strudel.cc

What is Strudel REPL?

Strudel REPL is a browser-based live coding environment for making music. You type short patterns of code, press play, and hear them loop immediately — no installation, no DAW, just a web page and a keyboard. It is a JavaScript port of TidalCycles, a long-established pattern language originally used in the SuperCollider ecosystem, so the ideas and much of the syntax will look familiar if you have seen Tidal before.

What it is good at

• Fast feedback loops. Because patterns are evaluated as you edit, Strudel suits improvisation, sketching and performance rather than careful multitrack production.
• Patterns over piano rolls. You describe rhythm and pitch as text — repeating, stacking, offsetting and transforming sequences — which makes generative and algorithmic ideas easy to try.
• Sharing and learning. Code is compact enough to paste into a chat or forum, so it works well for study groups, workshops and jam sessions.
• Zero setup. Anything with a modern browser and audio output can run it, which lowers the barrier for classrooms and casual experimentation.

Where it is less suitable

• Detailed mixing, automation lanes and audio recording are not the point; a traditional DAW remains better for finished releases.
• Typing code is a real skill barrier if you have never programmed. The payoff is speed once patterns click, but the first hour can feel cryptic.
• Browser audio and CPU limits mean very dense patterns may glitch, and results depend on your machine and browser.

Who tends to use it

Live coders performing sets, teachers introducing algorithmic music, programmers curious about sound, and producers who want rhythmic ideas they later rebuild elsewhere.

A practical next step

Open Strudel REPL and try one short pattern with a drum sound, then change a single number and listen. If you want background on the language it ports, see TidalCycles; if you prefer a general-purpose creative coding environment in the browser, p5.js is a different route with a much broader canvas focus. Choose Strudel when your goal is rhythmic pattern play in the browser; choose a DAW when your goal is a polished mix.

How do I start making music with Strudel REPL in my browser?

Open Strudel REPL in a modern desktop browser and press Ctrl+Enter (or Shift+Enter, depending on your build) to evaluate the code that is already on the screen. You do not install anything or create an account: the default pattern plays immediately, which is the fastest way to hear what the environment does.

Strudel is a JavaScript port of the TidalCycles pattern language, so the mental model is patterns, not a timeline. You write short expressions that describe events, and the scheduler repeats and transforms them.

A first edit that teaches the model

Change one thing at a time and re-evaluate:

• Swap a sound name, e.g. replace bd with sd to move from kick to snare.
• Add a modifier such as fast(2) to double the speed of a pattern.
• Chain patterns with a comma inside brackets to layer them.

Each edit is audible within a second or two, so you learn the syntax by ear rather than by reading a manual first.

Where Strudel fits, and where it does not

A practical next step

Pick a two-bar rhythm you like, write it as one line, then vary it three ways using fast, slow and every. That single exercise covers most of what makes pattern-based live coding click, and it keeps your session inside the browser.

If you want a second reference point for the same family of tools, TidalCycles itself lives at TidalCycles, and the broader live-coding community around it is easy to find from there.

Can I use Strudel REPL without installing any software?

Yes. Strudel REPL runs in the browser, so you can start writing patterns and hearing results without installing a desktop application or a local development environment. You open the page, type code, and evaluate it to produce sound.

That makes it unusually approachable for live coding: a laptop, a browser and working audio output are the main practical requirements. It also means the same code can be shared as a link or pasted into a session, which is useful for teaching, jam sessions or sketching an idea on a borrowed computer.

What "no install" does and does not cover

• No install: the editor, pattern language and audio engine run in the page.
• Still needed: a modern browser and a reliable internet connection while you use it.
• Not the same as offline: if you need to work without a network, a browser-based tool is a weaker fit than a locally installed live-coding environment.
• Not the same as production software: for multitrack recording, mixing or plugin-heavy workflows, you will eventually move the material into a DAW.

A concrete first session

Open Strudel REPL, type a short pattern such as a simple kick and hi-hat sequence, and evaluate it. Change one value at a time — tempo, a sound name, a rhythm — and re-evaluate. This is the core live-coding loop: edit, listen, adjust. If you already know TidalCycles, the pattern language will feel familiar; if you do not, treat the first session as learning a small vocabulary rather than a full programming course.

When to choose it

Use Strudel REPL when you want the fastest possible path from idea to sound, when you are teaching pattern-based music, or when you want to share runnable musical code. Choose a locally installed environment instead when you need offline work, low-level audio control or integration with a larger production setup.

How does Strudel REPL's JavaScript port of TidalCycles differ from the original TidalCycles?

Strudel REPL runs TidalCycles-style pattern language in the browser via JavaScript, so the main difference is the runtime environment and the syntax you write, not the underlying idea of pattern-based music.

What changes in practice

• Language and syntax: Original TidalCycles is a Haskell library; you write Haskell expressions and hear them through SuperCollider and SuperDirt. Strudel ports the pattern language to JavaScript, so you write JavaScript-flavored expressions and evaluate them directly in the page.
• Setup: TidalCycles typically requires installing Haskell, an editor plugin, SuperCollider, and SuperDirt. Strudel runs in the browser, so you can start making sound without a local toolchain.
• Audio path: TidalCycles sends patterns to SuperDirt for synthesis and sampling. Strudel uses browser audio (Web Audio) and its own sample loading, so the sound sources and effects differ from a SuperDirt setup.
• Sharing and portability: Because it is a web page, Strudel patterns are easy to share as URLs or code snippets. A local TidalCycles setup is tied to your machine and installed samples.
• Ecosystem and extensions: TidalCycles has a long history of Haskell-side functions, editor integrations, and SuperDirt sample packs. Strudel's JavaScript port has its own function set and browser-oriented sample sources; not every Haskell-side trick or SuperDirt-specific feature maps one-to-one.

Who each suits

• Choose Strudel if you want to try live coding quickly, share patterns with others, or work on a machine where installing a full audio stack is impractical.
• Choose original TidalCycles if you want deep Haskell-level control, a mature SuperDirt sample/synth ecosystem, or an existing local setup you already know.

A practical next step: open Strudel REPL and run a short pattern, then compare it with a TidalCycles example you know. If the JavaScript syntax and browser audio feel sufficient, Strudel removes most setup friction; if you rely on SuperDirt-specific instruments or Haskell functions, the original remains the closer fit.

What kind of sounds and patterns can I create with Strudel REPL?

Strudel REPL is a browser-based live coding environment that brings the TidalCycles pattern language to JavaScript. In practice, that means you write short lines of code and hear the result immediately — loops, beats, melodies, textures and generative variations — without installing anything beyond a browser tab. The "REPL" part matters: you evaluate code, listen, tweak a number or a function, and re-evaluate while the pattern keeps running.

What you can build

• Rhythmic patterns: step sequences, Euclidean rhythms, polyrhythms and shifting accents built from pattern functions rather than a piano roll.
• Drum and percussion loops: sample-based beats where each hit is triggered by a pattern, so you can vary density, timing and layering live.
• Melodic and harmonic material: note patterns, arpeggios, chord stabs and basslines, with the ability to transpose, reverse, slow down or speed up patterns as transformations.
• Textural and ambient layers: long, sparse events, filtered noise, drones and slowly evolving structures that suit background or installation work.
• Generative and probabilistic music: random choices, weighted picks, conditional events and pattern mutations — useful when you want a piece that never repeats exactly.
• Live performance material: since patterns are code, you can build a set as a series of small edits, bringing elements in and out by changing a value or commenting a line.

How patterns differ from a DAW

The trade-off is real: you get speed and flexibility in expressing rhythmic and generative ideas, but you need to be comfortable with code syntax, and complex arrangements can become harder to visualise than in a timeline-based editor.

A concrete scenario

Say you want a four-on-the-floor pulse with a syncopated hat and a bassline that drifts. You would write one pattern for the kick, one for the hats with an offset or Euclidean rhythm, and one for the bass notes, then layer them. To make it evolve, you change a single number — a density, a probability, a transposition — and re-evaluate. That is the core workflow: small code edits as musical decisions.

Next step

Open Strudel REPL in a browser, start from a short example pattern, and change one value at a time — a sample name, a number of steps, a probability — listening after each evaluation. If you already know TidalCycles, expect the same pattern concepts in JavaScript syntax; if you are new to live coding, begin with a single drum pattern before layering melody and texture.

Can I share or collaborate on Strudel REPL code with others?

Yes. Strudel REPL is a browser-based live coding environment that ports the TidalCycles pattern language to JavaScript, and it is built around the idea of code you can pass around rather than a closed project file. Your pattern is just text, so sharing it is mostly a matter of getting that text to someone else and having them paste it into the editor.

Practical ways to share

• Copy and paste the code. The simplest route: send your pattern as plain text in a chat, email, or document. Anyone can drop it into the editor and run it immediately.
• Share a link to a running session. Strudel-style environments typically encode the pattern in the URL, so a link can open with your code already loaded. This is the most convenient option for quick feedback, and it is worth testing with a short pattern before relying on it for a long piece.
• Use a public code host. Paste the pattern into a gist or repository so it has a stable address and a revision history. This suits teaching examples, reusable snippets, and anything you expect to change over time.
• Pair in real time by screen sharing. Live coding is often performed and taught this way. One person drives the editor while the other listens and suggests changes, which works well when you want to discuss why a pattern sounds the way it does.

Where the limits show up

Sharing text is easy; simultaneous editing is the harder problem. Unless the environment offers a built-in collaborative session, two people editing the same URL will not see each other's keystrokes. In practice, teams work around this by agreeing on one driver at a time, or by keeping the pattern in a shared file and pasting it in when they want to hear it.

There is also an audio constraint. Each person hears sound generated on their own machine, so timing, volume balance, and any samples you load locally will differ between listeners. If a pattern depends on a sample you added yourself, the other person may hear silence or an error until they load the same source.

A sensible next step

Start with a short pattern, copy its URL, and open it in a second browser window or send it to a collaborator. If the code arrives intact, link sharing is your default. If it does not, fall back to pasting the raw text into a gist and treat that as the source of truth. For longer sessions, decide up front who is driving and how you will hand off, because that convention matters more than any feature.

For background on the pattern language itself, see TidalCycles.