Knock vs Liveblocks
An independent, review-free comparison compiled by the SaaSTracker editorial team. Both products are profiled in full, and neither can pay for placement here.
Still shortlisting? Browse the best in Notification Infrastructure for every option we track, with award winners called out.
The short answer
Both sides assessedKnock compared with Liveblocks
Different problems wearing the same interface. Liveblocks generates inbox notifications out of comments, mentions, and document activity, meters only the custom notifications you trigger yourself, and charges $30 a month once you leave the free plan, but it sends no SMS, no mobile push, and no email of its own, handing you a webhook instead. Knock orchestrates arbitrary product events across many channels with workflows, delays, branching, and multi-tenancy. If notifications in your product mean somebody was mentioned in a document, Liveblocks does that far more cheaply and brings the commenting with it. If they mean an event in your backend has to find a person somewhere, Knock.
Liveblocks compared with Knock
Both put a notification feed in your product and neither sends the mail itself, but they start from opposite ends. Knock is an orchestration engine: workflows, cross-channel fallback, delays, per-tenant configuration, SMS and mobile push through your own providers, free to 10,000 messages and then $250 a month. Liveblocks is a collaboration platform whose inbox is generated by comments and mentions, with no SMS, no workflow branching, and Pro at $30. If your notifications are events flowing out of a backend across many channels, Knock. If they are people mentioning each other inside your product, Liveblocks does that job for a twentieth of the price and brings the commenting with it.
Choose Knock if
Product and engineering teams at SaaS companies who need real product notifications (in-app feed, digests, preference centers, per-tenant configuration) and want the workflow logic owned by a platform a PM can edit rather than by application code an engineer has to redeploy.
Choose Liveblocks if
Product teams adding comments, mentions, or multiplayer editing to a web application who need the notification tray, the read state, the per-user channel settings, and the email digest hook that come with that work, and who are building in React.
Side by side
16 attributes| Attribute | Knock | Liveblocks |
|---|---|---|
| Category | Notifications | Notifications |
| Starting price | $0 (Developer), then $250 per month (Starter) | $0 (Free), then $30 per month (Pro), or $25 per month billed annually |
| Pricing model | Usage-based on messages sent, with a separate meter for Guide active users and AI agent credits, plus a large free tier and a single published paid plan before enterprise contracts. | A credit balance per month shared across every meter (collaboration minutes, comments, custom notifications, and realtime storage), with a free plan, two published paid tiers, and pay-as-you-go rates once the credits are spent. |
| Free plan | Developer includes 10,000 messages a month, 500 Guide active users, 500 AI agent credits, unlimited workflows, unlimited channels, unlimited team members, batching, delays, broadcasts, multi-tenancy, and Google SSO. | Free includes 200 custom notifications a month, unlimited collaboration notifications, all six notification channels, notification settings, batching, pre-built components, 3,000 collaboration minutes, 200 comments, 3M realtime storage updates, 1 GB of realtime storage, 3 dashboard seats, and 10 simultaneous connections per room. |
| Free trial | No time-limited trial; the Developer plan is permanently free | No time-limited trial; the Free plan is permanent |
| Best for | Product and engineering teams at SaaS companies who need real product notifications (in-app feed, digests, preference centers, per-tenant configuration) and want the workflow logic owned by a platform a PM can edit rather than by application code an engineer has to redeploy. | Product teams adding comments, mentions, or multiplayer editing to a web application who need the notification tray, the read state, the per-user channel settings, and the email digest hook that come with that work, and who are building in React. |
| Setup time | A day to a first workflow in production for a competent backend engineer, and one to three sprints to migrate an existing homegrown notification service. The in-app feed component is typically the fastest visible win. | A day to a working inbox if you are already using Comments, since the notifications generate themselves and the tray is a component. Two to four weeks for a full build that adds collaborative editing, custom notification kinds, and an email digest service you write yourself. |
| Learning curve | Low for engineers, moderate for product people. The concepts (workflows, recipients, tenants, channels, preferences) are clean, but the mental model of moving decision logic out of application code into a workflow platform takes a team a couple of weeks to internalize. | Moderate. Rooms, projects, threads, inbox notifications, and notification settings are clean concepts, but the split between what Liveblocks stores and what your backend still owns takes a little while to internalise, and the credit model needs one careful read before anyone forecasts a bill. |
| Platforms | Web dashboard, REST API, CLI, React and JavaScript components, iOS, Android, React Native, and Flutter clients, MCP server | Web dashboard, REST API, React and React UI packages, JavaScript client, Node.js server library, Webhooks |
| Compliance | SOC 2, GDPR, CCPA, HIPAA with a BAA on Enterprise | SOC 2, GDPR, HIPAA with a business associate agreement (paid add-on) |
| Founded | 2021 | 2021 |
| Headquarters | New York, New York, United States | Fully remote; Liveblocks Inc. is registered in Wilmington, Delaware, United States |
| Ownership | Venture-backed | Venture-backed |
| Free tier volume | 10,000 messages per month | 200 custom notifications per month, collaboration notifications unlimited |
| First paid tier | $250 per month (Starter) | $30 per month, or $25 per month billed annually (Pro) |
| Self-hosting | Not offered; managed cloud only | Not offered for the hosted service; the sync engine and dev server are open source |
Strengths and limitations
Knock
Strengths
- Batching, digests, preference centers, and multi-tenancy are all first-class, and they are exactly the four things engineering teams build worst when they build them in-house.
- The free Developer tier is extraordinarily generous, including unlimited workflows, unlimited channels, unlimited team members, and multi-tenancy at $0.
- Bring-your-own-provider means you keep your sending reputation, your existing SendGrid or Twilio contracts, and your negotiated rates.
- Workflows as code with CLI, version control, CI validation, environments, and one-click rollback, which makes notification changes a normal part of the software lifecycle instead of a risk.
Limitations
- Completely unusable without engineering; there is no path where a marketer signs up and gets value, because nothing happens until code calls the API.
- The pricing cliff from $0 to $250 a month with no intermediate plan penalizes exactly the small companies the free tier attracted.
- Guides are metered separately on active users, so the in-product messaging feature has its own cost curve that is easy to miss when budgeting.
- You still pay for delivery separately, and you still own deliverability, list hygiene, and domain authentication yourself.
Liveblocks
Strengths
- The notification tray, read state, per-user channel settings, and batching arrive as part of shipping comments and mentions, which is the work most teams were dreading anyway.
- All six delivery channels, notification settings, batching, and the pre-built components are available on the free plan, which almost nothing else in this category does.
- Collaboration notifications are unmetered on every plan, so the highest-volume notification type in a collaborative product costs nothing.
- Pro at $30 a month, or $25 billed annually, is the cheapest paid entry in the category by a very large margin.
Limitations
- Liveblocks never sends the email. It fires a webhook with the unread list and you compose and deliver the message yourself, which is real work the rest of this category absorbs for you.
- No SMS, no voice, and no mobile push beyond web push, so anything reaching a phone outside a browser needs another tool.
- Pre-built components are React. A Vue, Angular, or Flutter team gets APIs and builds the tray, which is the same complaint people make about Knock.
- The credit model pools four unrelated meters into one balance, which makes forecasting harder than a flat message allowance and hides which feature is spending the money.
Pricing compared
Knock
Usage-based on messages sent, with a separate meter for Guide active users and AI agent credits, plus a large free tier and a single published paid plan before enterprise contracts.
- Developer$0
- Starter$250
- EnterpriseCustom
Knock is priced as infrastructure, and the honest comparison is not against Mailchimp but against the salary cost of the engineer who would otherwise own your notification service. On that basis the free tier is remarkable value and Starter at $250 is fair, since 50,000 messages with batching, preference centers, in-app feed, and multi-tenancy is a quarter of engineering work you no longer do. The weakness is the plan gap: a team sending 15,000 messages a month is paying $250 for capability it barely uses, and the separate Guides meter means the sticker price understates the cost of using the whole product. Add your own provider bills on top and Knock is never the cheapest line on the invoice, but it is usually the one that saves the most.
Liveblocks
A credit balance per month shared across every meter (collaboration minutes, comments, custom notifications, and realtime storage), with a free plan, two published paid tiers, and pay-as-you-go rates once the credits are spent.
- Free$0
- Pro$30
- TeamFrom $600
- EnterpriseCustom
Judged as notification infrastructure, Pro at $30 a month is the cheapest credible option in this category by an order of magnitude, and the free plan is genuinely usable because the channel list and batching are not withheld from it. The reason it is cheap is that the expensive part, composing and sending the email, stays with you, and the notifications that would otherwise be metered are the ones the collaboration products generate for nothing. The model breaks down in two places: the credit pool makes the bill hard to forecast if collaborative editing is heavy, and the step from $30 to $600 arrives sooner than the number suggests once a team needs SOC 2, more than three console seats, or more than ten people in one room. Buy it when collaboration is genuinely part of the product; it is poor value as a general notification router.
Editorial verdict on each
Knock
Category LeaderKnock is the right purchase when your notification problem is a product problem rather than a marketing problem. If people are complaining about email volume, if a preference center keeps slipping down the roadmap, if enterprise customers want Slack delivery, or if an engineer already owns a homegrown notification service they resent, this is the layer to buy and the free Developer tier is generous enough to prove it in a weekend. The reasons to walk away are equally clear: there is no marketing surface, nothing works without engineering, you still pay your own providers, and the leap from $0 to $250 a month with nothing in between is genuinely painful for a small team. For a five-person startup, Knock is the first thing to reach for only if you are shipping a product with an in-app notification feed. If your immediate need is onboarding emails and lifecycle campaigns, start with Customer.io, Bento, or Dittofeed and add Knock later when the product notifications become their own problem.
Read the full Knock profileLiveblocks
Liveblocks is the right purchase when the notifications your product needs are about people working on the same thing. Add Comments or a collaborative editor and the inbox, the unread state, the per-user channel settings, the batching, and the email digest hook arrive with it, the notifications those features generate are never metered, and the paid plan starts at $30 a month against $249 or $250 everywhere else in this category. Two things should send you elsewhere. If your notifications are billing alerts, order updates, and system warnings with no collaboration behind them, you are buying a sync engine to get a tray and Knock, Courier, or SuprSend will serve you better. And if the messages have to reach a phone by SMS or native push, Liveblocks does not go there at all. For a React product adding collaboration, it is the cheapest good answer in the category by a distance.
Read the full Liveblocks profileKnock profile last reviewed 2026-09-07; Liveblocks last reviewed 2026-09-13. Pricing is compiled from public sources and can change without notice. See our methodology.
The best in Notification Infrastructure
9 trackedNotification infrastructure platforms sit between an application and its delivery providers, turning one API call into orchestrated in-app, email, push, SMS, and chat notifications with batching, digests, preference centres, and per-tenant routing, so product teams stop rebuilding that logic in application code.
Batching, preference centres, and multi-tenancy are first-class rather than roadmap items, and workflows-as-code with environments and rollback makes a notification change a normal deploy.
$30 a month for 30,000 workflow runs, or nothing at all self-hosted, against a category whose next cheapest real plan is $110 and whose leader jumps from free to $250.
Founded in 2022 on roughly $1M, SuprSend shipped nine channels on the free tier, CLI environment promotion, an MCP server, and an Agent SDK while larger rivals were still writing about them.
The delivery planner turns cross-channel escalation into configuration: try in-app, fall back to email only if it goes unread, set as a rule rather than written as application code.
A visual designer that previews every channel on one canvas, and a bill that is $0.005 a send with no seats or channel fees, let a non-developer own the message end to end.
Frequently asked questions
6 questionsWhat is the difference between Knock and Liveblocks?
Different problems wearing the same interface. Liveblocks generates inbox notifications out of comments, mentions, and document activity, meters only the custom notifications you trigger yourself, and charges $30 a month once you leave the free plan, but it sends no SMS, no mobile push, and no email of its own, handing you a webhook instead. Knock orchestrates arbitrary product events across many channels with workflows, delays, branching, and multi-tenancy. If notifications in your product mean somebody was mentioned in a document, Liveblocks does that far more cheaply and brings the commenting with it. If they mean an event in your backend has to find a person somewhere, Knock.
Is Knock or Liveblocks cheaper?
Knock starts at $0 (Developer), then $250 per month (Starter). Liveblocks starts at $0 (Free), then $30 per month (Pro), or $25 per month billed annually. The billing models differ, so the entry price is rarely the whole cost. Knock pricing model: Usage-based on messages sent, with a separate meter for Guide active users and AI agent credits, plus a large free tier and a single published paid plan before enterprise contracts. Liveblocks pricing model: A credit balance per month shared across every meter (collaboration minutes, comments, custom notifications, and realtime storage), with a free plan, two published paid tiers, and pay-as-you-go rates once the credits are spent.
Does Knock or Liveblocks have a free plan?
Knock has a free plan. Developer includes 10,000 messages a month, 500 Guide active users, 500 AI agent credits, unlimited workflows, unlimited channels, unlimited team members, batching, delays, broadcasts, multi-tenancy, and Google SSO. Trial terms: No time-limited trial; the Developer plan is permanently free. Liveblocks has a free plan. Free includes 200 custom notifications a month, unlimited collaboration notifications, all six notification channels, notification settings, batching, pre-built components, 3,000 collaboration minutes, 200 comments, 3M realtime storage updates, 1 GB of realtime storage, 3 dashboard seats, and 10 simultaneous connections per room. Trial terms: No time-limited trial; the Free plan is permanent.
Who should choose Knock?
Product and engineering teams at SaaS companies who need real product notifications (in-app feed, digests, preference centers, per-tenant configuration) and want the workflow logic owned by a platform a PM can edit rather than by application code an engineer has to redeploy.
Who should choose Liveblocks?
Product teams adding comments, mentions, or multiplayer editing to a web application who need the notification tray, the read state, the per-user channel settings, and the email digest hook that come with that work, and who are building in React.
What are the best alternatives to Knock and Liveblocks?
SaaSTracker profiles 9 products in Notification Infrastructure. The Summer 2026 awards in the category went to Novu (Best Value), SuprSend (Momentum), MagicBell (Innovation). Every profile is compiled from primary sources, so a shortlist can be built from pricing, limitations, and fit rather than from star ratings.
