# algorithm-visualizer is the React app, and the algorithms live elsewhere

> Algorithm Visualizer is a browser platform that animates algorithms by interpreting a stream of visualization commands emitted by your code, and this repository is only the front end of a four-repository system: a React app, a server that compiles and runs code, an algorithms repository, and tracer libraries per language. The manifest tells the rest of the story, with two dependencies pinned to the literal string latest, a native node-sass dependency and a dev proxy pointing at a server that is not in this tree.

**algorithm-visualizer/algorithm-visualizer** — GitHub describes it as :fireworks:Interactive Online Platform that Visualizes Algorithms from Code. The repository metadata lists JavaScript as its primary language. The metadata lists the MIT license. This article stays within the project description and details documented in the GitHub repository README.

- Repository: https://github.com/algorithm-visualizer/algorithm-visualizer
- Website: https://algorithm-visualizer.org/
- Stars: 48,871 · Forks: 7,579
- Language: JavaScript
- License: MIT
- Published: 2026-08-13 · Updated: 2026-08-18 · Language: en
- Canonical page: https://hysenlabs.com/projects/algorithm-visualizer-algorithm-visualizer

## The animation is a command stream, and a tracer has to produce it

The page explains the mechanism in one sentence and then splits it across repositories. The web app is written in React, contains the UI components, and interprets commands into visualizations. The commands come from tracer libraries written in each supported language, whose stated job is to extract visualizing commands from code. The server compiles and runs that code and serves the app, and a separate algorithms repository holds the visualizations listed in the site menu. Read that as a contract rather than a convenience. Your code has to be instrumented to emit commands, a tracer has to exist for your language, and the server has to be able to execute it. A language with no tracer produces no animation, and nothing on the page suggests the app can read ordinary code and work out what to draw.

## The dev proxy targets localhost:8080, so the frontend cannot run alone

The manifest sets a proxy to a fixed address:

```json
"proxy": "http://localhost:8080",
```

That port belongs to the server repository, which is described as serving the web app and providing the APIs it needs on the fly, with GitHub sign in and compiling and running code given as the examples. So the three scripts in this manifest, all of them thin wrappers around react-scripts for start, build and test, are enough to open a dev server and nothing else useful. A local setup is two repositories running at once, and the parts you would most want to inspect, the API that executes user code and the sign-in flow, are not in this tree at all. The repository does include a .gitpod.yml, so a hosted workspace is the intended shortcut for that two-repository arrangement.

## Two dependencies are pinned to the string latest

Most of the dependency list uses caret ranges: react and react-dom at 16.8.6, react-scripts at 3.0.1, axios at 0.19.0, chart.js at 2.8.0, redux at 4.0.1, the react-router family at 5.0.1. Two entries are different. bluebird is declared as latest and brace is declared as latest, and nothing pins them. The practical effect is that the manifest does not describe a build: a fresh install resolves those two packages to whatever version is published at that moment, which is not necessarily what the code was written against. A package-lock.json is committed, so the frozen set exists, and that lockfile rather than the manifest is the artefact to trust. The rest of the list shows the same care elsewhere, including react-fontawesome pinned to an exact 0.1.4, so the two loose entries look like oversights rather than a policy.

## node-sass 4.12 and a Create React App 3 toolchain age in place

The engine field declares node >=10.15.3 and no upper bound, which means the manifest states a floor from a previous era and says nothing about the ceiling. The toolchain matches that floor: react-scripts 3.0.1, eslintConfig extending react-app, and react 16.8.6 with react-ace for the editor pane and react-chartjs-2 over chart.js 2.8.0 for the visual output. The entry that will cost you the most time is node-sass at 4.12, a native module that has to compile against the local toolchain rather than ship as pure JavaScript. Native modules of that vintage carry prebuilt binaries for the runtimes of their era, so on a current Node release the install is where this manifest gets interesting, and the missing upper bound in engines gives you no warning in advance. The project is JavaScript throughout, with a jsconfig.json rather than a TypeScript configuration.

## Ejecting is offered as a script, and it is a one-way door

The four scripts are start, build, test and eject, and the fourth one deserves a sentence of its own. Ejecting replaces the generated configuration with real files you own, which is the escape hatch from a framework that hides its build. It is also irreversible in practice, because a fork that has ejected no longer receives the upstream toolchain and has to maintain what used to be generated, including the lint and browserslist setup the manifest declares. The browserslist block shows what that setup is doing: production output is transpiled for a broad tail, greater than 0.2% usage, not dead and not op_mini all, while development targets only the last version of Chrome, Firefox and Safari. That asymmetry has a consequence. You test on current browsers and ship for older ones, so a rendering difference can appear only in the production build.

## The last push was 2024-06-09 and the manifest still says 2.0.0

Maintenance is the fact to weigh before you plan around this project. The last push to the master branch is dated 2024-06-09, more than two years before now, and the repository has no GitHub releases, so there is no tag to pin, no changelog to read and no statement that development has stopped. The repository is not archived. The manifest version is 2.0.0, which tells you the front end is on its second major shape, and that is the whole of the version information available to a consumer. For anyone evaluating the platform, the practical split is this: the hosted site at algorithm-visualizer.org is the product, this repository is one component of it, and a broken visualization on the site is a question for whichever repository owns that algorithm, not for the React app.

## Contributing to the platform means choosing a repository first

The contributing section opens by saying the project consists of multiple repositories, each playing a role, and then lists four of them with a one-line description each. The web app you are reading about is the React one. The server serves it and provides the APIs. The algorithms repository holds the visualizations shown in the site menu, and the page notes that contributions there directly affect the educational content available on the platform. The tracers are the per-language libraries. The practical consequence for a newcomer is that the question you are holding decides the destination: adding an algorithm is a pull request against a different repository, changing how commands turn into frames is a pull request here, and supporting a new language is a third. The tree supports that split too, with a branding directory, a public directory, a code of conduct and its own contributing file for this piece alone.

## Conclusion

Adopt Algorithm Visualizer when you want to show an algorithm running rather than describe it, and when a tracer library exists for your language, because the animation is produced by that tracer rather than inferred from arbitrary code. Do not adopt it as a library you will vendor, since this repository is the web front end of a hosted service and the interesting parts, the server that compiles and runs code and the algorithm content, are separate projects. Verify four things before you build on it. Check the version you are installing, because the last push was 2024-06-09, the manifest still says 2.0.0 and there are no GitHub releases to pin. Freeze the lockfile rather than trusting the manifest, since bluebird and brace are declared as latest and will resolve to whatever they publish today. Plan for two repositories in a local setup, because the dev proxy targets http://localhost:8080 and that server is a different project. And check that a tracer exists for your language before you promise anyone a visualization, since the tracers are the part that has to exist first.

## FAQ

### What is an algorithm visualizer?

On this project it is a browser platform that visualizes algorithms from code: the React app interprets commands into visualizations, tracer libraries in each supported language extract those commands from the code you write, and a separate server compiles and runs it. The site also carries tutorials, articles and videos alongside the running visualisations.

### How do I use Algorithm Visualizer?

The live demo is the site itself at algorithm-visualizer.org, where you pick an algorithm from the side menu and watch it run. To add to it rather than just use it, the page splits the work across repositories: the React web app, the server that provides APIs such as sign in and code execution, the algorithms repository for the side menu content, and the tracer libraries for each language.

### Is there an Algorithm Visualizer extension for VS Code?

The page does not mention a VS Code extension or any editor integration. What it describes is a browser platform with a React app, a separate server that compiles and runs code, and tracer libraries written in each supported language, with the editor inside the web app provided by the react-ace dependency.

## Sources

- [Official documentation](https://algorithm-visualizer.org/)
- [Official README](https://github.com/algorithm-visualizer/algorithm-visualizer#readme)
- [Project repository](https://github.com/algorithm-visualizer/algorithm-visualizer)

---

Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/algorithm-visualizer-algorithm-visualizer