Let's use this core trac issue for discussion:

https://core.trac.wordpress.org/ticket/60375

Let's formalize a protocol for two Playgrounds (and, later on, WordPresses) to exchange updates with each other.

Technically, this would involve:

• Using disjoint numerical space for autoincrement IDs to avoid conflicts
• A network transport
• A local transport (for apps using "Headless Playground" as a storage backend)
• Bits from the Transfer Protocol:
  • Replacing host-specific data like site URLs with placeholders
  • Providing “export” and “import” extension points for plugins
  • Restoring the site URL and other host specific data from placeholders
  • Communicate any issues like missing PHP extensions, mismatched PHP version etc
• A hosting connector to publish the changes
• ...more, for sure

Related issues

• WordPress for Docs #1544
• PHP: Stream downloading/processing of remote resources #1028
• Full-site Export / Import Format #1563
• Blueprints: Streaming zip/unzip for browser and server #482
• Bump auto-increment fields in database to a high and recognizable starting offset. #771
• Synchronize two Playground instances #727

Open questions

• How to reconcile two plugins writing serialized data to the same database record?

Related reading

• InstaWP two-way sync

cc @dmsnell