404 on http://localhost/wp-json/wp/v2/posts in wordpress using REST API V2

http://localhost/?rest_route=/wp/v2/posts should works. Refer https://developer.wordpress.org/rest-api/using-the-rest-api/discovery/ for details.

First you need to enable the apache rewrite module with the following command:

 sudo a2enmod rewrite

then we must edit the configuration file of our virtual host

sudo nano /etc/apache2/sites-available/your_config.conf

and add in the following directive

<Directory /var/www/your_root_directory>
                Options Indexes FollowSymLinks MultiViews
                AllowOverride All
                Order allow,deny
                allow from all
</Directory>

note: change your directory path

now our file should look like this

<VirtualHost *:80>
    <Directory /var/www/your_root_directory>

        . . .

    </Directory>
    ServerName midomain.com
    . . .
</VirtualHost>

Now Restart the service of apache

sudo service apache2 restart

create a .htacces file in your root directory of your web site

sudo nano /var/www/your_root_directory/.htaccess

and finally add into .htaccess

RewriteEngine on
RewriteRule ^wp-json/wp/v2/posts$ ?rest_route=/wp/v2/posts [NC]

Add index.php after your root link:

http://localhost/wordpress/index.php/wp-json/wp/v2/posts

That worked for me.

This may help who face same problem after choosing pretty links in WP:

https://github.com/WP-API/WP-API/issues/497#issuecomment-420405995

I will put this answer here to stay even original is deleted.

From: ecker00

While this is old, people still seems to find this thread when looking for issues with 404 on wp-json, judging by all the emojis on the previous post. Thought I would share my solution, as my Nginx config was:

location / {
    try_files $uri $uri/ /index.php?$args =404;
}

Removing =404 at the end solves it, but if you don't want wordpress to handle 404 pages it's better to add this in bellow:

location /wp-json/ { # Resolves WP Gutenberg 404 issue
    try_files $uri $uri/ /index.php;
}