Apps Overview
Extend your workspace with integrations, custom UIs, and automations
Apps are how start.chat connects to the outside world and how you make your workspace your own. What makes apps here different from integrations in other chat platforms is how they’re created and how deeply they integrate.
What this section covers
Read the Apps docs when you want to build something that lives inside the workspace itself: an integration, a channel UI, a scheduled backend, or a tool that AI and flows can call.
You can write an app inline in a conversation — just start a code block with the
block tag. You can ask HUD to generate one for you. You can develop one
locally with your favorite editor using desktop sync. And once it exists, an app
can render UI inside your workspace, run scheduled backends in the cloud, store
structured data, expose actions that other apps and agents can call, and display
live indicators in the channel’s HUD bar.
Apps vs blocks
To make sense of the ecosystem, it helps to think of two categories.
Apps are integrations that connect your workspace to outside services. The
built-in GitHub app syncs issues and PRs, the Stripe app tracks payments, the
Linear app pulls in project data. Apps provide data, actions, and webhooks —
they bring the outside world in. Actions return structured data items
({ summary, data }) with well-defined fields like title, status, and url,
so the UI can automatically render results as tables, lists, and badges.
Blocks are inline UI you create right in chat. Start a code block with the
block tag and you get a sandboxed mini-app that renders inside your
conversation. Blocks are great for dashboards, visualizations, internal tools,
and anything you want to see at a glance. You can pin them to the channel HUD,
and they show up under the “Blocks” tab in your server’s app settings.
Built-in apps
Start.chat ships with 25 first-party apps across several categories.
Platform utilities — built into every workspace:
| App | What it does |
|---|---|
| Chat | Post messages, create threads, react, pin — all messaging as flow steps |
| Notify | Push notifications, channel alerts, user notifications as flow steps |
| Memory | Remember things across conversations with AI-powered recall |
| Calc | Arithmetic, percentages, aggregates on piped data |
| Data | Read, write, and query workspace data from chat or flows |
| Fetch | HTTP requests and endpoint health monitoring |
| LLMs.txt | Generate knowledge base context for AI assistants |
| Webhook | Generic webhook handling for any service |
Integrations — connect external services:
| App | What it does |
|---|---|
| GitHub | Subscribe to repos, receive webhooks, track issues and PRs |
| Linear | Sync issues and project updates with OAuth |
| Stripe | Payment tracking, customer data, subscription monitoring |
| Discord | Import a Discord server as a searchable knowledge base |
| Google Calendar | Event sync with OAuth |
| Slack | Send messages, receive notifications, sync channel activity |
| Notion | Search pages, query databases, create content |
| Postmark | Email sending and delivery tracking |
| Supabase | Database access and queries |
| PostHog | Analytics events, insights, and webhook alerts |
| Sentry | Error monitoring, issue tracking, alert notifications |
Infrastructure — deployment and hosting:
| App | What it does |
|---|---|
| Vercel | Monitor deployments, check project status, manage domains |
| Railway | Deployment monitoring, metrics, and logs |
| Cloudflare | DNS records, analytics, zone monitoring, Workers deploys |
Desktop — require the desktop app:
| App | What it does |
|---|---|
| Directory Scanner | Scan local directories and ingest files as searchable data |
| One Dollar Stats | Website analytics with chart history |
| Test | Simple test app for development |
Install any of these from Server Settings → Apps. Most connect with one click or an OAuth flow.
Marketplace
The marketplace is where you discover and install community-built apps. Browse it from Server Settings → Apps or on the start.chat website.
Apps are organized by category — integrations, analytics, devops, communication, productivity, and more. Apps that have been reviewed carry a verified badge, so you know they meet quality and security standards.
Anyone can publish an app to npm and submit it for listing in the marketplace. See Creating Apps for the full guide, including how to publish and submit.
Installing apps
Install apps from Server Settings → Apps or from the marketplace. Most connect with one click or an OAuth flow. You can also install apps from the CLI:
Terminal
The app lifecycle
Most apps follow the same shape:
- Define one or more actions with
createApp(). - Optionally add auth, options, and a scheduled backend.
- Persist data for dashboards, search, and AI context.
- Render that data with blocks or a full frontend.
- Expose the actions to chat, flows, and AI.
Creating blocks
Inline in a conversation
Start a code block with the block tag in any message:
When you send the message, start.chat detects the block code, creates it, and installs it to the current channel. The block renders in a sandboxed environment and can be pinned to the channel’s HUD bar.
Generated by HUD
Ask @hud to build a block for you. Describe what you want — “make a dashboard
that shows our Stripe payments” — and HUD will generate the code inline. You can
iterate on it by asking for changes.
Local development
On desktop, blocks sync to ~/start/{server-slug}/apps/. Edit block code in
your editor and changes push back to the server as drafts. This gives you a real
development workflow with your own tools while keeping everything connected to
your workspace.
App exports
An app can export up to three things, each serving a different purpose:
| Export | Purpose |
|---|---|
default | The main UI — renders when the app is opened |
suggestedFlowsAndBlocks | Suggested flow/block threads created on install |
backend | A service that runs on a schedule in the cloud |
A simple app might only export a default UI. A monitoring app might export all
three: a backend that fetches status data every 5 minutes, suggested threads
that seed useful flows or blocks, and a full UI with detailed charts.
Pinning apps to channels
Apps can be pinned to specific channels, where they appear in the floating HUD bar at the bottom of the channel. Click an app icon to open it. This lets different channels have different tooling — your #sales channel might have the Stripe dashboard pinned while #engineering has the GitHub tracker.
App configuration
Apps can define configurable options that server admins set during installation.
For example, the GitHub app has a repos option for which repositories to sync.
Options are defined in the app’s metadata and configured in Server Settings →
Apps.
Next steps
- Creating Apps — start with the app definition and action model
- Tools — see what app code can do at runtime
- Backends & Data — add sync and persistence
- Blocks — add inline dashboards and widgets