I am creating a post to list all cloud-hosted alternatives to Firestore. All of these databases are scalable and serverless technologies.

1. Cloud Firestore

NoSQL Database built on Firebase platform

• Amazing support for many different libraries
• Incredible Default Realtime Support with Robust Caching
• Wonderful Robust Security Rules for Backend Validation written in CEL (Common Expression Langauge)
• Very Limited Querying
• No support for any type of joins
• Must handle all types of counts manually
• Vendor Lockin, can't use outside of Firestore
• Firestore Functions can do a lot in background
• See here for my in-depth problems with Firestore (love/hate)
• Price: Pricing based on usage

2. Dgraph Cloud

Graph Database using GraphQL known to be faster than Neo4j based on Badger.

• Extremely Fast and Powerful
• Has realtime support through graphql websockets.
• Very Limited Backend Validation Security (Hopefully they are working on this), but can hack this with Custom Lambda Mutations (a lot more work) written in GraphQL Queries
• No Nested Filters (same thing as filtering JOINS), should have this by end of the year, can hack with custom DQL queries
• Has Data Studio like Cloud Firestore
• Can Edit almost everything in Cloud Studio
• Use my easy-dgraph js library for easily creating graphql queries
• Best used with URQL for Caching
• Will have storage usage in the future like Firebase
• Must use external Auth Controls like Firebase Auth or Auth0
• Price: $39.99 a month, or dedicated based on usage ($199)

3. Supabase.io

PostgresSQL using a JS Library with an online easy-to-use system.

• JS Library makes any kind of queries easy to create, especially complex joins and filters
• Uses Postgres's RLS (Row Level Security) policies for very robust backend validation
• Has current storage bucket capabilities like Firebase
• Has built-in Auth controls
• Price: $25 a month, or dedicated based on usage

4. Hasura Cloud

GraphQL postgreSQL database

• RLS for security
• Needs Auth0 or Firebase for authentication
• NHost.io built on top of this
• Price: $99 a month standard to custom

5. Nhost.io

PostGreSQL with GraphQL built on Hasura

• Adds storage and RBAC to Hasura.

6. MongoDb Atlas

GraphQL connection to feature rich noSQL.

• Has Robust Join Capabilities for a denormalized database, but can be slow if not indexed
• Many Languages Support, Functions, Triggers
• Streams for Realtime Support via Websockets
• Has a GraphQL api
• JSON Schema Validation and built in RBAC
• Price: $57 a month dedicated instance

7. Fauna

GraphQL connection for custom relational noSQL.

• Realtime available using streams, limited
• Built in ABAC, Custom FQL Rules for Robust Security Validation
• Vendor Lock-in, can't view under-the-hood
• Price: $22.5 a month, $135, $450, depending on needs

8. Neo4j Aura

GraphDb, basic graphQL, uses Cypher Language for everything else

• Cypher includes RBAC and Robust Query Validation
• Realtime support with external instance of Kafka (from my understanding), not built-in
• Limited Documentation
• GraphQL does not work out-of-the-box and needs a middlware server
• Price: $65 a month to custom

9. Amazon Neptune

GraphDb, gremlin and SPARQL (latest technology!)

• AWS (IAM) for ABAC Security
• Lambda Functions (Java, Javascript, and other langauges) - Field Validation as well
• Gremlin Websocket for Realtime
• Limited Documentation
• Easy access to all Amazon Services
• Price: Custom pricing, probably starts at $450 a month

10. MariaDB Cloud / SkyDB

A Fork of MySQL management

• Built-in User Management
• MYSQL Validation Data Rules
• Realtime Data Streams with Kafka (not built-in to my understanding)
• Storage Options
• Price: Custom Pricing, pay as you go, maybe $700 starting?

11. TigerGraph Cloud

GraphDB Restful Endpoint

• Restful Endpoint
• RBAC Built-in
• GSQL Query Langauge for Security Field Validation
• Kafka for real time streaming
• Price: Pay as you go, dedicated, could get expensive, free version with credits

12. Nebula Graph

Chinese GraphDb with recent funding

• RBAC
• nGQL, openCypher for Security and Queries
• Kafka or Pulsar
• Nebula Graph Cloud in Beta

13. Redis Enterprise Cloud

Key Value Store that can be used as GraphDB

• Rest API
• RBAC
• Pubsub
• Price:Free Version, $7, and Flexible add GraphDB

14. HarperDB Cloud

SQL on JSON with Rest API

• NewSQL, Microservice Architecture
• Authentication Security (JWT and Roles), no field security that I can find
• Pubsub websockets
• Price: Free tier, per instance pricing

15. CockroachCloud

SQL on JSON

• NewSQL, allows complex querying
• Uses Changefeed to watch data
• Price:: No Free tier, by the hour

16. Couchbase Cloud

newSQL noSQL allowing relational data

• Spark Streaming, DStreams from DCP
• Price: per hour, custom pricing

17. InfiniteGraph

GraphDB, claims massive scalability

• Looks like GraphQL, probably websockets, documentation not available to free users?
• Price: - Free version , $100 50gb

18. SingleStore

• Elastic Cloud Database Relational SQL
• Could not find specifics, has streaming capabilities
• Price: - Credit system, free version gives $500 worth of credits

19. PlanetScale

Mysql compatible powered by Vitess

• In beta, could not find real time data information or client side integration
• Price: - low pricing for startups, cost per read / writes / storage

20. AstraDB

• Apache Cassandra NoSQL database
• DataStax Astra Streaming Technology
• Price: - has free tear, price per usage

Honorable Mentions (No Cloud Service or Enterprise Only Cloud)

• RethinkDB - JSON with joins, specialize in realtime data

• Appwrite.io - noSQL, storage, rest api

• GraphDB - Ontotext - RDF Db

• Stardog - RDF GraphDB, has custom cloud version, but no free version

• Apache Jena - RDF Triple Store

• Let me know pros and cons of any you have used.
• I will update the list if new features become available, so let me know.
• Post a comment if you know of another cloud-hosted product (must be serverless), and I will add it here as well.

J