Ably vs Pusher vs Pubnub review
Ably vs Pusher vs Pubnub review
Ably wins for production realtime in 2026 if you need guaranteed message ordering, exactly-once delivery, and global edge presence with strong SLAs. Pusher wins for the fastest "ship a feature today" path: cheap, simple Channels API, dead-simple SDKs. PubNub wins when you need turnkey extras (presence, push, functions, signals) bundled into one platform and don't want to assemble them yourself.
Most teams overspend on realtime because they pick the platform that markets best, not the one matched to their message pattern. This post breaks down the three vendors on the dimensions that actually decide infra cost: presence semantics, channel limits, message rate ceilings, edge geography, durability, replay, and the real price at 1M, 10M, and 100M monthly messages.
What each platform actually is
Ably is a realtime data delivery network founded in 2015, headquartered in London, with a strong engineering reputation for protocol-level correctness. Their pitch is the "four pillars" of realtime: ordering, delivery, integrity, performance. Ably publishes formal definitions of each and backs them with a 99.999% uptime SLA on enterprise plans.
Pusher Channels (acquired by MessageBird, now Bird) is the OG of "websockets as a service," launched in 2011. It is the simplest API of the three: subscribe to a channel, receive events, done. Pusher Beams (push notifications) is a separate product. Most posts comparing the three really mean Channels.
PubNub launched in 2010 and has the broadest product surface of the three: pub/sub, presence, message persistence, functions (edge code), push notifications, mobile-push, app context (key-value), and access manager. It markets as a "platform" rather than a transport.
The honest tl;dr by use case
| Use case | Pick |
|---|---|
| Live cursors, low-stakes presence | Pusher |
| In-app notifications, activity feeds | Pusher or Ably |
| Multiplayer collaborative editing | Ably |
| Financial dashboards, trading UIs | Ably |
| Live sports / betting tickers | Ably |
| Chat with built-in moderation, push, history | PubNub |
| IoT telemetry at scale | PubNub or Ably |
| Replacing a Socket.IO server you regret | Pusher (Channels Lite) |
| You need exactly-once + ordering guarantees | Ably (only one that promises it) |
For most early-stage SaaS adding realtime to a dashboard, Pusher remains the right call. Our earlier Pusher review goes deeper on why it still ships features fastest in 2026.
Presence and state: the biggest difference
Presence (knowing who is connected to a channel) is where the three platforms diverge most.
- Pusher has presence channels. Each member has a
user_idand arbitraryuser_info(JSON). You pay per-presence-member-per-month on higher plans. State is in-memory only; if a process crashes, members re-sync on reconnect, and you can see brief duplicate joins. - Ably has presence with
enter,update,leave, and a server-sidepresence-setyou can fetch at any time. Ably persists presence state inside the cluster, so reconnects rehydrate cleanly. It also exposespresence.history()so you can audit who was online when. - PubNub has presence and "App Context" (formerly Objects), giving you channel members, channel metadata, and user metadata as a queryable store. Presence emits
join,leave,timeout,state-change, andintervalevents. Heartbeat timeouts are configurable down to 20s.
The practical takeaway: if presence drives billing or compliance (paid seats in a doc, regulated chat rooms), use Ably or PubNub. If presence is cosmetic (avatars on a doc), Pusher is fine.
Channel limits and message rate ceilings
This is where you get surprised on your second invoice.
| Limit | Pusher Channels | Ably | PubNub |
|---|---|---|---|
| Max channels per app | Unlimited (soft) | Unlimited | Unlimited |
| Max subscribers per channel | 100 (Free) to unlimited (Enterprise) | 200 default, 1M with shared subs | Unlimited |
| Max message size | 10 KB | 64 KB default, 1 MB max | 32 KB default, configurable to 32 KB |
| Max messages per second per channel | 100 default | 100 default, raisable | 100 default |
| Presence members per channel | 100 (Startup) to 10k+ (Enterprise) | 200 default, raisable | Unlimited (paid) |
| Durability / replay window | 24h on Channels Pro+ | 24h to 72h (Reach plan: persisted) | 7 days (Message Persistence add-on) |
The most common gotcha: Pusher's 10 KB message size. If you are syncing CRDT deltas, JSON payloads with rich text, or anything with embedded base64, you outgrow Pusher faster than your message count suggests. Ably's 64 KB default and 1 MB ceiling is the most forgiving.
Geographic edge points
Latency-sensitive apps care about edge geography.
- Ably runs in 8+ AWS regions plus edge POPs in 635+ cities via Akamai/Cloudflare partnerships. Their routing algorithm picks the lowest-latency region per client.
- Pusher runs in 6 named clusters (us-east-1, us-east-2, us-west-2, eu, ap-southeast-1, ap-southeast-2, ap-northeast-1, sa-east-1, eu-west). You pick a cluster at app creation; clients connect to that single region. Cross-region replication is not automatic.
- PubNub runs a global anycast network of 15+ POPs with automatic geo-routing. Their messaging is that any client connects to the nearest POP and the network handles internal replication.
For a US-only product, all three feel the same. For global products (anything with European GDPR users plus US plus Asia), Pusher's single-cluster model is a real constraint: a Tokyo user on a us-east-1 Pusher app gets ~140ms round trips that Ably and PubNub deliver in ~30ms.
Durability and replay
What happens if a subscriber disconnects for 30 seconds and reconnects?
- Pusher by default: nothing. The subscriber missed those messages. With Pusher Channels' message buffering (Pro plan and up), reconnecting clients get the last 24h replayed from the missed point.
- Ably: messages are persisted for 2 minutes by default (rewind window). With the Reach plan or message persistence, you get 24h to 72h replay, plus the
history()API to query any range up to your retention. - PubNub: with Message Persistence add-on, you get 1 day to unlimited retention (priced per add-on). The
fetchMessagesAPI pulls up to 100 messages per channel, with paging.
If your product is collaborative editing or anything where missed messages mean lost data, Ably's rewind model is the cleanest. PubNub's persistence is the deepest if you want messages as a system of record.
SDK ergonomics
Subjective, but here is how each feels in practice.
Pusher Channels SDK is the smallest API surface. Three calls and you are subscribed:
const pusher = new Pusher(KEY, { cluster: 'eu' })
const channel = pusher.subscribe('orders')
channel.bind('order.created', (data) => console.log(data))
Pusher's docs are short because there is not much to learn. This is the platform's biggest strength and biggest weakness. It is a transport, not a platform.
Ably SDK is more verbose because it exposes more semantics: connection state machine, channel attach/detach, presence, history, encryption, push, and Spaces (their collaborative-edit primitives). The TypeScript types are excellent. Connection recovery is automatic and configurable.
const ably = new Ably.Realtime({ key: KEY })
const channel = ably.channels.get('orders')
await channel.subscribe('order.created', (msg) => console.log(msg.data))
await channel.presence.enter({ user: 'bhavya' })
PubNub SDK feels like the oldest of the three because it is. The API uses a publishKey/subscribeKey pair and a listener-based model that can feel boilerplate-heavy. The React Native and Unity SDKs are strong; the modern TypeScript surface less so.
const pubnub = new PubNub({ publishKey, subscribeKey, uuid: userId })
pubnub.addListener({ message: (m) => console.log(m.message) })
pubnub.subscribe({ channels: ['orders'] })
For an experienced TypeScript team, Ably feels best. For shipping in an afternoon, Pusher wins. For mobile-first or game-engine apps, PubNub's SDK breadth is unmatched.
Free tier comparison
| Free tier | Pusher Channels | Ably | PubNub |
|---|---|---|---|
| Connections | 100 concurrent | 200 concurrent | 200 daily active devices |
| Messages | 200k/day | 6M/month | 1M transactions/month |
| Presence members | 100 | included in connections | included |
| Apps | 1 | unlimited | 1 keyset |
| Cluster choice | 1 cluster | global | global |
| Card required to start | No | No | No |
| Support | Community | Community | Community |
For a hackathon or weekend project, all three free tiers are workable. PubNub's "transactions" billing makes their free tier harder to reason about because every API call (publish, subscribe message, presence event, history fetch) counts as a transaction.
Pricing at 1M, 10M, and 100M messages per month
Approximate list pricing as of mid-2026. Real enterprise contracts negotiate down 20-40%.
| Monthly volume | Pusher Channels | Ably | PubNub |
|---|---|---|---|
| 1M messages, 500 concurrent | ~$49/mo (Startup) | ~$29/mo (paid plan) | ~$49/mo (Starter) |
| 10M messages, 2k concurrent | ~$299/mo (Growth) | ~$185/mo | ~$299/mo |
| 100M messages, 10k concurrent | ~$1,499/mo (Business+) | ~$960/mo | ~$1,200-1,800/mo (depends on add-ons) |
| 1B messages, 50k concurrent | Enterprise quote | ~$5-8k/mo | ~$8-15k/mo |
Ably consistently lands as the cheapest of the three at 10M+ messages because they bill on a single "message" unit rather than splitting transactions, presence events, and connections into separate meters. PubNub's add-on model (persistence, presence, app context, push, functions all separate) makes the bill less predictable.
Pusher's pricing is the most predictable because the product is the simplest. You know what you owe before you ship.
The strongest argument for each
Pick Ably when:
- You need ordered, exactly-once delivery with formal guarantees
- You are building global (sub-50ms latency in Tokyo, London, and Sao Paulo)
- You want one bill that does not surprise you at 100M messages
- You need Spaces (live cursors, comments, locks) without building it yourself
Pick Pusher Channels when:
- You are adding realtime to an existing dashboard this week
- Your team is small and you want the smallest API surface
- Single-region latency is acceptable (US-only or EU-only product)
- You want predictable billing and a generous free tier
Pick PubNub when:
- You are building chat, gaming, or IoT and want batteries-included
- You need Access Manager for fine-grained channel auth
- You want Functions (edge code on messages) without standing up Cloudflare Workers
- Your team is comfortable with the older SDK ergonomics in exchange for product depth
Where teams get stuck
Most realtime-migration headaches we see at Cadence are not platform choice. They are reconnect logic, auth-token rotation, and message ordering bugs that show up only under packet loss. All three platforms handle the happy path; the difference is what happens at 2am when AWS loses a zone.
This is also where the build-vs-buy debate comes back. Self-hosting Socket.IO or Centrifugo looks cheap until you hit your first multi-region outage. The right framing is usually: use Pusher or Ably until you are spending $4k/month on realtime, then revisit self-hosting with a senior engineer who has done it before. Our best deployment platforms for startups guide covers the infra side of that decision.
For founders evaluating realtime tools as part of a broader stack review, our Resend transactional email review and best AI agent platforms for developers round out the modern AI-native infra picture.
What to do next
If you are choosing for the first time:
- List your three biggest channels (busiest, presence-heavy, largest payload).
- Estimate messages per second on each.
- Plug into each pricing calculator. Add 3x for headroom.
- Pick the cheapest of Ably and Pusher unless you specifically need PubNub's add-ons.
If you are migrating from a vendor you regret, the realistic effort is 1 to 2 weeks for a small product, 3 to 6 weeks for anything with custom presence logic. Every engineer on Cadence is AI-native by default, vetted on Cursor, Claude Code, and Copilot fluency before they unlock bookings, so realtime migrations land closer to the 1-week end of that range.
A senior engineer at $1,500/week can usually deliver an Ably or Pusher migration end to end in a single booking, including reconnect tests, presence state, and replay window validation. If you are still scoping, you can audit your tooling honestly before committing to a vendor swap.
FAQ
Is Ably more expensive than Pusher?
Below 1M messages a month, Pusher and Ably are within $20/mo of each other and the free tiers are similar. Above 10M messages, Ably is usually 30-40% cheaper because they bill a single message unit rather than splitting connections, presence, and messages into separate meters. Pusher gets relatively expensive at scale.
Can I self-host any of these?
No. All three are managed services. The closest open-source equivalents are Centrifugo (Pusher-like API), Soketi (Pusher-protocol compatible), and Socket.IO with Redis adapter. Self-hosting saves money above $4k/month spend but adds on-call burden and multi-region complexity.
Which one has the best React or Next.js support?
All three publish first-class JS SDKs. Ably has the strongest typed-TypeScript surface and a dedicated React hook library (@ably/react). PubNub has React hooks too. Pusher's pusher-js is plain JS with TypeScript types added; community React wrappers are good but not first-party.
What about Socket.IO?
Socket.IO is a library, not a hosted service. You run it yourself on your own servers (Node, with Redis or Postgres for multi-instance pub/sub). It is the right call when you have a strong infra team and want full control. Pusher, Ably, and PubNub exist for teams that want to skip that operational work.
Does PubNub still make sense in 2026?
Yes, but narrower than before. PubNub wins for chat platforms, gaming, and IoT where their bundled extras (App Context, Access Manager, Functions, push) save you stitching together separate vendors. For generic websockets or pub/sub on a SaaS dashboard, Ably or Pusher will be cheaper and simpler.
How does this compare to Supabase Realtime or Convex?
Supabase Realtime is Postgres-driven (you get realtime updates on database row changes). Convex is a full backend that includes realtime. Both are excellent if you are already in their ecosystem. None replace Ably, Pusher, or PubNub for cases where you need pure pub/sub without a database round trip per message.