Regarding similar services? Kind of!

Ditto is both an embedded + cloud database + a mesh network, it's really 2 startups in 1.

A) If you're looking for just offline-first and data sync, there are some company's that have done this

1. Realm (MongoDB) - this is the company that my CoFounder and I came from.
2. Firebase (Google) - one of the biggest inspirations for me personally in data sync.
3. Supabase - a very popular growing open source Firebase alternative
4. All the GraphQL Backend-as-a-Service like Prisma, Hasura etc... These have offline caching with a lot of the GraphQL client libraries. I don't think actually have a database underneath the hood that you can query.

B) If you're looking for just mesh networks:

1. Build it yourself using Bluetooth Low Energy, Local Area Network, P2P Wi-Fi Direct, Apple Wireless Direct, Wi-Fi Aware APIs that come with most of your device frameworks. Build an advertising system, a common communication protocol, and add your identity security system. If you want multi-hop, you'll need to create a dynamic routing and presence system on top of it. After that design an API to send data around, respond to errors. If you want offline-first you should research CRDTs and try to build a database replication system using the mesh network.
2. You could use Apple's Multipeer Connectivity framework: this is iOS, MacOS devices only. No multi-hop here but you can build a system on top if it. One thing I've noticed is Apple's framework is a ruthless battery drainer. My phone gets very hot after a minute. It doesn't look like it uses Bluetooth Low Energy and it's advertising system seems to be extremely aggressive
3. Google has an abstraction called Nearby Messages that uses Bluetooth Low Energy. It isn't very stable but you could try to trick it to re-establish connections. After that you'll want to investigate how to pull off multi-hop. It's the same as step 1 and 2 https://developers.google.com/nearby/messages/overview
4. There was a company called Hypelabs that offered mesh network solution, but not the offline-first part. I'm not sure what's up with them
5. There's another company called Bridgefy https://bridgefy.me/ that built a chat app used in some of the Hong Kong protests
6. Open Garden also had Firechat in 2014

Ditto is a combination of both families of problems, it's basically creating 2 startups at the same time (mesh + distributed database):

* Offline first embedded mobile, web, IoT database called the small peer
* A large distributed database in the cloud called the Big Peer (this is new and what we need to operationalize for general avaiability pricing)
* A replication engine that uses our mesh network powered by Bluetooth Low Energy, Local Area Network, P2P Wi-Fi Direct, Apple Wireless Direct, Wi-Fi Aware

The problems that we have to tackle are so crazy; network optimizations, compression, multi-plexing, conflict resolution, scaling on the edge and cloud etc.... It's like the product that we're trying to create is teaching us as we build. For example one of the challenges that we have now with multi-hop is scaling performance. A large mesh of 1,000 devices may chatter so much just on the distributed routing table that it can cripple the replication of the actual data! So we are trying novel ways to dynamic route data by also incorporating special characteristics of CRDTs so that chatter is reduced and performance increases. Other major things we will improve are ways to prevent denial-of-service attacks even with trusted actors, decentralized access control of data, graph centrality theory etc...

Regarding use cases?

1. Well anything that's latency sensitive is perfect for us. Think controlling robots, syncing whiteboard pen strokes across devices, games, VR+AR.
2. Industry wise, any place where _any_ issue to internet connectivity means a loss of money, life, user experience: aviation, hospitals, point of sale, education, manufacturing, defense. A lot of our customers have internet 99.9% of the time but even that 0.1% is a nightmare that causes great issues.