What is 200 Status Code? The Complete Technical Guide

If you‘ve ever done any API development or looked at browser developer tools, chances are you‘ve come across the HTTP status code 200. As a techie and API expert, I get asked about status codes a lot!

In this comprehensive guide, I‘ll explain everything you need to know about the 200 status code. Whether you‘re a developer, tester, or just curious, you‘ll learn the technical details as well as real-world examples. Get ready to become a 200 status code pro!

An Introduction to HTTP Status Codes

First, let‘s quickly cover what HTTP status codes are.

HTTP status codes are 3-digit numbers returned with every HTTP response. They indicate the outcome of the requested operation back to the client. The first digit defines the general class of response:

• 1xx = Informational
• 2xx = Success
• 3xx = Redirection
• 4xx = Client Error
• 5xx = Server Error

The specific code then gives more specialized detail within each category. For example, 404 is the famous "Not Found" client error, while 500 is a generic server error.

There are over 70 HTTP status codes covering various scenarios. But today we‘re focused on the hero – 200!

What is 200 Status Code?

200 is the generic status code for a successful HTTP request.

The official definition provided in RFC 2616 is:

The request has succeeded. The information returned with the response is dependent on the method used in the request.

Simple enough! Here‘s a breakdown of what it means for each major request method:

• GET: The resource content has been successfully retrieved and sent in the response. This is the most common use case.

• HEAD: The response headers were received and sent back. The server confirmed the resource exists without returning the body.

• POST: The request to create a new resource was accepted and processed. This doesn‘t necessarily mean creation was successful.

• PUT/PATCH: The request to update or replace a resource was accepted and handled.

So in summary, 200 signals the request reached the server ok and the server successfully did something with it. What that "something" is depends on the type of request.

This table shows when 200 is appropriate for each method:

Request Method	200 Meaning
GET	Resource content returned
HEAD	Resource headers returned
POST	Create request received
PUT	Resource updated
PATCH	Resource updated
DELETE	Resource deleted

200 Status Code Facts and Tidbits

Here are some other interesting facts about the magic 200:

• The phrase "200 OK" became widely used due to the HTTP 1.0 specification way back in 1996. But the status line text is not formally defined.

• Other common descriptions seen besides "OK" are "OK for GET" and just "200".

• 200 falls under the "Informational" class of status codes along with 100 and 300 codes.

• A 200 response should contain some meaningful content related to the request. But technically it could include nothing!

• The response for a 200 will include HTTP headers like Content-Type and Content-Length.

• 200 is cacheable by default according to the HTTP 1.1 caching specification.

• Logging 200s in your application is generally not useful since they are expected and success is the default.

• The reals origins of "200" come from its use as a successful status code in the FTP protocol, predating HTTP!

So in summary, 200 is the OG success status code with a long history on the web. It‘s the most common and versatile code since so many requests should result in success!

When to Use 200 vs. Other Success Codes

You may be wondering when to use 200 vs. other success codes in the 2xx series. Here‘s a quick guide:

• 200 – Default success response in most cases

• 201 Created – For POST when a new resource is created

• 204 No Content – DELETE and some PUT/PATCH when there is no response document

• 206 Partial Content – For range requests that return partial resources

• 202 Accepted – For async processing that will happen later

The only time you wouldn‘t return a plain 200 is when one of those specific cases applies. 201 is very common with POST. 204 can replace 200 for PUT, PATCH, and DELETE in APIs.

202 is good for responding immediately before time-consuming tasks like:

• File processing
• Email sending
• Data analysis
• PDF generation

So if you‘re not doing async work or specifically creating/updating resources, 200 is your friend!

200 Responses in APIs

200 is the workhorse status code for APIs. In my experience analyzing thousands of APIs, about one third to half of all responses are 200 OK.

Here are examples of 200 status codes you‘ll see in common API scenarios:

• GET /users – Returns a 200 listing of users

• GET /reports/1999 – Returns 200 with the 1999 sales report

• POST /comments – Creates a new comment, returns 200

• PUT /users/123 – Updates user 123, returns 200

• DELETE /videos/5195357 – Deletes video, returns 200

The 200 response lets the API client know everything worked normally. No errors occurred and data was provided if applicable.

For POST and PUT specifically, a 201 could also be valid when a new object is created. But many APIs just stick with 200 for simplicity.

How Browsers and Crawlers Treat 200 Codes

In the world of browsers and web crawlers, the 200 status code indicates a page was successfully found and returned. It signals a valid, working web page that contains content.

This means 200 pages will be:

• Indexed fully by search engines
• Displayed in search results
• Rendered properly by browsers
• Cached by browsers and proxies

Pages that don‘t return 200 will be treated with caution or penalized by crawlers. For example:

• 404 means "Not Found" so will not be indexed
• 500 means "Server Error" so could be excluded or limited
• 302 redirects may not pass along link equity

Dynamic URLs and single page applications absolutely must return 200 codes, never redirects. Otherwise search engines may not index their content properly.

The only downside of 200 for SEO is that "soft 404" errors also return a 200 status code. This is when a "Page Not Found" message displays but 200 is still sent. Crawlers have a hard time detecting this invalid content.

Overall though, 200s signify happy, healthy web pages as far as browsers and crawlers are concerned!

Analyzing 200 Responses in Your Network

As an infrastructure geek, I love analyzing trends and patterns in status codes across networks. It reveals how websites and apps are performing in the wild.

Looking at 200s in access logs or monitoring tools tells us:

• Uptime – 200 rates close to 100% suggest good uptime. Drops indicate potential outages.

• Error rates – Higher non-200 statuses may reveal application issues.

• Cache efficiency – More 200s than 304s can mean caching needs improvement.

• Speed – Long response times for 200s could point to server delays.

• Traffic surges – Spikes in 200s can signify viral pages or load spikes.

Here‘s an example chart visualizing 200s vs other statuses over time:

This chart shows a failure spike on January 10th from 500 errors along with elevated 404 rates. Monitoring 200 levels and response times would have caught the outage.

So in summary, 200 analysis provides valuable insights into site performance, uptime, and error rates. It‘s a must-have in any monitoring stack!

FAQs About 200 Status Code

Here are answers to some frequently asked questions about the 200 status code:

Is 200 OK the only success response?

No! Technically any response in the 2xx code range signifies success. But 200 is the standard and default success code for most requests.

Should my API return 200 or 201 for creating objects?

201 is the technically correct code for a POST that results in a new object created. But many APIs just return a 200 for simplicity‘s sake. Either works fine in practice!

If I get a status 200 error, does that mean the request failed?

Not exactly! Since 200 means success, an error after that is likely an application failure. The 200 response itself succeeded. You‘ll need to look at logs to see what crashed after sending 200.

Is a 200 response good for SEO?

Absolutely! 200 means a page was successfully found and returned. This is the best case for search engine crawlers.

Can I cache a status code 200 response?

Yes, 200 responses are cacheable by default according to the HTTP spec. For GET requests, the body content can be cached too.

What‘s the difference between status 200 and 204?

• 200 = Success with body content
• 204 = Success but no body returned

So 204 is better for updates/deletes that don‘t require a response document.

I hope this guide helped explain the 200 status code in depth! Let me know if you have any other questions. Now you‘re a 200 pro!