Rastrillo: build and ship better apps

What does better mean?

There are many tradeoffs involved when building software, but some choices are objectively better.

Value

More value for money
Reducing reliance on big tech
Self-hosting as first class

Control

Control where data lives
Continuous backups
Robust deployments anywhere in the world
Different versions for different users

Speed

Ship faster than ever
Iterating on real apps rather than prototypes
Massive runtime performance

Quality

Uncompromising user experiences
More secure by default
Accessibility compliance ready from day one

Go faster

The Go programming language is the perfect blend of fast—both compile and runtime—and rich in features

The great runtime performance of Go
Full HTML pages rendered in milliseconds
Delightfully fast build, compile, build dev loops
A rich ecosystem of libraries across the full stack, from HTTP requests to HTML and JSON rendering

Built by agents, for agents and humans

Designed to be easy to use, whether assisted or not

actions/

index.GET.goGET /
posts/[id]/index.GET.goGET /posts/{id}
admin/posts/index.GET.goGET /admin/posts
admin/posts/[id]/publish.POST.goPOST /admin/posts/{id}/publish
admin/posts/[id]/delete.POST.goPOST /admin/posts/{id}/delete

Real files from examples/blog, one per route.

Declarative manifestsDescribe a resource in TOML and generate its store, actions and screens.
A CLI for common tasksrastrillo new starts an app, rastrillo dev rebuilds as you edit, and rastrillo migration writes schema changes.
Filesystem-backed actionsEach route is one file, named for its path and method.
Readable GoGenerated code is plain Go, committed and reviewed like your own.

Where we’re going, we don’t need rails

Experience the pure joy of putting a file on a remote host and having a working web app. Rastrillo apps are full stack: database, HTTP server, HTML, CSS, JS all in a single binary that runs anywhere. What’s old is new again.

Let’s de-jank the web, one app at a time

The push toward SPAs was supposed to lead to faster apps and better experiences, but we got the opposite: computers are faster than ever but web apps feel slower. Rastrillo apps encourage instant page loads, server-rendered HTML, with uncompromising client-side experiences with progressively-enhanced JS.

Single-page app

Rastrillo

A design system for everyone

The Rastrillo design system is a robust design system using elegant, semantic markup to create usable baseline styles for your apps.

Preview theme Light Dark

<header rst-page-header>
  <div rst-page-header-titles>
    <h1>Requests</h1>
    <p rst-page-header-sub>Newest first.</p>
  </div>
  <a rst-btn="primary" href="/requests/new">New request</a>
</header>
<nav rst-seg-tabs aria-label="Requests">
  <a href="/requests" aria-current="page">All</a>
  <a href="/requests?open">Open</a>
  <a href="/requests?resolved">Resolved</a>
</nav>
<div rst-card style="--rst-cols: 1fr auto">
  <div rst-lrow>
    <a class="rst-nm" href="/requests/4471">Invoice never arrived</a>
    <span rst-status rst-tone="warning">Waiting</span>
  </div>
  <div rst-lrow>
    <a class="rst-nm" href="/requests/4468">Card declined</a>
    <span rst-status rst-tone="neutral">Open</span>
  </div>
</div>
<!-- Open and Resolved panes (rst-stats, and rst-box
     with rst-detail and rst-switch) sit here, hidden
     until their tab is clicked -->
<!-- ...plus a few lines of script for tabs and toast -->

Plain HTML with rst- attributes. Custom elements, ids, and classes are left clear for your apps.

Get good-looking admin screens out of the box
A full set of configurable design tokens
A host of the most common components
Light: <20KiB gzipped
WCAG AA 2.2 accessibility audit-ready
Proper hierarchy-based mobile navigation

Try it out

Get started

Choose how to start With an agent By hand

Paste this into your agent of choice

Build me a [describe your app] with Rastrillo. Read https://rastrillo.org/SKILL.md first. Then install the CLI with go install amadan.net/rastrillo/rastrillo/cmd/rastrillo@latest, run rastrillo new, and keep go test ./... passing as you go.

Clone the repo

git clone https://github.com/rastrilloorg/rastrillo && cd rastrillo/examples/notes

2
Run it
```
CGO_ENABLED=0 go run ./cmd/notes -addr localhost:8080
```
Sign up, write a note. Open a private window, sign up as someone else, and try to reach the first note by URL: 404.

Start your own

go install amadan.net/rastrillo/rastrillo/cmd/rastrillo@latest
rastrillo new myapp && cd myapp && go mod tidy && go test ./...

Deployment

Rastrillo apps compile to a single binary, so they will run trivially on any deployment stack. For fast-simple CARLOS-native deployment, reach for CARLOS platform, and to get started immediately, use Carloku.

Choose how to deploy With an agent By hand

Ask your agent:

Deploy this app to Carloku

1
Install the platform binary
```
brew install carlosframework/tap/carlos
```

Build your app for the target host

GOOS=linux GOARCH=arm64 go build -o myapp ./cmd/myapp

3
Deploy it
```
carlos deploy --app myapp ./myapp
```
Ships, promotes and watches your hosts until the new build is live.

A growing list of features for a whole variety of proven use-cases

Data and storage

Database: GORM on pure-Go SQLite, with split writer and reader pools.
Migrations: Additive migrations, applied at startup in a safe order.
Mergeable store: Append-only event streams with a deterministic merge.
Blobs: Content-addressed files on object storage, with presigned URLs.

Sign-in and security

Sessions: Revocable server-side sessions, with step-up re-auth for sensitive routes.
CSRF: An origin check on every mutating request. No tokens to forget.
Owner scoping: Someone else's row answers 404, proven by a two-user test suite.
Magic links: Email sign-in that upgrades to Keymail where it can.
Passwords: Email and password, rate-limited per account.
Passkeys: WebAuthn as a second factor, with recovery codes.
Encryption: P-256 sealing and signing, with a matching browser module.

Screens and content

Design system: 27 components and design tokens, light and dark.
Manifests: Declare a resource and get its store, actions and screens.
Localization: Locale-aware routes, translations with fallback, and a catalog check before you ship.
Scaffolding: rastrillo new gives you a working app with passing tests.

Background work

Jobs: Background tasks with a status page that works without JavaScript.
Live updates: Server-Sent Events where supported, plain polling where not.
Scheduling: Timers and recurring jobs that survive restarts and sleeping apps.

Agents and platform

SKILL.md: The whole framework in one file an agent can load.
Agent tools: Actions opt in as tools, with consent and attribution.
Hibernation: Apps sleep when idle and wake on the next request.
One binary: go build produces the whole app. No bundler, no runtime.

Build and ship better apps