Jetpack REST API

Instead of using the site URL, I’d recommend using the blog ID. This way you’ll avoid issues like the encoding of your site URL, especially when it includes a subdirectory:

https://public-api.wordpress.com/rest/v1.1/sites/102742951/posts/

Thanks for reply, where I can see my blog ID?

In this particular case, I used your blog ID in the link I pasted above.

To get another site’s blog ID, you can hit the /me/sites endpoint to get a list of all your connected sites and their blog IDs (among other things).
https://developer.wordpress.com/docs/api/1.1/get/me/sites/

You can also use the REST API console to make that query:
https://developer.wordpress.com/docs/api/console/

Yes I have seen that you have put my ID that is why I asked about ID, as I haven’t seen before. Thanks for information ??

One more question, can we use JetPack , when we use our own hosts, not the wordpress.com ?

Jetpack can only be installed and used on self-hosted WordPress sites, so yes, you’ll be able to use it if your site is not hosted on WordPress.com.