{
  "schema": "tesign-radar/item/1",
  "generated_at": "2026-09-17T01:56:13.055Z",
  "lang": "en",
  "slug": "breakscale",
  "url": "https://tesign.com/en/item/breakscale/",
  "alternates": {
    "ko": {
      "html": "https://tesign.com/item/breakscale/",
      "json": "https://tesign.com/item/breakscale/index.json",
      "markdown": "https://tesign.com/item/breakscale/index.md"
    },
    "en": {
      "html": "https://tesign.com/en/item/breakscale/",
      "json": "https://tesign.com/en/item/breakscale/index.json",
      "markdown": "https://tesign.com/en/item/breakscale/index.md"
    }
  },
  "name": "Breakscale",
  "use_label": "System-design simulator for learners",
  "one_liner": "Browser system-design simulator: build a topology, load it until it breaks, see why",
  "text": {
    "why": "System design is usually taught with static diagrams and rules of thumb like 'add a cache', which never explain why p99 latency falls off a cliff past 80 percent utilisation. Breakscale runs a discrete-event simulator in the browser, with finite server slots, gamma-distributed service times and measured percentiles, so that, in the README's account of the Retry Storm example, 100 offered requests per second become 348 hitting a database that is 99.9% busy while goodput is zero. It ships 33 components and 23 examples: sixteen teaching scenarios and seven reconstructions of Netflix, Spotify, Discord and other real architectures.",
    "take": "Instead of telling you to add a cache, it shows the numbers collapsing until you understand why.",
    "build": [
      "The engine in src/sim has no React or DOM dependency, so you can drive Engine from a script to generate teaching material or capacity-planning experiments, and add components or examples that model your own architecture."
    ],
    "who": [
      {
        "role": "Backend job seekers",
        "situation": "load-test the classic system-design interview topologies yourself"
      },
      {
        "role": "Mentors of junior engineers",
        "situation": "demonstrate retry storms, circuit breakers and sharding live"
      },
      {
        "role": "Service operators",
        "situation": "thought experiments that reproduce an outage"
      }
    ],
    "start": [
      {
        "command": false,
        "text": "# No install: https://breakscale.tech"
      },
      {
        "command": false,
        "text": "git clone https://github.com/xevrion/breakscale.git"
      },
      {
        "command": false,
        "text": "cd breakscale"
      },
      {
        "command": false,
        "text": "bun install"
      },
      {
        "command": false,
        "text": "bun dev   # http://localhost:5173"
      }
    ],
    "caveat": [
      "Licence MIT (the bundled Caveat font is separately under SIL OFL 1.1). Runs entirely in the browser with no account or telemetry, and a design stays on your machine unless you create a share link.",
      "Running locally requires Bun. The seven real-company architectures are teaching diagrams reconstructed from published material, not insider knowledge, as the README states.",
      "Workers IO (YC F26) is listed as title sponsor."
    ]
  },
  "cta": {
    "type": "try",
    "label": "TRY",
    "url": "https://breakscale.tech/"
  },
  "ready": "browser",
  "categories": [
    "education",
    "dev-tools"
  ],
  "categories_confirmed": true,
  "tags": [
    "system-design",
    "distributed-systems",
    "simulator",
    "education",
    "queueing-theory",
    "react"
  ],
  "platform": [
    "web"
  ],
  "license": {
    "spdx": "MIT",
    "scope": "permissive",
    "scope_text": "Use, change and redistribute, commercially too. Keep the notice.",
    "url": "https://spdx.org/licenses/MIT.html",
    "note": null,
    "open_source": true
  },
  "language": "TypeScript",
  "source_urls": {
    "canonical": "https://breakscale.tech/",
    "github": "https://github.com/xevrion/breakscale",
    "huggingface": null,
    "app_store": null,
    "sightings": [
      {
        "source": "github",
        "url": "https://github.com/xevrion/breakscale",
        "posted_at": "2026-09-04T12:00:00.000Z",
        "hn_url": null
      }
    ]
  },
  "numbers": {
    "as_of": "2026-09-16T21:00:00.000Z",
    "stars": 1156,
    "stars_unit": "GitHub stars",
    "stars_checked_at": "2026-09-15T19:35:08.110Z",
    "stars_observed_since_check": 0,
    "star_delta_24h": null,
    "star_delta_7d": null,
    "star_delta_30d": 9,
    "star_delta_unit": "GitHub stars gained in the window, GH Archive events summed to as_of",
    "spark_14d": [
      null,
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    "hf_likes": null,
    "hf_likes_observed_at": null,
    "hn_points": null,
    "hn_points_observed_at": null,
    "store": null,
    "method": "Star total = the value last checked on GitHub (stars_checked_at) + increases observed via GH Archive since. The 24h · 7d · 30d gains are GH Archive hourly events summed to the reference time (as_of). No score of ours."
  },
  "ranks": {
    "as_of": "2026-09-16T21:00:00.000Z",
    "all_time": null,
    "rising": {
      "24h": null,
      "7d": null,
      "30d": null
    },
    "categories": [
      {
        "category": "education",
        "label": "EDUCATION",
        "rank": 6
      }
    ]
  },
  "activity": {
    "pushed_at": "2026-09-14T23:10:50.000Z",
    "owner_type": "User",
    "open_issues": 14,
    "contributors": 14,
    "releases_count": 0,
    "latest_release": null,
    "checked_at": "2026-09-15T19:35:08.110Z",
    "core_checked_at": "2026-09-15T19:35:08.110Z"
  },
  "signals": [
    {
      "kind": "back",
      "label": "BACK CATALOG",
      "value": null
    }
  ],
  "images": {
    "og": "https://tesign.com/img/breakscale-3ba86788af.png",
    "cover": "https://tesign.com/img/breakscale-3ba86788af.png",
    "cover_width": 1529,
    "cover_height": 784,
    "gallery": [
      "https://tesign.com/img/breakscale-3ba86788af.png",
      "https://tesign.com/img/breakscale-c619065b43.png"
    ],
    "alt": "Breakscale's Retry Storm example: a top bar reading 100 requests per second offered, goodput 0/s, errors 100% and 118/s dropped, a canvas with Client → API Server → Database boxes showing the database 99.9% busy, and a handwritten-style explanation below",
    "tier": 2
  },
  "dates": {
    "first_seen_at": "2026-09-13T09:39:49.913Z",
    "source_created_at": "2026-08-23T06:21:21.000Z",
    "discovery_hours": 507.3080313888889,
    "launch_signal_at": "2026-09-04T12:00:00.000Z",
    "kept_at": "2026-09-14T19:27:43.638Z",
    "first_published_at": "2026-09-14T19:27:43.752Z",
    "updated_at": "2026-09-15T04:36:56.813Z",
    "ingestion_mode": "backfill"
  },
  "notes": [
    "This file was produced by the same build, from the same data, as the tesign.com item page. The text is editorial; the numbers are stored observations.",
    "null in the JSON means not observed — never zero. The Markdown writes [unconfirmed] for it.",
    "Star total = the value last checked on GitHub (stars_checked_at) + increases observed via GH Archive since. The 24h · 7d · 30d gains are GH Archive hourly events summed to the reference time (as_of). No score of ours.",
    "Reconstructed from archive data, not a live discovery.",
    "A summary, not legal advice."
  ]
}