Database hosting

AWS DynamoDB

Free tier: 25 GB of Storage, 25 Units of Write Capacity, 25 Units of Read Capacity
Pros: A NoSQL database with both document and key-value store models, replicated with high availability. The free tier is enough to handle up to 200M requests per month.
Limitations: One unit of read/write capacity handles one request per second (or two requests per second in the case of eventually consistent reads). Has both strongly consistent and eventually consistent reads.

Free tier: 1$/GB per month, $0.015$/100 “heavy” requests, $0.015/500 “light” requests, first $50 per month free
Pros: Full CouchDB hosting. Can host also static sites and javascript applications
Limitations: Account on shared multitenant instance
Exceeding the free tier: Credit card needed after first 30 days to charge exceeding usage

Free tier: 25$ per month for free, serverless databases. Up to 30 million reads, 4.5 million writes, 40GB in total.
Pros: Unlimited number of databases, Grafana-based health monitor, multiple providers (GCP, Azure, AWS)
Limitations: Does not support VPC peering, multi-region databases, materialized views, or logged batches

Free tier: Simple graph storage with unlimited repositories (public and private)
Pros: Repositories support SPARQL Query, SPARQL Update and SPARQL Graph protocol and query federation. There is also a simple Web interface for querying datasets, a Web API and a Command-line interface
Limitations: Invite Only.

Free tier: 20MB storage, 5 simultaneous connections
Pros: SQL web browser for simple database inspection, secure connection over SSL, full automatic backups
Limitations: No SLA no in-memory cache, shared server

Free tier: 100k read ops, 100k write ops, 500k compute ops, 100MB storage
Pros: Serverless with global replication and ACID transactions. Native GraphQL support, ABAC security model and support for relational, document, graph, and time-series patterns.
Limitations: No team management or preview sandbox on free tier.
Exceeding the free tier: Hard limits enforced on free tier. Subscription plans offer metered overages.

Free tier: 1GB storage, 10GB/month transfer, 100 simultaneous connections
Pros: really fast can be used for real time pub/sub, libraries for multiple platforms, designed to be used directly from frontend (with security rules), integrates with Firebase Authentication
Limitations: no backups, limited queries, complicated security rules (read the manual!)

Free tier: 1GB storage/day, 50K reads/day, 20K writes/day, 20K deletes/day
Pros: dashboard, clients available in multiple languages, fully managed (sharding and replication), ACID transactions
Limitations: complex requests needs specific indexes (read the manual)

Free tier: Writes: 5MB every 5 minutes, Tasks & Queries: 300MB every 5 minutes, Storage: 30 days of retention, Cardinality: Up to 10,000 series, Alerting: 2 alert checks and 2 notification rules, You can create up to: 5 dashboards, 5 tasks, 2 databases to store your time series data
Pros: purpose-built time series database, pre-built UI and dashboarding tools, background processing and monitoring agent

Free tier: Start with a free 3-node replica set and 512 MB of storage / Shared RAM.
Pros: Fast, secure, and highly available MongoDB service for any scale.

Free tier: 1GB memory per container, shared CPU, 1GB disk usage (10GB hard limit), 100GB outbound traffic (unlimited inbound). Read more
Pros: Allows hosting multiple databases (PostgreSQL, MySQL, Redis, MongoDB) and you can have your app and database on the same platform and run both of them for free. Also see for app hosting.
Limitations: 3 projects, 2 plugins per project, 2 environments per project, 3 live deploys per environment.

Free tier: 30MB, 30 connections
Pros: managed, possibility to choose cloud provider (AWS, Azure, GCE, IBM Softlayer) and availability zones

Free tier: 500Mb storage, 100 simultaneous connections
Pros: Open source, built in realtime capabilities and auth, 40+ extensions and pgbouncer preinstalled
Limitations: Paused after 1 week of inactivity
Exceeding the free tier: There are no overage charges. Team will reach out asking user to upgrade to a higher plan if limits are exceeded.