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APIs · head to head

Ably vs KeystoneJS

Ably logo

Ably

APIs

Realtime data delivery platform for pub/sub messaging at scale

From
Free
Rated
-
Full reviewWebsite
KeystoneJS logo

KeystoneJS

APIs

Powerful Node.js headless CMS framework and API platform

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Ably standard and Pro plans layer usage-based charges for messages, connection minutes, and data transfer on top of the base subscription, adding cost complexity.; KeystoneJS database support is limited to PostgreSQL, MySQL and SQLite
  • They diverge on capability: Ably covers Pub/sub messaging, KeystoneJS covers REST API.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Ably and KeystoneJS actually diverge.

Attributes where Ably and KeystoneJS differ
AttributeAblyKeystoneJS
Pricing modelfreemiumopen-source
Platformsweb, ios, android, apiNode.js, Self-hosted
FoundedUnknown2016

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (APIs).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Ably

  • Pub/sub messaging
  • Presence
  • Message persistence
  • Multi-protocol support
  • Encryption
  • Datadog integration

Only in KeystoneJS

  • REST API
  • GraphQL API
  • Admin interface
  • Node.js
  • Next.js
  • React
  • Databases
  • Node.js support

What people use each for

The jobs each tool is most often brought in to do.

Ably

  • Building realtime chat or collaborative appsnot KeystoneJS
  • Delivering live data feeds like stock prices or sports scoresnot KeystoneJS
  • Broadcasting notifications to many concurrent clientsnot KeystoneJS
  • Running mission-critical realtime infrastructure with high uptime SLAsnot KeystoneJS

KeystoneJS

  • Headless CMS implementationnot Ably
  • Content management systemsnot Ably
  • Customizable API-driven applicationsnot Ably

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Ably

  • Standard and Pro plans layer usage-based charges for messages, connection minutes, and data transfer on top of the base subscription, adding cost complexity.
  • The jump from Standard ($29/month) to Pro ($399/month) is steep for teams needing more than 10k connections but not full Pro capacity.
  • 24/7 mission-critical support and 99.999% uptime SLAs are reserved for the custom-priced Enterprise tier.

KeystoneJS

  • Database support is limited to PostgreSQL, MySQL and SQLite
  • Keystone 5 is a separate legacy product documented on a different site and is not covered by the Keystone 6 docs
  • Upgrading requires following a dedicated Migrate to 8.0.0 guide, so major versions are not drop-in
  • Free support is a community Slack; enterprise-grade consulting and support is a separate paid engagement with Thinkmill and no published price

Pricing, plan by plan

Ably

Free
  • FreeFree
    • 200 concurrent connections
    • 500 messages/second
    • 6M messages/month
  • Standard$29/month
    • 10k concurrent channels
    • 10k concurrent connections
    • 2.5k messages/second
  • Pro$399/month
    • 50k concurrent channels
    • 50k concurrent connections
    • 10k messages/second

KeystoneJS

Free
  • Open SourceFree
    • Full KeystoneJS
    • Community support

Which should you pick?

Choose Ably if

  • You need pub/sub messaging.
  • You want to start without paying.
  • You work on web, ios, android, api.
  • You also want presence.
Ably review

Choose KeystoneJS if

  • You need rest api.
  • You want to start without paying.
  • You work on Node.js, Self-hosted.
  • You also want graphql api.
KeystoneJS review

Questions people ask

Is Ably or KeystoneJS better?
Neither clearly leads. Ably starts at Free and KeystoneJS at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Ably or KeystoneJS?
Ably starts at Free and KeystoneJS at Free.
Does Ably or KeystoneJS run on more platforms?
Ably runs on web, ios, android, api. KeystoneJS runs on Node.js, Self-hosted.
Can I use Ably for free?
Both have a free tier, so you can try either at no cost before committing.
What is Ably best used for?
Ably is most often used for building realtime chat or collaborative apps, delivering live data feeds like stock prices or sports scores, broadcasting notifications to many concurrent clients, running mission-critical realtime infrastructure with high uptime slas. Of those, building realtime chat or collaborative apps and delivering live data feeds like stock prices or sports scores are not what KeystoneJS is typically brought in for.
What can Ably do that KeystoneJS cannot?
Ably covers Pub/sub messaging, Presence, Message persistence, Multi-protocol support. KeystoneJS covers REST API, GraphQL API, Admin interface, Node.js.

Answered from the vendors’ own pages

Ably: What does Ably cost?

Ably offers a free plan with 200 concurrent connections, a Standard plan at $29/month plus usage, a Pro plan at $399/month plus usage, and custom Enterprise pricing with unlimited channels and connections.

Source
KeystoneJS: Is KeystoneJS free?

Yes, KeystoneJS is free and open source with no licensing fees. Core platform has no lock-in and is contributed to by 250+ developers.

Source
Ably: Is there a free plan, and what are its limits?

Yes, the free plan includes 200 concurrent connections, 500 messages per second, and 6 million messages per month with community and best-effort email support.

Source
KeystoneJS: What are hosting costs for KeystoneJS?

KeystoneJS is self-hosted and deployment-agnostic. Hosting costs depend on your chosen deployment platform (Vercel, AWS, Heroku, etc.) and infrastructure, not KeystoneJS itself.

Source
Ably: How is usage metered?

Beyond plan limits, Ably charges usage-based rates of $2.50 per million messages, $1.00 per million connection minutes, $1.00 per million channel minutes, and $0.25 per GiB of data transfer, with volume discounts available.

Source
KeystoneJS: Does KeystoneJS offer paid support?

Enterprise support with tailored options is available from Thinkmill, the company behind KeystoneJS. Pricing details available upon request.

Source
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