How to Develop an API (Query Class )? Provide some ideas

For example, you can directly call a self-written interface on your website, how to write such an interface, and hope to give you some ideas, for example, this type of interface is used to query historical snapshots of a website. Are these tools self-written API interfaces? I have found a lot of APIs that do not have ready-made interfaces... Query Interfaces. For example, I can directly call the interfaces I have written on my website. I hope to give me some ideas on how to write these interfaces,

For example, if you want to query historical snapshots of a website, are these Apis written by yourself?

There are no ready-made interfaces found, and there is no idea to write it on your own.

For example:

Http://seo.chinaz.com/

This interface is used to query the server information of a website.

Do you know what it means? I don't know how to start. Please give me some advice. Please, I'm in a hurry.

Reply content:

For example, you can directly call your own interface on your own website. How do you write this interface? I hope to give you some ideas,

For example, if you want to query historical snapshots of a website, are these Apis written by yourself?

There are no ready-made interfaces found, and there is no idea to write it on your own.

For example:

Http://seo.chinaz.com/

This interface is used to query the server information of a website.

Do you know what it means? I don't know how to start. Please give me some advice. Please, I'm in a hurry.

Returns a json string in ajax mode.