## 1. The `twenty-client-sdk` Package (Source of Truth)
The monorepo package at `packages/twenty-client-sdk` ships with:
- A **pre-built metadata client** (static, generated from a fixed
schema)
- A **stub core client** that throws at runtime (`CoreApiClient was not
generated...`)
- Both ESM (`.mjs`) and CJS (`.cjs`) bundles in `dist/`
- A `package.json` with proper `exports` map for
`twenty-client-sdk/core`, `twenty-client-sdk/metadata`, and
`twenty-client-sdk/generate`
## 2. Generation & Upload (Server-Side, at Migration Time)
**When**: `WorkspaceMigrationRunnerService.run()` executes after a
metadata schema change.
**What happens in `SdkClientGenerationService.generateAndStore()`**:
1. Copies the stub `twenty-client-sdk` package from the server's assets
(resolved via `SDK_CLIENT_PACKAGE_DIRNAME` — from
`dist/assets/twenty-client-sdk/` in production, or from `node_modules`
in dev)
2. Filters out `node_modules/` and `src/` during copy — only
`package.json` + `dist/` are kept (like an npm publish)
3. Calls `replaceCoreClient()` which uses `@genql/cli` to introspect the
**application-scoped** GraphQL schema and generates a real
`CoreApiClient`, then compiles it to ESM+CJS and overwrites
`dist/core.mjs` and `dist/core.cjs`
4. Archives the **entire package** (with `package.json` + `dist/`) into
`twenty-client-sdk.zip`
5. Uploads the single archive to S3 under
`FileFolder.GeneratedSdkClient`
6. Sets `isSdkLayerStale = true` on the `ApplicationEntity` in the
database
## 3. Invalidation Signal
The `isSdkLayerStale` boolean column on `ApplicationEntity` is the
invalidation mechanism:
- **Set to `true`** by `generateAndStore()` after uploading a new client
archive
- **Checked** by both logic function drivers before execution — if
`true`, they rebuild their local layer
- **Set back to `false`** by `markSdkLayerFresh()` after the driver has
successfully consumed the new archive
Default is `false` so existing applications without a generated client
aren't affected.
## 4a. Logic Functions — Local Driver
**`ensureSdkLayer()`** is called before every execution:
1. Checks if the local SDK layer directory exists AND `isSdkLayerStale`
is `false` → early return
2. Otherwise, cleans the local layer directory
3. Calls `downloadAndExtractToPackage()` which streams the zip from S3
directly to disk and extracts the full package into
`<tmpdir>/sdk/<workspaceId>-<appId>/node_modules/twenty-client-sdk/`
4. Calls `markSdkLayerFresh()` to set `isSdkLayerStale = false`
**At execution time**, `assembleNodeModules()` symlinks everything from
the deps layer's `node_modules/` **except** `twenty-client-sdk`, which
is symlinked from the SDK layer instead. This ensures the logic
function's `import ... from 'twenty-client-sdk/core'` resolves to the
generated client.
## 4b. Logic Functions — Lambda Driver
**`ensureSdkLayer()`** is called during `build()`:
1. Checks if `isSdkLayerStale` is `false` and an existing Lambda layer
ARN exists → early return
2. Otherwise, deletes all existing layer versions for this SDK layer
name
3. Calls `downloadArchiveBuffer()` to get the raw zip from S3 (no disk
extraction)
4. Calls `reprefixZipEntries()` which streams the zip entries into a
**new zip** with the path prefix
`nodejs/node_modules/twenty-client-sdk/` — this is the Lambda layer
convention path. All done in memory, no disk round-trip
5. Publishes the re-prefixed zip as a new Lambda layer via
`publishLayer()`
6. Calls `markSdkLayerFresh()`
**At function creation**, the Lambda is created with **two layers**:
`[depsLayerArn, sdkLayerArn]`. The SDK layer is listed last so it
overwrites the stub `twenty-client-sdk` from the deps layer (later
layers take precedence in Lambda's `/opt` merge).
## 5. Front Components
Front components are built by `app:build` with `twenty-client-sdk/core`
and `twenty-client-sdk/metadata` as **esbuild externals**. The stored
`.mjs` in S3 has unresolved bare import specifiers like `import {
CoreApiClient } from 'twenty-client-sdk/core'`.
SDK import resolution is split between the **frontend host** (fetching &
caching SDK modules) and the **Web Worker** (rewriting imports):
**Server endpoints**:
- `GET /rest/front-components/:id` —
`FrontComponentService.getBuiltComponentStream()` returns the **raw
`.mjs`** directly from file storage. No bundling, no SDK injection.
- `GET /rest/sdk-client/:applicationId/:moduleName` —
`SdkClientController` reads a single file (e.g. `dist/core.mjs`) from
the generated SDK archive via
`SdkClientGenerationService.readFileFromArchive()` and serves it as
JavaScript.
**Frontend host** (`FrontComponentRenderer` in `twenty-front`):
1. Queries `FindOneFrontComponent` which returns `applicationId`,
`builtComponentChecksum`, `usesSdkClient`, and `applicationTokenPair`
2. If `usesSdkClient` is `true`, renders
`FrontComponentRendererWithSdkClient` which calls the
`useApplicationSdkClient` hook
3. `useApplicationSdkClient({ applicationId, accessToken })` checks the
Jotai atom family cache for existing blob URLs. On cache miss, fetches
both SDK modules from `GET /rest/sdk-client/:applicationId/core` and
`/metadata`, creates **blob URLs** for each, and stores them in the atom
family
4. Once the blob URLs are cached, passes them as `sdkClientUrls`
(already blob URLs, not server URLs) to `SharedFrontComponentRenderer` →
`FrontComponentWorkerEffect` → worker's `render()` call via
`HostToWorkerRenderContext`
**Worker** (`remote-worker.ts` in `twenty-sdk`):
1. Fetches the raw component `.mjs` source as text
2. If `sdkClientUrls` are provided and the source contains SDK import
specifiers (`twenty-client-sdk/core`, `twenty-client-sdk/metadata`),
**rewrites** the bare specifiers to the blob URLs received from the host
(e.g. `'twenty-client-sdk/core'` → `'blob:...'`)
3. Creates a blob URL for the rewritten source and `import()`s it
4. Revokes only the component blob URL after the module is loaded — the
SDK blob URLs are owned and managed by the host's Jotai cache
This approach eliminates server-side esbuild bundling on every request,
caches SDK modules per application in the frontend, and keeps the
worker's job to a simple string rewrite.
## Summary Diagram
```
app:build (SDK)
└─ twenty-client-sdk stub (metadata=real, core=stub)
│
▼
WorkspaceMigrationRunnerService.run()
└─ SdkClientGenerationService.generateAndStore()
├─ Copy stub package (package.json + dist/)
├─ replaceCoreClient() → regenerate core.mjs/core.cjs
├─ Zip entire package → upload to S3
└─ Set isSdkLayerStale = true
│
┌────────┴────────────────────┐
▼ ▼
Logic Functions Front Components
│ │
├─ Local Driver ├─ GET /rest/sdk-client/:appId/core
│ └─ downloadAndExtract │ → core.mjs from archive
│ → symlink into │
│ node_modules ├─ Host (useApplicationSdkClient)
│ │ ├─ Fetch SDK modules
└─ Lambda Driver │ ├─ Create blob URLs
└─ downloadArchiveBuffer │ └─ Cache in Jotai atom family
→ reprefixZipEntries │
→ publish as Lambda ├─ GET /rest/front-components/:id
layer │ → raw .mjs (no bundling)
│
└─ Worker (browser)
├─ Fetch component .mjs
├─ Rewrite imports → blob URLs
└─ import() rewritten source
```
## Next PR
- Estimate perf improvement by implementing a redis caching for front
component client storage ( we don't even cache front comp initially )
- Implem frontent blob invalidation sse event from server
---------
Co-authored-by: Charles Bochet <charlesBochet@users.noreply.github.com>
7.5 KiB
Create Twenty App is the official scaffolding CLI for building apps on top of Twenty CRM. It sets up a ready‑to‑run project that works seamlessly with the twenty-sdk.
- Zero‑config project bootstrap
- Preconfigured scripts for auth, dev mode (watch & sync), uninstall, and function management
- Strong TypeScript support and typed client generation
Documentation
See Twenty application documentation https://docs.twenty.com/developers/extend/capabilities/apps
Prerequisites
- Node.js 24+ (recommended) and Yarn 4
- Docker (for the local Twenty dev server)
Quick start
# Scaffold a new app — the CLI will offer to start a local Twenty server
npx create-twenty-app@latest my-twenty-app
cd my-twenty-app
# The scaffolder can automatically:
# 1. Start a local Twenty server (Docker)
# 2. Open the browser to log in (tim@apple.dev / tim@apple.dev)
# 3. Authenticate your app via OAuth
# Or do it manually:
yarn twenty server start # Start local Twenty server
yarn twenty remote add --local # Authenticate via OAuth
# Start dev mode: watches, builds, and syncs local changes to your workspace
# (also auto-generates typed CoreApiClient — MetadataApiClient ships pre-built — both available via `twenty-client-sdk`)
yarn twenty dev
# Watch your application's function logs
yarn twenty logs
# Execute a function with a JSON payload
yarn twenty exec -n my-function -p '{"key": "value"}'
# Execute the pre-install function
yarn twenty exec --preInstall
# Execute the post-install function
yarn twenty exec --postInstall
# Build the app for distribution
yarn twenty build
# Publish the app to npm or directly to a Twenty server
yarn twenty publish
# Uninstall the application from the current workspace
yarn twenty uninstall
Scaffolding modes
Control which example files are included when creating a new app:
| Flag | Behavior |
|---|---|
-e, --exhaustive |
(default) Creates all example files |
-m, --minimal |
Creates only core files (application-config.ts and default-role.ts) |
# Default: all examples included
npx create-twenty-app@latest my-app
# Minimal: only core files
npx create-twenty-app@latest my-app -m
What gets scaffolded
Core files (always created):
application-config.ts— Application metadata configurationroles/default-role.ts— Default role for logic functionslogic-functions/pre-install.ts— Pre-install logic function (runs before app installation)logic-functions/post-install.ts— Post-install logic function (runs after app installation)- TypeScript configuration, Oxlint, package.json, .gitignore
- A prewired
twentyscript that delegates to thetwentyCLI from twenty-sdk
Example files (controlled by scaffolding mode):
objects/example-object.ts— Example custom object with a text fieldfields/example-field.ts— Example standalone field extending the example objectlogic-functions/hello-world.ts— Example logic function with HTTP triggerfront-components/hello-world.tsx— Example front componentviews/example-view.ts— Example saved view for the example objectnavigation-menu-items/example-navigation-menu-item.ts— Example sidebar navigation linkskills/example-skill.ts— Example AI agent skill definition__tests__/app-install.integration-test.ts— Integration test that builds, installs, and verifies the app (includesvitest.config.ts,tsconfig.spec.json, and a setup file)
Local server
The scaffolder can start a local Twenty dev server for you (all-in-one Docker image with PostgreSQL, Redis, server, and worker). You can also manage it manually:
yarn twenty server start # Start (pulls image if needed)
yarn twenty server status # Check if it's healthy
yarn twenty server logs # Stream logs
yarn twenty server stop # Stop (data is preserved)
yarn twenty server reset # Wipe all data and start fresh
The server is pre-seeded with a workspace and user (tim@apple.dev / tim@apple.dev).
How to use a local Twenty instance
If you're already running a local Twenty instance, you can connect to it instead of using Docker. Pass the port your local server is listening on (default: 3000):
npx create-twenty-app@latest my-app --port 3000
Next steps
- Run
yarn twenty helpto see all available commands. - Use
yarn twenty remote add --localto authenticate with your Twenty workspace via OAuth. - Explore the generated project and add your first entity with
yarn twenty add(logic functions, front components, objects, roles, views, navigation menu items, skills). - Use
yarn twenty devwhile you iterate — it watches, builds, and syncs changes to your workspace in real time. CoreApiClientis auto-generated byyarn twenty dev.MetadataApiClient(for workspace configuration and file uploads via/metadata) ships pre-built with the SDK. Both are available viaimport { CoreApiClient } from 'twenty-client-sdk/core'andimport { MetadataApiClient } from 'twenty-client-sdk/metadata'.
Build and publish your application
Once your app is ready, build and publish it using the CLI:
# Build the app (output goes to .twenty/output/)
yarn twenty build
# Build and create a tarball (.tgz) for distribution
yarn twenty build --tarball
# Publish to npm (requires npm login)
yarn twenty publish
# Publish with a dist-tag (e.g. beta, next)
yarn twenty publish --tag beta
# Deploy directly to a Twenty server (builds, uploads, and installs in one step)
yarn twenty deploy
Publish to the Twenty marketplace
You can also contribute your application to the curated marketplace:
git clone https://github.com/twentyhq/twenty.git
cd twenty
git checkout -b feature/my-awesome-app
- Copy your app folder into
twenty/packages/twenty-apps. - Commit your changes and open a pull request on https://github.com/twentyhq/twenty
Our team reviews contributions for quality, security, and reusability before merging.
Troubleshooting
- Server not starting: check Docker is running (
docker info), then tryyarn twenty server logs. - Auth not working: make sure you're logged in to Twenty in the browser first, then run
yarn twenty remote add --local. - Types not generated: ensure
yarn twenty devis running — it auto-generates the typed client.