Wordpress - Jetpack Running Locally

As of JetPack 2.2.1 there is now a local development/debug mode. http://jetpack.me/2013/03/28/jetpack-dev-mode-release/

use:

define ('JETPACK_DEV_DEBUG', true);

in your wp-config and you should have access to any modules that don't require a connection to function.

Update, since around v3.3 another local development trigger was added via filter instead of define.

Latest is now here: http://jetpack.me/support/development-mode/

Development mode automatically gets enabled if you don’t have a period in your site’s hostname, i.e. localhost. If you use a different URL, such as mycooltestsite.local or something, then you will need to define the JETPACK_DEV_DEBUG constant.

You can also enable Jetpack’s development mode through a plugin, thanks to the jetpack_development_mode filter:

add_filter( 'jetpack_development_mode', '__return_true' );

As of Jetpack v3.9 there is also now a staging mode filter that forces a site to be recongized as a staging site rather than production: https://developer.jetpack.com/hooks/jetpack_is_staging_site/

add_filter( 'jetpack_is_staging_site', '__return_true' );

The method in the link provided by @TracyRotton seems not to be working since Jetpack 2.0 and WordPress 3.4.2.

Even replicating all database fields, it doesn't act as connected.

---

As the OP question is about syncing a development and a production environments, maybe it is not possible.

I haven't tested in-depth which modules work and which not, but Jetpack can be tricked into believing it is connected making the following modification in the file /plugins/jetpack/jetpack.php.

Inside the class Jetpack_Data, modify the very first function get_access_token like:

class Jetpack_Data {    
    function get_access_token( $user_id = false ) {
        return 'USER_TOKENS-VALUE-FOUND-INSIDE-THE-OPTION-JETPACK_OPTIONS'; // <---trick
        if ( $user_id ) {
            if ( !$tokens = Jetpack::get_option( 'user_tokens' ) ) {
                return false;
            }

Or simply put a return true; instead of the user_tokens that we can copy from inside the option jetpack_options.

_{PS: the first version of this answer used another trick. Here, it is a one-line modification that catches all, in theory...}

It is possible to trick JetPack by copying the database field values from an activated install into your local install.

On an install (remote) with JetPack connected search the wp_options table for option_name fields beginning with jetpack_, such as:

• jetpack_activated
• jetpack_options
• jetpack_nonce_{random_string}
• jetpack_active_modules

Copy these fields and values into your local installs database.

For more detail on this process see: http://www.ravendevelopers.com/node/57