This is Part 4 of Vantage Point's Headless 360 series. Part 1, "Salesforce Headless 360: Architecture and Readiness Guide," maps the four architecture layers and defines where MCP and HXL each fit. This post is the practitioner deep dive on the experience layer itself: HXL, the Mosaic framework, and the hands-on Playground. Other parts of the series cover Headless 360 for developers, Headless 360 for admins, headless commerce, and headless identity.
With Dreamforce weeks away, the Headless 360 conversation tends to focus on APIs and MCP servers — the plumbing. But plumbing alone does not put a useful experience in front of a user. That is the job of the Headless Experience Layer (HXL) and Mosaic, Salesforce's declarative framework for building a widget once and rendering it natively in Agentforce, Slack, ChatGPT, Claude, or any MCP host. For product owners, developers, and innovation leads, this is the piece that turns "our agents can call Salesforce" into "our users get a real interface wherever they already work." This guide covers what HXL and Mosaic actually are, how the Playground works, and what to try before Dreamforce.
The Headless Experience Layer (HXL) is Salesforce's control plane for how agent-driven experiences appear across your business: you define business logic and UI intent once inside Salesforce, and HXL renders it natively on any surface — Slack, ChatGPT, Claude, Agentforce, mobile, or a custom portal. Mosaic is the declarative JSON format you use to build those surface-agnostic widgets, and the HXL Playground is the free, no-setup environment where you can learn the format and preview widgets across surfaces live.
Salesforce's Trailhead module Speak the Language of Headless 360 defines HXL plainly: it "separates your business logic from the screen it appears on. Instead of building a separate app for every surface, you define your intent once inside Salesforce and HXL renders it natively wherever your users already work — Slack, WhatsApp, a custom portal, or anywhere else. One definition. Any surface."
Salesforce's Headless Experience Layer product page frames it as the control plane for how AI shows up across your business — separating what an agent should do from how that experience is delivered. It is built on custom Lightning types and a multichannel UI framework, so the same agent response adapts natively across Lightning Experience, mobile, Slack, Teams, ChatGPT, and any first- or third-party surface.
The problem HXL solves is one every multi-channel team recognizes: without it, you rewrite security, data, and UI logic for every channel — an internal tool here, a customer portal there, Slack and ChatGPT on the roadmap. Salesforce calls this the context dilution and logic fragmentation problem. HXL's answer is fourfold:
Mosaic is the declarative JSON format that HXL widgets are written in. The HXL Playground introduces three terms that map neatly onto MVC concepts you already know:
| Mosaic term | What it is | MVC analogy |
|---|---|---|
| Component | A building-block primitive — the smallest renderable unit (text, button, container, table) | — |
| Widget | A surface-agnostic UI composition built from components — like a page that works everywhere | View |
| Type / Action | The data shape behind a widget, and the things a user can do with it | Model / Controller |
A minimal widget is a few lines of JSON. Here is the Playground's "Hello World" example, which renders a styled text component:
{
"definition": "tile/text",
"attributes": {
"text": "Hello, Widget!",
"variant": "h1"
}
}
The definition property specifies which component to render; attributes configures its content and styling. From there, the Playground's curriculum builds up to layouts, data binding, iteration, and conditional rendering — still all declarative JSON, with no platform-specific code. Because the widget describes structure, data, and actions rather than pixels, each host surface renders it with its own native look and feel.
Part 1 of this series defines the distinction; here is the practitioner's version. MCP and HXL answer different questions:
| MCP (Model Context Protocol) | HXL (Headless Experience Layer) | |
|---|---|---|
| Question it answers | How does an agent call Salesforce? | How does the experience appear to the user? |
| What it carries | Tool calls, data, and actions | UI intent — widgets, layout, and interaction |
| Who defines it | Salesforce-hosted and custom MCP servers expose tools | You define widgets once in Mosaic |
| Where it shows up | Any MCP-compatible client (Claude, ChatGPT, Cursor, Agentforce) | Any surface that renders HXL — including those same MCP hosts |
In practice they compose: an agent on an MCP host calls Salesforce tools through MCP, and HXL delivers the response as a native, interactive widget on that surface. MCP is the pipe; HXL is the presentation. You can adopt MCP without HXL (pure tool-calling), but the "deploy everywhere" story — a governed, branded, interactive experience on every surface — requires the experience layer.
The HXL Playground is the fastest way to build real intuition, and it requires no setup. Three areas matter:
Salesforce's admin team has already published a guided tour — Tour HXL Playground | Kate Clicks Through It (July 2026) — which makes an important point for non-developers: if you can build flows and shape data models as an admin, HXL unlocks that same expertise for systems and agents beyond the platform. You stay in control of how agents surface data and how information displays on any platform your users call home.
The Playground previews four surfaces today — Agentforce, Slack, ChatGPT, and Claude — and the design target is broader: any MCP host, plus first-party surfaces like Lightning Experience and mobile, collaboration hubs like Teams, and messaging channels like WhatsApp or a custom portal. The strategic point is not the specific list; it is that the list can grow without you rebuilding anything. When the next surface matters to your users, a widget you defined once renders there natively.
That changes the economics of experience design. Instead of sequencing channels ("portal this year, Slack next year"), you decide which workflows deserve an interface, build them once under Salesforce governance, and let surface choice become a configuration decision rather than a development project.
Salesforce has been telling this story consistently since the Headless 360 announcement ("No Browser Required"). Three public artifacts are worth your time before Dreamforce:
The pattern to copy: one workflow, one surface, governed logic — then let the experience layer carry it everywhere else.
Vantage Point helps teams turn HXL's promise into a governed pilot: selecting the first workflow and surface, designing Mosaic widget patterns that respect your permission model, and connecting the experience layer to your broader Salesforce implementation and advisory and system integration and data migration strategy. Senior consultants only — no junior handoffs; the experts you meet are the experts who deliver.
HXL is Salesforce's experience layer for Headless 360: it separates your business logic from the screen it appears on, so you define an experience once inside Salesforce and it renders natively on any surface — Agentforce, Slack, ChatGPT, Claude, mobile, or a custom portal.
Mosaic is the declarative JSON format used to build HXL widgets. You compose surface-agnostic widgets from components (text, buttons, containers, tables), with Types defining the data and Actions defining what users can do — analogous to Model, View, and Controller.
MCP is the protocol that lets AI agents call Salesforce tools and data; HXL is the layer that renders the resulting experience as a native UI on each surface. MCP is the pipe, HXL is the presentation — they compose, but solve different problems.
HXL is the newest layer of Headless 360 and is currently in beta, with availability expanding. Check Part 1 of this series for the availability and licensing picture, and confirm component-level status before planning a production timeline.
The HXL Playground previews widgets across Agentforce, Slack, ChatGPT, and Claude, and the design target is any MCP host plus first- and third-party surfaces — Lightning Experience, mobile, Teams, WhatsApp, and custom portals.
Not necessarily. Widgets are declarative JSON, and Salesforce's admin team positions HXL as a way for admins to extend flow and data-model expertise to new surfaces. Developers add the most value on data binding, actions, and governed deployment patterns.
HXL experiences inherit Salesforce's native permissions and sharing models automatically, and guardrails are centrally managed — so a widget surfaces only what the running user is allowed to see, on every surface.
Ready to build once and deploy everywhere? Whether you are prototyping your first Mosaic widget, evaluating HXL against your channel roadmap, or preparing your Dreamforce agenda, Vantage Point's senior consultants can help you move from playground to production. Contact Vantage Point to schedule a Headless 360 readiness session, or explore our Salesforce services to see how we support teams end to end.
Vantage Point is a boutique CRM consulting firm helping businesses transform with Salesforce, HubSpot, and AI — 150+ clients, 400+ engagements, and a 4.71/5 average engagement rating. Learn more at vantagepoint.io.