Customer engagement platforms help teams coordinate relevant interactions across email, SMS, push, in-app messages, chat, and other channels. The best choice depends on the experience you need to deliver, the customer data you have, and which teams will operate the platform.
The short version: Knock is best for engineering, product, and lifecycle teams that need programmable transactional and lifecycle messaging with in-app experiences. Customer.io, HubSpot, and ActiveCampaign fit teams that want lifecycle automation tied to product data or a CRM. Braze, OneSignal, Iterable, MoEngage, and CleverTap fit mobile-first or cross-channel programs. Klaviyo is purpose-built for ecommerce, while Salesforce Marketing Cloud fits teams that run on the Salesforce ecosystem.
In this post, we compare 11 customer engagement platforms by best fit, key strengths, and typical buyer.
What is a customer engagement platform?
A customer engagement platform (CEP) is software for coordinating customer interactions across channels and stages of the customer journey. Depending on the product, a CEP may combine audience management, message orchestration, personalization, experimentation, analytics, customer support, or delivery infrastructure.
A CEP is not the same as a CRM or customer data platform (CDP). A CRM manages customer records and sales or service relationships, and a CDP collects and unifies customer data. A CEP activates customer data through messages and experiences. Some vendors combine more than one of these functions.
How to evaluate customer engagement platforms
We evaluated each platform against the following criteria. Use them to build your own shortlist.
- Use case fit. Decide whether your priority is transactional notifications, lifecycle marketing, mobile engagement, ecommerce, customer support, or a combination.
- Channels and orchestration. Confirm that the platform supports the channels you use and can coordinate branching, delays, batching, throttling, preferences, and event-based triggers.
- Data model and integrations. Evaluate how the platform receives events, models users and accounts, builds audiences, and works with your warehouse, CDP, CRM, and delivery providers.
- Developer experience. Review APIs, SDKs, documentation, versioning, environments, observability, and testing support.
- Team workflow. Make sure engineering, product, marketing, growth, and support teams have the controls they need without creating unsafe handoffs.
- Analytics and governance. Look for delivery logs, engagement tracking, experimentation, access controls, and ways to export data to your analytics stack.
- Total cost of ownership. Compare implementation, message or contact volume, add-ons, support, and ongoing operating effort, in addition to the advertised license price.
Quick comparison
| Platform | Best for | Key strength | Typical buyer |
|---|---|---|---|
| Knock | Transactional, lifecycle, and in-app engagement | Developer-first orchestration plus no-code operating tools | Product-led SaaS and digital products |
| Customer.io | Data-driven lifecycle campaigns | Flexible event data and visual journeys | Growth-stage digital products |
| HubSpot | CRM-centered marketing, sales, and service | Unified suite and approachable operations | SMB and mid-market teams |
| ActiveCampaign | Email-led automation for growing businesses | Email automation and CRM features | SMB and mid-market businesses |
| Braze | Mobile-first cross-channel engagement | Real-time mobile and lifecycle orchestration | Mid-market and enterprise B2C |
| OneSignal | Accessible push-led multichannel messaging | Push, in-app, email, and SMS with quick setup | Startups to mid-market apps |
| Iterable | Enterprise cross-channel orchestration | Flexible journeys across email, mobile, and in-app | Enterprise B2C marketing teams |
| MoEngage | Insights-led mobile engagement | Mobile analytics, segmentation, and orchestration | App-centric B2C businesses |
| Klaviyo | Ecommerce email and SMS | Commerce data, segmentation, and prebuilt flows | SMB and mid-market ecommerce |
| CleverTap | High-volume mobile engagement and analytics | Behavioral analytics with mobile messaging | Large consumer apps |
| Salesforce Marketing Cloud | Engagement inside the Salesforce ecosystem | CRM-connected journeys and enterprise breadth | Large Salesforce customers |
The best customer engagement platforms
1. Knock
Knock is a customer engagement platform for building and operating transactional, lifecycle, and promotional messaging across email, SMS, push, in-app, chat, and webhooks. It gives engineering teams APIs, SDKs, environments, and versioned resources while giving product and lifecycle teams visual tools to launch and improve customer journeys.
Best for: Engineering, product, and lifecycle teams that want one programmable platform for transactional notifications, cross-channel journeys, broadcasts, and in-app experiences.
Key capabilities
- Workflows orchestrate event-driven, scheduled, and recurring journeys with branches, delays, batching, throttling, fetches, preference checks, and cross-channel routing.
- Broadcasts send one-time announcements to audiences across supported channels without requiring a new product event for every campaign.
- Dynamic audiences target users from live customer attributes, update in real time, and work across workflows, broadcasts, and guides.
- In-app guides deliver banners, modals, cards, paywalls, and tooltips through prebuilt components or a product's own component system.
- Preferences and multi-tenancy support user- and tenant-level controls for complex B2B products.
- Analytics and observability help teams inspect message delivery and engagement and send data to their observability, analytics, or warehouse tools.
- The Knock MCP server, Knock CLI, and agent plugins for Claude, ChatGPT, Cursor, and Grok Bot give AI agents purpose-built ways to build, inspect, and manage messaging resources.
Strengths
- Combines developer control with visual tools for product, lifecycle, and growth teams.
- Covers transactional and lifecycle messaging as well as one-time broadcasts and in-app product experiences.
- Includes production-ready in-app components while supporting bring-your-own UI.
- Supports advanced notification patterns such as batching, throttling, preferences, and per-tenant experiences.
Considerations
Knock becomes part of a product's messaging architecture, so teams should plan an initial engineering integration and define ownership across engineering and customer-facing teams.
Bottom line: Knock is a strong fit when customer engagement is part of the product experience, not standalone marketing campaigns, and multiple teams need to operate on shared messaging infrastructure. See Knock pricing for current plans.
2. Customer.io
Customer.io is a lifecycle messaging platform for behavior-triggered journeys across email, push, in-app, SMS, WhatsApp, Slack, and webhooks. It uses customer, event, and account data to trigger automations and one-time broadcasts.
Best for: Growth-stage product and marketing teams that want data-driven lifecycle campaigns and are comfortable partnering with engineering on implementation.
Key strengths: Flexible event data, visual journeys, Liquid personalization, broadcasts, transactional messaging, and APIs suited to digital products.
Considerations: Evaluate in-app UI requirements, analytics depth, governance, and complex transactional patterns against your roadmap.
3. HubSpot
HubSpot combines marketing, sales, service, content, data, and revenue tools around its Smart CRM. Its engagement capabilities fit teams that want customer-facing functions to share CRM context.
Best for: SMB and mid-market teams that want CRM-centered marketing, sales, and service without assembling many separate tools.
Key strengths: Connected CRM context, a broad suite, workflow automation, educational resources, and a large integration marketplace.
Considerations: Advanced mobile, in-app, or product-triggered orchestration may require additional tooling. Compare the exact hubs and editions needed rather than evaluating the entry product alone.
4. ActiveCampaign
ActiveCampaign combines email marketing, cross-channel automation, and CRM features for growing businesses.
Best for: SMB and mid-market teams whose engagement strategy is led by email automation and sales or lifecycle workflows.
Key strengths: Automation, email tooling, segmentation, CRM integrations, and a broad app ecosystem.
Considerations: Teams that need sophisticated mobile, in-app, or high-scale transactional orchestration should compare specialist platforms.
5. Braze
Braze is a customer engagement platform centered on real-time, cross-channel messaging for consumer brands. Its Canvas journey builder coordinates email, mobile push, SMS, in-app messages, web, WhatsApp, and other channels.
Best for: Mobile-first brands and enterprise B2C teams with dedicated lifecycle or marketing operations resources.
Key strengths: Real-time audience activation, mature mobile channels, and visual cross-channel journey orchestration.
Considerations: Enterprise implementations can require significant data integration, operating discipline, and specialist resources.
6. OneSignal
OneSignal offers push notifications, in-app messaging, email, SMS, and journey automation for web and mobile products. Journeys can combine channels with event-based entry, waits, branching, exit rules, and testing.
Best for: Startups and mid-market app teams that want to launch push and in-app messaging and expand into additional channels.
Key strengths: Web and mobile push, SDK adoption, segmentation, and multichannel journeys in an accessible package.
Considerations: Organizations with complex enterprise data models, governance, or customized orchestration should validate those requirements during evaluation.
7. Iterable
Iterable is an enterprise cross-channel marketing platform for email, SMS, push, in-app messaging, web push, WhatsApp, RCS, and coordinated customer journeys.
Best for: Enterprise B2C marketing organizations that need flexible cross-channel lifecycle orchestration.
Key strengths: Visual journeys, experimentation, personalization, and broad support for email and mobile engagement.
Considerations: Confirm implementation effort, data requirements, reporting needs, and the operating model required for your team.
8. MoEngage
MoEngage combines customer analytics, real-time segmentation, and orchestration across push, in-app, email, SMS, WhatsApp, web, and other channels.
Best for: App-centric consumer businesses that want mobile engagement paired with behavioral insights.
Key strengths: Mobile analytics, segmentation, visual journey orchestration, and optimization tools for consumer lifecycle teams.
Considerations: Validate regional support, integrations, implementation resources, and channel requirements for your markets.
9. Klaviyo
Klaviyo is a B2C CRM and marketing automation platform known for ecommerce email and SMS. It connects commerce, behavioral, and engagement data to dynamic segments, flows, forms, and revenue reporting.
Best for: Small and mid-market ecommerce brands that want commerce-focused email, SMS, and cross-channel automation.
Key strengths: Ecommerce integrations, purchase-based segmentation, prebuilt lifecycle flows, and revenue attribution.
Considerations: Teams building product-led SaaS, complex B2B account models, or customized in-app engagement should compare platforms designed for those use cases.
10. CleverTap
CleverTap combines mobile engagement, real-time segmentation, experimentation, product analytics, and cross-channel orchestration for consumer apps.
Best for: Large mobile apps and digital businesses that want behavioral analytics and customer engagement in the same platform.
Key strengths: Mobile-first messaging, live segments, cohort analysis, experimentation, and lifecycle optimization.
Considerations: Teams should validate channel providers, integrations, governance, and developer-experience requirements alongside its mobile strengths.
11. Salesforce Marketing Cloud
Salesforce Marketing Cloud is Salesforce's enterprise marketing suite. Marketing Cloud Engagement uses Journey Builder for cross-channel journeys, while Marketing Cloud Next uses Flow and Data 360 for real-time triggers and orchestration.
Best for: Large organizations standardized on Salesforce CRM that want engagement workflows connected to the same ecosystem.
Key strengths: Enterprise breadth, CRM integration, partner ecosystem, and support for complex organizational structures.
Considerations: The product family is broad and its packaging changes over time. Buyers should map the exact Salesforce products, implementation partners, and data architecture required for their use case.
How to choose the right platform
Start with the customer moments you need to support, then work backward to the platform requirements. Map your transactional notifications, lifecycle journeys, one-time announcements, in-app experiences, and service conversations. For each one, document the trigger, audience, channel, timing, owner, data dependency, preference rule, and success signal.
Shortlist platforms that cover the most important moments without forcing your team into a mismatched operating model. A marketing-led team may prioritize visual journey building and campaign analytics. A product-led company may care more about APIs, source control, multi-tenancy, observability, preferences, and UI components. A support-led organization may prioritize conversation history, routing, and agent productivity.
Then run a proof of concept with a real journey and real data. Test implementation, authoring, approvals, failure handling, analytics, and day-two maintenance in addition to the ideal demo path.
Frequently asked questions
What is a customer engagement platform?
A customer engagement platform is software that helps a business coordinate customer interactions across channels such as email, SMS, push, in-app messages, chat, and webhooks. Depending on the platform, it may also include audience management, personalization, experimentation, analytics, or customer support.
What is the best customer engagement platform?
There is no single best platform for every company. Knock is a strong choice for product-led teams that need transactional, lifecycle, broadcast, and in-app engagement on shared developer-first infrastructure. Customer.io and ActiveCampaign fit many lifecycle and email automation programs. Braze, Iterable, MoEngage, and CleverTap suit many mobile or enterprise B2C programs, while Klaviyo is purpose-built for ecommerce.
What is the difference between a CEP, CRM, and CDP?
A CRM manages customer records and sales or service relationships. A CDP collects and unifies customer data from multiple sources. A CEP uses customer data to coordinate messages and experiences across channels. Some products combine two or all three categories, so evaluate capabilities rather than category labels.
Which customer engagement platform is best for transactional email?
For transactional email, prioritize reliable event-triggered workflows, logs, retries, templates, preferences, testing, and developer tooling. Knock handles transactional notifications and coordinates email with in-app, push, SMS, chat, and webhook steps in the same workflow. Email delivery providers can also serve as the delivery layer beneath an orchestration platform.
What features should I look for in a customer engagement platform?
Look for the channels you need, event-based orchestration, audience and data flexibility, personalization, preferences, experimentation, delivery logs, engagement analytics, APIs and SDKs, role-based controls, and integrations with your CRM, warehouse, CDP, and delivery providers. Weight those features according to your primary use case.
How much does a customer engagement platform cost?
Pricing varies by vendor and may depend on contacts, active users, messages, channels, seats, data volume, or add-ons. Compare current vendor pricing pages and ask for a total-cost model that includes implementation, support, overages, and ongoing operating effort. For Knock, see the current pricing page.
Increase customer engagement with Knock
The right customer engagement platform depends on who owns the customer experience and where engagement happens. When engagement lives inside your product, you need infrastructure that engineering can build on and that product, lifecycle, and growth teams can operate.
Knock gives your teams one platform for transactional notifications, lifecycle journeys, broadcasts, and in-app experiences. If you'd like to try it, you can sign up for a free account or chat with our team.