xevrion / breakscale

Open Breakscale |
 Documentation |
 VS Code |
 MCP server |
 Contributing 
 A system design simulator where every number is measured. 
 Build a system, load it until it breaks, and watch why.
 Title sponsor 
 Workers IO (YC F26) sponsors Breakscale. Simulation environments for verifying mission-critical software. 
 The Retry Storm example at 100 requests a second. The database is 99.9% busy and goodput
 is zero, because retries have turned 100 offered requests into 348 hitting a database that was
 already full. 
Breakscale lets you put load balancers, caches, databases, queues and 29 other components on a
canvas, wire them into a system, and drag the traffic up until something gives. What you see
while it happens is a real discrete-event simulation: latency percentiles climbing, queues
filling, circuit breakers tripping, and whole systems collapsing into retry storms, all measured
from individual simulated requests rather than drawn to look plausible.
It runs in your browser, inside VS Code, and inside your AI assistant, which can read your code,
draw your architecture, and tell you where it breaks.
## Why it exists
Most system design material is static diagrams and rules of thumb. "Add a cache." "Use a queue."
That makes it hard to build any intuition for why p99 latency falls off a cliff once utilisation
passes 80 percent, or how a short timeout with a couple of retries turns one slow database into a
total outage.
Breakscale runs the experiment instead of describing it. Load the Retry Storm example, drag the
traffic up, and watch goodput fall to zero while the database is still working flat out, because
every request it finishes has already been abandoned by a caller that gave up waiting.
## Three ways to use it
### In your browser
Open breakscale.tech, pick an example from the left, and raise the
traffic slider until something turns red. There is no account to make. A design stays in your
browser unless you share it, and a shared design is encrypted before it leaves, with the key kept
in the part of the link that browsers never send to a server.
### In VS Code
Install Breakscale from the Marketplace
and run **Open Breakscale** from the command palette. The whole simulator opens in a panel beside
your code, with the same engine and examples as the website, and it works offline. Designs you
save there live in VS Code's own storage; a share link or a `.breakscale` file moves one between
the editor and the website.
### With your AI assistant
Breakscale is also an MCP server, so Claude, Copilot, Cursor, Codex and other
assistants can use it for you. Point one at a repo and ask it to turn the architecture into a
design, or just describe a system, and it builds the design, runs it through the same engine, and
comes back with measured numbers and a breakscale.tech link that opens it.
The server is hosted at `https://mcp.breakscale.tech/mcp`, so there is nothing to install. In
claude.ai, add that URL under **Customize > Connectors > Add custom connecto