Platform Comparison

CloudSignal vs Ably
Open Protocol vs Proprietary

Both platforms deliver real-time messaging. The difference is whether your infrastructure depends on an open standard or a single vendor's protocol. Here's an honest look at both.

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Feature-by-Feature Comparison

An honest side-by-side. We note where Ably has a clear advantage.

Feature
CloudSignal
Ably
Protocol
MQTT is a 30-year-old open standard — no lock-in
MQTT (ISO/IEC 20922 open standard)
Proprietary Ably protocol
Pricing model
Ably bills can scale unpredictably under load
Flat monthly tiers — no per-message or per-connection fees
Per-message + per-connection + per-channel charges
Free tier
$0 free tier, unlimited time
Free tier with message limits
Security model
Broker-level enforcement means no way to bypass security in app code
ACL rules enforced at the broker level, identity-bound topics
Authorization in application middleware (capability tokens)
Offline support
Offline delivery is built into the MQTT protocol, not bolted on
Native MQTT QoS 0/1/2, retained messages, persistent sessions
Message queuing via add-on, no native protocol-level QoS
AI integration
Both platforms offer AI streaming; Ably has more mature product breadth
AI Transport for Vercel AI SDK — streaming over MQTT with offline resume
Ably AI Transport product
Scale & uptime
Ably has a proven track record at hyperscale
99.9% uptime SLA
100% uptime over 7 years, 30B+ connections/month, 6.5ms latency
Vendor lock-in
None — MQTT is open; run your own broker any time
Proprietary protocol — migrating requires client rewrites
Product breadth
Ably offers more off-the-shelf collaboration products
MQTT pub/sub, AI Transport, real-time analytics
Pub/Sub, Chat, AI Transport, LiveObjects, Spaces
Enterprise features
Ably is the better choice for large enterprise procurement requirements today
In roadmap (SSO, dedicated infra)
SSO, SOC 2, dedicated clusters, enterprise SLAs

Why the Differences Matter

Not all feature gaps are equal. Here's why CloudSignal's approach has lasting engineering value.

Open Protocol, Zero Lock-In

MQTT is a 30-year-old ISO/IEC standard backed by thousands of implementations. If you ever need to migrate off CloudSignal, your MQTT client code runs unchanged on any other broker — open source or managed. That's a guarantee no proprietary protocol can match.

Security at the Broker Layer

ACL rules in CloudSignal live inside the MQTT broker itself, not in your application code. Every publish and subscribe is validated against topic-pattern rules before a byte leaves the network. You can't accidentally bypass it with a middleware bug.

Predictable, Flat Pricing

Per-message billing is a trap — spikes in traffic, reconnections, or retained messages all add to the bill. CloudSignal charges flat monthly tiers so you can model your costs exactly, even at high message throughput.

Offline-First by Protocol

MQTT QoS levels 1 and 2 guarantee at-least-once and exactly-once delivery. Retained messages let new subscribers catch up on state immediately. Persistent sessions resume mid-stream after a network drop. These are protocol primitives, not product features you enable with a toggle.

How to Decide

The right choice depends on your use case, scale, and how much the open-protocol guarantee matters to you.

Choose CloudSignal when…

  • You're building AI-native apps and need streaming responses that survive network drops
  • You need broker-enforced security, not just middleware checks
  • You want to avoid vendor lock-in and keep the option to self-host
  • You have predictable or high-volume messaging and want flat pricing
  • You're already using MQTT (IoT, embedded, industrial) and want a managed host
  • You're a startup or small team that needs a generous free tier to prototype

Choose Ably when…

  • You need proven hyperscale — billions of messages per month with 100% uptime history
  • You need Ably-specific products: Chat, Spaces, or LiveObjects
  • You have existing Ably infrastructure and a migration would be costly
  • You require enterprise procurement features today: SSO, SOC 2 Type II, dedicated clusters
  • You need sub-10ms latency globally at massive concurrency

Pricing You Can Model in Advance

No per-message, per-connection, or per-channel line items. Pick a tier and know your monthly cost regardless of traffic spikes.

Free
$0
forever
  • Up to 3 MQTT users
  • 1 organization
  • Community support
Pro
$29
per month
  • Up to 50 MQTT users
  • 5 organizations
  • Email support
  • AI Transport
Scale
$79
per month
  • Up to 200 MQTT users
  • Unlimited organizations
  • Priority support
  • AI Transport
Open Protocol. Flat Pricing. Real-Time.

Ready to Try CloudSignal?

Start on the free tier in minutes. No credit card required. Full MQTT support with broker-enforced security from day one.

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