vital for others to be able to understand how it works, how they can implement it, and how to solve any issues that may occur as they use it. It should act as a user manual, and a first point of call should they have any questions about your API.
 
Good documentation should include info on endpoints, methods, and parameter options. It should provide code snippet examples in various programming languages, debugging details for common errors, an FAQ section, and links to external resources if required. Don't forget to also keep documentation updated as your API evolves!

HTTP Methods: PUT vs PATCH

APIs use several HTTP Methods to create, read, update, and delete data. Two of these methods - PUT and PATCH are used to update and modify data. However, they both do this in slightly different ways. To summarise their difference, we can say that PUT uses the request URI to deliver a modified version of the resource that completely replaces the original. On the other hand, PATCH only partially updates a resource without needing to modify the entire resource.

The PUT method works by completely replacing the original resource with the updated version. If the resource already exists, PUT replaces it. If it does not exist, PUT creates it.

Alternatively, PATCH applies partial updates to resources. The client only needs to send the data intended to be modified in the payload of the request and the rest of the resource remains unchanged. Since PATCH requests typically send minimal data that simply 'patches' a resource, it uses less bandwidth than PUT.

In general, it's best to use PUT only when a whole resource requires updating. Using PUT to update only a few, or even just a single field of a resource often uses unnecessary bandwidth.

API Versioning

API versioning is the process of making changes and updates to your API. It is an essential part of API management, and a good versioning strategy will allow updates to occur without disrupting the consumer experience. The aim is to steadily introduce new features, avoid large updates, and maintain functioning.

Why is versioning your API important? As an API evolves and develops, you will make changes and add new features. Even minor changes can have a domino effect and impact programs that use your API services. Such changes that could cause problems are called breaking changes.

What exactly are breaking changes? They could be removing a resource, changing a resource name, changing a resource data type, changing data format (e.g. JSON to XML), and more.

When should you version an API? It is considered best practice to versioning an API only when breaking changes are made. Non-breaking changes alone do not require versioning. Instead, they can be included in more major updates.

The first versioning method is called URI path versioning. With this method, the API version is included in the URI as v1, v2, v3, etc. This method is widely used and straightforward to implement, but it's important to keep previous versions active after new ones have been introduced.

The second method is query parameters. Similar to the URI path, the version is included in the URI, but as a query parameter. This method allows the version to be requested at the resource level. If no version is specified, you can default to the latest version.

The final method we'll look at is custom headers. In this method, the URI remains unchanged and the version number is set using a custom header in requests and responses. You can use the 'Accept-version' header followed by the version number.

Whichever method you choose, it's important to allow backward compatibility. This means keeping previous versions active not only as a backup in the case of breaking changes but also for users who decide to update in their own time.

Types of API accessibility

When we talk about API accessibility, we are referring to the level of scope the API has. There are three main types of accessibility. These are Public, Private, and Partner. Each type has different build priorities, and which level of accessibility is best depends on the API's purpose.

Public APIs (also called external or open APIs) are available to anyone. They follow a standard setup to be accessed, and then their data is freely available to individuals and organizations that want to utilize it. The goal of public APIs is to drive value and attract consumers. They can also be monetized. You can find public APIs on API Hubs like RapidAPI Hub.

Private APIs (also called internal APIs) are not intended for use outside of the organization they were built for. They are not externally available and are kept within the boundaries of their owner. This means they often deal with private sensitive data too. Many companies use private APIs for data sharing between various departments in an organization because its convenient, secure, and scalable. Some companies may start out with private APIs with the aim of eventually making them public, depending on their purpose.

Partner APIs are externally available to only a select group of strategic business partners. This means they sit between public and private. They deal with sensitive data, and often have stricter security to ensure only authorized organizations can access them. This way data can be shared whilst also keeping tight control of resource access.

The difference between Authentication and Authorization

In a nutshell, authentication is the identification of a user, and authorization controls what a user can access.

You can think of authentication as needing to show your passport at the airport to verify who you are. On the other hand, authorization is like your boarding pass, which controls which flight you can take from within the airport.

Since APIs cannot identify individual users, authentication methods involve authenticating the application requesting the data. The most commonly seen authentication methods are OAuth, API Keys, and basic HTTP authentication.

As for authorization, it is usually predefined by the organization or application settings. There are however access models used to define authorization rules. 

The two most common access models are RBAC (Role-Based Access Control) and ABAC (Attribute-Based Access Control), which are commonly combined with each other or other authorization methods. Authorization always comes after the process of authentication.

HTTP Status Codes

HTTP Status Codes are three-digit codes that are returned in server responses to HTTP requests. Status codes tell the client about the status of the request, whether it was successful, and what the problem is if there is one. Understanding status codes is very helpful as it allows you to quickly diagnose errors. Some status codes even greatly impact SEO and the search engine's ability to crawl your site's content.

As a reminder, this is the basic structure of an HTTP response. You'll always find the status code in the appropriately named status line.

There are five groups of status codes to know about. These are 1XX, 2XX, 3XX, 4XX, and 5XX. Each group represents a different type of response from a server.

Starting with 1XX. These are informational responses. They are rarely seen because they are issued when a request is being processed and not in the final HTTP response. As an example, Status code 100 'Continue' indicates the request is being handled and the client can continue.
 
The next group is 2XX which indicates successful responses (the server delivered the expected response). For example, status code 200 'OK' indicates a perfectly successful request. Status code 201 'Created' indicates a successful request where a new resource was created. This is typically a response to POST or PUT requests.

3XX responses indicate redirection is required. The resource or page requested was found, however, not at the expected URL. Most redirection responses include the actual URL the resource was found at, which should be used to make future requests. As an example, 302 'Found' indicates the URI has temporarily changed and may change again in the future.
 
4XX codes are for client-side errors. They indicate the resource/page could not be found. This could be due to non-existent resources, unauthorized clients, or too many requests. 400 'Bad Request' means the request was invalid, and 404 'Not Found' means the requested URL is not recognized.

The final group is 5XX. These are server errors. They can occur if the server is down for reasons such as maintenance or too much traffic. They can also indicate unknown server problems. 500 'Internal Server Error' indicates an unknown server error, and 503 'Service Unavailable' indicates the server is temporarily down but will return to functioning later.

API Specifications

API specifications are documents that outline how an API should work to standardize them for use across different platforms and programming languages. You can think of API specs as blueprints for structuring and building APIs.

Standardized APIs have the ability to be diverse. Specifications are therefore important for defining how APIs interact with each other across various operating systems and languages. One of the most widely-used specs for REST APIs on the web is the OpenAPI specification. In total there are four types of specs for different types of APIs: REST, GraphQL, SOAP, and RPC.

So why is it important to start building an API by following a specification? Because specs define how your API should look structurally, you can isolate and avoid certain design flaws from early on in the API creation process. This saves you time during development and avoids the risk of inconsistency.

Here are the benefits of following a specification. Firstly, many specs provide tools for test and documentation generation, both of which are necessary when building an API of industry standards. 
 
Secondly, most specs are in JSON or YAML format, so can be easily read by both humans and machines. This also makes them more accessible to other teams and departments such as product management. 

Finally, following a spec creates consistency, and your API is built to a universal standard. This maximizes accessibility, and discoverability, and creates an overall better developer and consumer experience.

The CRUD Model

CRUD is an acronym for Create, Read, Update, and Delete. These are the four basic operations we use to manipulate data using APIs. HTTP also follows CRUD functionalities, which means REST APIs utilize this too. Other popular database technologies like SQL and GraphQL also have CRUD operations as their foundation. CRUD operations are vital in API building and database technologies because they enable effective data interaction and manipulation.

Here is the first of the four CRUD operations: Create. This action allows new resources to be created and added to an existing database. The HTTP equivalent is the POST method.

The second operation is READ. This action allows us to retrieve and view current data without altering it. The HTTP equivalent is the GET method.

The third operation is Update. This allows specific data to be altered and modified. The HTTP equivalent is the PUT method.

The final operation of CRUD is Delete. This implies resources can be removed from the database system entirely. As implied, the equivalent HTTP method is DELETE.

Rapid 100K Developer Community

Rapid's Developer Community is 100K strong!

As one of the biggest and most engaged API Developers communities, we'd like to say "Thank You" to everyone for trusting us on building excellent developer tools. 

What do you like most about Rapid?

🔹 RapidAPI Client extension for VSCode
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We hope you'll continue to learn and grow with us! 

FIFA World Cup APIs

Follow the FIFA World Cup action with APIs!

Check out Rapid API Hub to view, test, and use the latest FIFA APIs like these.

RapidAPI Hub has seen a recent increase in activity for sports and soccer APIs as demand for World Cup data has increased. As a project, try making a World Cup application yourself!

API Rate Limiting

What is rate limiting? Rate Limiting restricts the number of API calls a client can make at a given time. Implementing rate limiting on your API is considered a best practice as it has many benefits. 

Why rate limit APIs? API owners want to ensure their API is functioning as efficiently as possible and that no single client overwhelms the API with an overload of requests. Influxes of requests impact performance and can affect other clients. Rate limiting prevents this and keeps the flow of requests under control. If an API uses many resources, rate limiting also keeps costs under control.

You can think of rate limiting like traffic lights controlling traffic flow. Similarly, rate limiting controls the traffic flow to your API. Without rate limiting, network traffic is unregulated and can potentially overload a server and cause problems and poor functioning.

When a server is rate limited, network traffic is managed efficiently, and latency is minimized. Functioning is maintained during activity spikes and single clients sending influxes of requests are disconnected. 

When a server is not rated limited, latency is higher, and services are at risk of DoS (Denial of Service) attacks and bot attacks, which will cause traffic overload and leave services inoperable.

Let's look at some common rate limiting methods. The first is throttling. In this method, the throttling algorithm will first assess if a request exceeds the enforced rate limit. If it does, the throttle is triggered, and the client will either have their bandwidth reduced or be disconnected entirely.

The next method is request queuing. Requests are limited to being handled at a certain number per given time, e.g., two requests per second. Excess requests are then queued. Many libraries can implement request queuing for you.
 
The final method is rate limiting algorithms. There are various algorithms that can implement rate limiting. All of them are slightly different but implement efficient and trusted rate limiting. Some common algorithms are leaky bucket, fixed window, and sliding log.

GraphQL Best Practices

Learn GraphQL best practices in this week’s RapidAPI Comic!

1. Use HTTP 

GraphQL is typically served over HTTP and a single endpoint. So HTTP is recommended to support GraphQL capabilities.

2. Pagination

Pagination optimizes performance. GraphQL has various API design possibilities for pagination.

3. JSON and GZIP

GraphQL services typically use JSON, which can be compressed by enabling GZip. JSON is also familiar to API developers, easy to read, and debug.

4. No versioning

The GraphQL Schema supports the continuous evolution of APIs. So although you can version them, it's not recommended. 

5. Nullability

GraphQL fields can be nullable or non-nullable, but all fields are nullable by default. Selecting certain fields to be non-nullable guarantees the client that those requested fields will not return null.

An Introduction to CORS

What is CORS? As a standard, all browsers implement a Same-Origin Policy for security reasons. This is where requesting data from the same origin is allowed, but requesting data from another URL throws an error. CORS (Cross-Origin Resource Sharing) is an HTTP-based mechanism that allows us to request data from other URLs.

In its most basic form, a CORS request involves a request from the browser to another domain's server and that server responding successfully or unsuccessfully.
  
In the request, an 'Origin' header is sent declaring the domain making the request. The server responds and adds an 'Access-Control-Allow-Origin header in its response. If the origin here is the same as in the request, access to the resource is given.

Some HTTP Methods (all except GET, POST, and HEAD) require a preflight request before the main CORS request is made.
 
A preflight request starts with the browser making an HTTP OPTIONS request to the server with the proposed request method of the main request in the 'Access-Control-Request-Method' header.

The server responds with an 'Access-Control-Allow-Method' header, stating the accepted request methods. If the method sent in the request matches here, the preflight request is accepted, and the main CORS request follows. If the method does not match, the entire request fails here.

An example of a CORS request with a preflight request would be a website making an AJAX call to POST JSON data to a REST API.
  
Some preflight responses may contain an 'Access-Control-Max-Age' header specifying the time the response must be cached within. Using this header means the client won't need to send a preflight request every time it wants access to the CORS resource.

How API Requests Are Cached

What is cache? Caching means storing responses in cache memory. These stored responses can be reused in subsequent requests as opposed to requesting them from the server again.

What is the purpose of cache? Caching avoids unnecessary network requests by retrieving resources from the cache instead of via repeated server requests. Doing this lowers latency and improves API performance.

How does caching work? Cache is controlled by the HTTP Cache-Control header, which has several directives that dictate the cache conditions. For example, the 'max-age' directive defines how long a resource will remain cached in a browser in seconds. Once 'max-age' has expired, the cache is cleared, and the resource must be requested from the server when it is next needed.

How API calls are cached: the client makes a GET request. The resource requested does not exist within the cache, so it goes to the server. The server delivers the resource with a 'Cache-Control: max-age: 1800' header in its response. The resource is then stored in the browser's cache until 1800 seconds have passed. Until then, subsequent requests for the resource are only retrieved from the cache.

Here are some additional Cache-Control directives to be aware of. 'public' indicates a resource can be stored in a shared cache, such as a CDN cache, even if it requires HTTP authentication to access.
  
'private' indicates the resource is intended for a single user only and, therefore, cannot be stored in public caches. Instead, it is only stored privately, e.g., in the user's browser.

'must-revalidate' prevents the use of stale resources. Stale resources must be invalidated against the server before being delivered to the client.

'no-store' prevents all browsers and intermediate/shared caches from storing the resources (resource is not cacheable).

'no-cache' allows caching but forces the browser to revalidate the resource against the server on each request.

Here's an example of a typical Cache-Control workflow.

API Security Best Practices

1. Authentication. This is probably the most vital security measure. Always use secure and known authentication methods such as OAuth, JWTs, and API Keys. Using only basic HTTP authentication is not recommended, as user credentials are sent with each request to authenticate it. For this reason, basic HTTP authentication is considered the least secure method.

2. Validate input. Input validation is a way to ensure incoming data to your API follows an expected format and is, therefore, not malicious. Incoming data not following the expected format could be improper entry attempts such as SQL injections or cross-site scripting. Validation can be implemented on syntactic (enforces syntax correctness) and semantic (enforces correctness of values) levels.

3. Use an API Gateway. API Gateways are an all-in-one way to implement security, monitoring, and overall API management. They are a single entry point for all API calls and sit between the client and several backend services that handle requests appropriately.

4. Use rate limiting. Rate limiting is a way to protect server infrastructure if an influx of calls occurs, such as in a DoS (Denial of Service) attack. With rate limiting, clients sending an influx of requests will have their access blocked after exceeding the maximum call rate, preventing the API from being overwhelmed.

5. Only share required data. Your API should return the appropriate data only and nothing unnecessary. Double-check the data your endpoints return and ensure no security information, such as an API Key, is included. You can also remove 'X-Powered-By' response headers, as they leak server-side information that could potentially aid attackers in exploiting your API for valuable data.

Anatomy of an HTTP Response

HTTP responses are made by a server in response to a client's request. They inform the client about whether the request was successful; if not, they provide error information. They also deliver resources to the client if that's what is requested. There are three components to an HTTP response. 

The first part is the status line. This displays the HTTP version in use, followed by an informative status code indicating how the server handled the request. For example, a '200 OK'code means the request was successful, '404' indicates the requested resource was not found, etc.

The second part of a response is the HTTP response headers. There are various headers to provide extra information about a response. There are headers for security, content, caching, date and time details, and more.

The last part of a response is the body(data). This part is optional, depending on the type of request sent. The body contains the data that is being sent back to the client. This could be an image, text, JSON, etc. In the response structure, there is always a blank line that precedes the body.

An HTTP response fully constructed with its's three parts: The status, headers, and body.

The server sends the response to the client as a reply to its request.

What is SSL/TLS?

SSL and TLS are standard security protocols used for secure network communication. SSL(Secure Socket Layer) was first created in 1996 by Netscape. After noticing its security flaws, TLS(Transport Layer Security) was created as an updated replacement. The most recent release was TLS 1.3 in 2018. Today the terms SSL and TLS tend to be used interchangeably.

Websites that require security or personal information like passwords, bank details, etc., will always have a URL starting with HTTPS and not HTTP. HTTPS indicates the site is secure because it has an SSL/TLS certificate. These certificates allow the client to authenticate the server and establish a secure, encrypted connection.

Websites that have an HTTP-only connection exchange data in plain clear text. This means potentially personal information travels across the public internet unencrypted. Attackers that intercept network traffic and filter them for data can see all your information exposed and readily available to exploit. For this reason, HTTP-only sites receive much lower SEO rankings.

So how do SSL/TLS certificates work? The client initiates a connection by sending a 'Hello' message. This contains the supported TLS version, supported cipher suites, and a random string called the client random. 

The server then responds with its own 'Hello' message containing the cipher suite, another random string called the server random, and its TLS certificate.

The client then authenticates the server. Using a key in the severs TLS certificate, the client encrypts a string called the premaster secret and sends it to the server.

The premaster secret can only be decrypted by a private key on the server. Once decrypted, the server generates session keys from the client random and the server random that were sent in the 'Hello' messages. Session keys are exchanged, and the encrypted session is established.

The TLS connection uses irreversible encryption algorithms to scramble all the data being passed between the client and the server, protecting it. 

On today's internet, HTTPS is an essential security practice. It is now standard practice for all websites to use HTTPS even if the site does not use personal data. Using sites with HTTP only is a significant deterrent for users, and search engines penalize HTTP-only websites in SEO rankings to discourage their use.

How to write excellent API documentation

How to write excellent API documentation.

Well-written documentation is a vital part of the API building process. Without it, your API service becomes more challenging to implement and understand, deterring potential users.

Here are six points to include in your documentation. First is an introduction/overview of what your API does. It should be short and precise. This could also be a getting started section. 

Secondly, include code snippets throughout the docs in several different programming languages to demonstrate use.

The third point is tutorial explanations. Code snippets alone are not enough. You should also explain clearly what the code is doing, provide details on parameters and methods, and provide example HTTP requests with their expected responses.

As a fourth point, give information on authorization details, access to credentials, API Keys, tokens, etc. Remind users of all basic API security best practices.

The fifth point is always to include error details and debugging solutions. Explain common errors, which endpoints will return which error codes, and provide standard solutions. 

As a final point, always provide links to external resources. If your API requires external tools such as npm, or OAuth, link the appropriate documentation. Your documentation should be accessible, regardless of the user's skill level and technical knowledge.

If you want to enhance your documentation further, consider adding a Glossary, comments section, FAQs section, and a contact section. It's essential to note that your documentation should be well structured. Avoid large blocks of text and overly technical writing. It should also be openly accessible, not only to registered users.

Cookie Authentication

What is cookie authentication? Cookie authentication authenticates client requests using HTTP cookies. This means the server can maintain sessions over HTTP, which is otherwise stateless (each call to the server is independent of the other).

How does cookie authentication work? First, the client sends a login request which contains all the login credentials needed for the server to authenticate. Then in its response, the server sends a 'Set-Cookie' header which contains cookie data such as ID, expiry, and more.

Now, with each request to the server, this cookie is sent every time. The session ends once the client logs out, and the server then sends back the 'Set-Cookie' header, causing the cookie to expire.

There are some limitations to cookie authentication. Firstly, it is not protected from Cross-Site Reference Forgery attacks (CSRF). It is highly recommended to use CSRF tokens as a security measure if you use cookie authentication. 

Cookies also work on a single domain only. This can cause issues if, for example, an API service originates on different domains for different platforms (e.g., web and mobile)

API Security Risks

Excessive data exposure is when an API returns too much unnecessary information in a response. Too much sensitive data exposed could be taken advantage of by attackers. Data should always be filtered on the server side and never over-exposed on the client side.

Broken Authentication. Poorly implemented authentication could mean short, infrequently updated API keys, lack of access token validation, non-expiring JWTs, and more. It's essential always to use multifactor authentication and follow industry best practices.

Lack of resources and rate limiting. Without rate limiting, APIs are vulnerable to bots and DoS attacks that can break them by overloading them with requests. Effective rate limiting and payload size limits control the number of calls able to be made within a short amount of time, and excessive calls can be blocked.

Insufficient monitoring. A lack of consistent monitoring can lead to attackers going unnoticed while probing for weaknesses. For this reason, it's important to use monitoring and analysis tools that can provide details on clients and log events such as failed access attempts.

Broken-Object level Authorization(BOLA). BOLA happens when there is improper authorization when validating access to data objects. This is when an attacker imitates another user by modifying an API request and accessing another user's information via the API.

Improving API Performance

Pagination breaks significant responses up into 'pages.' It can also be used to organize and categorize results. APIs that return large amounts of data are slowed down, but pagination limits the number of results to help keep network traffic manageable. 

Synchronous logging slows a system down by sending individual logs more frequently. In contrast, asynchronous logging gathers several logs before pushing them to the logging files. Although better for performance, asynchronous logging can cause some logs to be lost if an error occurs before the accumulation is pushed.

Database connection pooling is used to reduce the burden of constantly opening and closing database connections, which is slow and costly. Several connections are kept continuously open, and clients can connect and disconnect with them as they please. This improves performance and scalability.

Caching stores frequently used data in the browser. This means it can be quickly retrieved from the cache whenever needed. The alternative is to make another call to the server to retrieve it, so caching is a great way to reduce unnecessary calls to the server and improve performance.

There are various methods of payload compression, a popular way being GZIP. Compressed data has minimized download size and increased upload speed. Without it, large and heavier payloads reduce performance.

API Life Cycle Management

API life cycle management means managing and maintaining an API from its design and creation to its eventual retirement. Doing this effectively can maximize the functionality and success of your API.

The API life cycle can be split into seven parts. The first is design. Design is where a specification is decided, and security protocols are defined. Most web APIs follow the OpenAPI specification. Using a specification has benefits such as standardization and portability. 

Development is the next stage. Development is guided by schemas stated in the specification. This stage benefits from collaborative tools and workspaces.

Next is Secure. The appropriate level of security for your API will depend on whether it is external, internal, or hybrid. Standard security methods include OAuth, API keys, and IP safe listing. Security controls API access, so monetization may be considered at this stage.

Now you can publish your API so that it is available to clients. By this stage, documentation and testing should be complete.

Next is to monitor your API. Doing this after its publication is vital to ensure it performs as expected. Using analysis tools, you should check and test any new changes through CI/CD pipelines and monitor results.

Next, if you decide on monetization, you can decide on a type of plan. You can do a pay-as-you-go service where the number of API calls is limited based on the plan, or it can depend on the marketplace where your API is published.

The final stage is retirement, also called depreciation. An API is depreciated once it no longer receives updates, bug fixes, or maintenance of any kind. Usually, this is because new software is introduced that is incompatible with older services.

What are API Keys?

API Keys are unique alphanumerical strings assigned to clients that grant them access to an API and its services. API keys provide client authentication and authorization to reduce the risk of API attacks.

APIs authenticate a project using the unique API key to identify the application requesting to use it. An API does not identify the person requesting access (user authentication) but rather the application (client authentication). 

API Keys also identify a client's level of authorization. For example, clients on different payment plans for the same API will have different access to the service, such as restrictions on API calls.

The API owner can also use API Keys to monitor, log, and track client behavior. This is an important security measure, as attackers or bots can be identified and filtered out or even denied access.

APIs can give access to potentially sensitive or personal data. If this is the case, keeping API Keys hidden is vital to prevent data exposure. Never expose your API Keys in public or client-side code. Instead, always deal with API key credentials in server-side code or use methods like environment variables.

RapidAPI Studio

RapidAPI Studio is our all-in-one-devtool for a collaborative API developer experience.

RapidAPI Studio streamlines the API developer experience by making it smooth across various platforms.

Collaborate via different platforms to design, develop, and create various tests to monitor and track your API's performance.

Publish your APIs straight to RapidAPI Hub and manage monetization settings such as subscription type and payout.

API projects sync through the cloud on various platforms, including our RapidAPI Client VS Code extension, so you can develop without needing to leave your IDE.

RapidAPI Client for VS Code

Below are all the features of RapidAPI Client for VS Code.

Test and call APIs whilst developing - send requests and view responses without needing to leave VS Code.

Our extension adapts to your VS Code theme, so you can continue using your favorite.

Add authentication with supported environment variables.

Request code snippets in up to sixteen different programming languages and use them straight in your code.

Generate interfaces from Typescript, Python, and Swift.

RapidAPI Client for VS Code is available to install from the VS Code Marketplace!

What is HTTP?

HTTP stands for Hypertext Transfer Protocol. It is the foundation of the Internet and how it functions and exchanges data.

HTTP works in a Request and Response system. The client requests a specific resource from the server, and if the resource is available, it will be returned in a response from the server.

The response from the server will include an HTTP Status Code. This lets the client know the details of the response, whether it was successful or not, and why. Status codes are grouped into different numbers each indicating different response types. For example, codes 200-299 mean successful, and codes 300-399 indicate redirection.

When you load a web page in your browser, the requests are sent to the corresponding server to fetch the various components of the page. Each request returns an individual response.

HTTP has many features that make it the most widespread transfer protocol. HTTP is an application layer protocol based on TCP, a secure transport layer protocol. HTTP is also stateless, meaning each request and response cycle is separate from the ones before and after.
 
HTTP also enables the use of HTTP Headers in requests and responses, which allow them to be customized and provide extra information. HTTP also has a secure version - HTTPS- the standard network connection on the Internet.

The Anatomy of HTTP Requests

HTTP Requests typically contain three things: a request line, header fields, and a body(This one is optional).

The request line is composed of three parts. Firstly, the HTTP Method, such as GET, POST, or DELETE. Secondly, the resource URL. This locates the requested resource on the server. Thirdly, the current HTTP version. The request line is like the foundation of a request, like a pizza base.

The second layer to our pizza is HTTP Header fields. These provide extra information to the server about the request. There are many different headers—for example, Content-type, which indicates the data format. Content-length indicates the length of the data in bytes. Accept-Language indicates the language of the content accepted by the client.

The last part of the request is the body(data). This part is usually only needed if the HTTP Method is POST, PUT, or PATCH because it contains the new data being sent to the server. For example, in a POST request, the body could contain the details of a pizza order form.

Let's review the structure of an HTTP request in full. First, there's a request line that contains the HTTP Method, resource URL, and current HTTP version. Secondly, the HTTP Header fields provide extra information about the request. If the request is GET, this is all the information needed. However, if the request is POST, PUT, or PATCH, there is a body containing a message. An empty line always separates the Headers and the body.

That's the anatomy of an HTTP Request! It is now ready to be sent to the server.

JSON vs. XML

JSON and XML are data formats that send and receive data from web servers. They play an important role in organizing data into a readable format in many different languages and APIs.

JSON is easy to read and write, supported by many programming languages, and easily parsed into ready-to-use JavaScript objects. It uses arrays to store data based on JavaScript object literal syntax.

XML means extensive markup language. XML has a complex data structure that has a 'tree' hierarchy. XML uses custom user-defined tags to organize data.

JSON and XML are hierarchical, can be parsed in many different programming languages, and self-describing(human-readable). 
They also have significant differences. XML is tedious to parse compared to JSON which is much faster. JSON object has a type, whereas XML is typeless. XML has media display capabilities, unlike JSON. Finally, JSON is considered less secure than XML.

Most developers prefer to work with JSON because of its simplicity to parse into ready-to-use JavaScript objects.

How API Endpoints Work?

RapidAPI Comic cover: How API endpoints work.

What is an API endpoint? Endpoints are the communication touchpoint between API and server. They are URLs that users interact with to access specific resources. They typically look like this: 

```
pets/dog/snacks/bone
```

Endpoints dictate a resource's location and are where the request is sent. Each endpoint locates a different resource. Image shows a dog being commanded to fetch the resource for dog/snacks/bone and then finding the bone.

Its critical endpoints are named after the entity they represent to avoid ambiguity around naming and errors. Image shows the dog knowing the location of various snacks that are appropriately named, for example, dog/snacks/steak, dog/snacks/chicken, dog/snacks/fish.

If endpoints are inaccurately named, the API will not be able to locate the resource or may find the wrong one. Image shows the dog attempting to locate the fish, but he finds a cat instead.

You can secure endpoints using HTTPS only, input validation, rate-limiting, and one-way password hashing. Image shows the dog wearing an HTTPS collar.

REST vs GraphQL

GraphQL is a query language that can request specific data from a server, represent as a fishing rod. REST is an architectural style that is popular in REST APIs used across the web. Here it is represented as a fishing net.

REST APIs return data from a server in a way that returns the whole data set. This is represented as a fishing net catching a school of fish all together.

GraphQL is represented a single fish being caught on a hook, the same way GraphQL can return specific data. GraphQL does this thanks to schema definition language, and only requiring a single endpoint.

Advantages of REST. It is easy to use, flexible and scalable, and client and server independent. Advantages of GraphQL. It is fast, requires less bandwidth, and can be tailored to your data needs.

You should choose between GraphQL and REST based on your applications needs. Diagram shows the fishing net being used to sell fish at a market, and the single fish from the hook being fed to a cat, representing how data requirements differ.

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Difference between SDK and API

What's the difference between an SDK and an API? RapidAPI Comic cover.

SDK stands for software development kit. They contain a set of ready-to-use tools that allow developers to build applications for specific platforms. You can think about them as a toolbox shown in the image.

APIs are another 'tool' often included in SDKs. Image shows an open toolkit with the word API inside.

SDKs can contain several components that facilitate the application building process. Most will always contain a compiler, debugger, and APIs but may also contain documentation, testing tools, libraries, etc. 
Image shows puzzle pieces labeled as components that end up creating an application.

There are many SDKs available online such as Android, Facebook, and Java. Image shows three toolkits labeled as each one.

Introduction to GraphQL

An introduction to GraphQL RapidAPI Comic cover.

What is GraphQL? GraphQL is a query language that lets clients request only the exact data they require from a server.

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