Softwr

APIs · head to head

Ably vs Clerk

Ably logo

Ably

APIs

Realtime data delivery platform for pub/sub messaging at scale

From
Free
Rated
-
Full reviewWebsite
Clerk logo

Clerk

Cybersecurity

Drop-in user authentication and management for developers

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.; Clerk pricing scales with monthly retained users, which can grow expensive quickly for consumer apps with large user bases.
  • They diverge on capability: Ably covers Pub/sub messaging, Clerk covers Prebuilt UI components.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Ably and Clerk actually diverge.

Attributes where Ably and Clerk differ
AttributeAblyClerk
CategoryAPIsCybersecurity

Identical on both: starting price (Free), pricing model (freemium), free tier (Yes), platforms (web, ios, android, api), user rating (Not yet rated).

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 Clerk

  • Prebuilt UI components
  • Organization management
  • Multi-factor authentication
  • Social sign-on
  • Billing
  • Enterprise connections

What people use each for

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

Ably

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

Clerk

  • Adding sign-in and user profiles to a web or mobile app quicklynot Ably
  • B2B SaaS apps needing organizations and role-based accessnot Ably
  • Startups wanting prebuilt UI instead of building auth in-housenot Ably
  • Apps needing MFA and fraud detection out of the boxnot 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.

Clerk

  • Pricing scales with monthly retained users, which can grow expensive quickly for consumer apps with large user bases.
  • Enterprise SSO connections beyond the first are billed as add-ons, adding cost for larger organizations.
  • The Business tier's extra dashboard seats cost $20/month each, which adds up for larger teams.
  • Enterprise-tier features like the 99.99% uptime SLA require annual contracts rather than flexible monthly billing.

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

Clerk

Free
  • HobbyFree
    • 50,000 MRU limit per app
    • Up to 3 dashboard seats
    • Unlimited applications
  • Pro$25/month
    • 50,000 MRUs included, $0.02/MRU overage
    • Up to 3 dashboard seats
    • 1 Enterprise Connection included
  • Business$300/month
    • 50,000 MRUs included with volume pricing
    • 10 dashboard seats included
    • SOC2 report and priority support
  • Enterprise$undefined/month
    • Custom pricing, annual billing
    • 99.99% uptime SLA
    • HIPAA available, dedicated Slack channel

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 Clerk if

  • You need prebuilt ui components.
  • You want to start without paying.
  • You work on web, ios, android, api.
  • You also want organization management.
Clerk review

Questions people ask

Is Ably or Clerk better?
Neither clearly leads. Ably starts at Free and Clerk at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Ably or Clerk?
Ably starts at Free and Clerk at Free.
Does Ably or Clerk run on more platforms?
Both run on web, ios, android, api, so platform support will not decide this one for you.
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 Clerk is typically brought in for.
What can Ably do that Clerk cannot?
Ably covers Pub/sub messaging, Presence, Message persistence, Multi-protocol support. Clerk covers Prebuilt UI components, Organization management, Multi-factor authentication, Social sign-on.

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
Clerk: What does Clerk cost?

Clerk's Hobby plan is free with a 50,000 MRU limit; Pro is $25/month ($20/month billed annually), Business is $300/month ($250 annually), and Enterprise uses custom annual pricing.

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
Clerk: Is there a free plan and what are its limits?

Yes, the Hobby plan is free with a 50,000 monthly retained user (MRU) limit per app, up to 3 dashboard seats, and unlimited applications, with no credit card required.

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
Clerk: How is usage metered?

Clerk meters by monthly retained users (MRUs) — users who return to the app at least a day after signing up — with overage billed at $0.02 per MRU beyond the included 50,000 on paid plans.

Source
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