A drawing can't tell you what breaks. Keystone can.

Diagrams rot because each one is a separate drawing. Keystone keeps one model underneath them all, so it can answer questions a drawing never could. Like this one.

Request access See every feature

In Keystone, selecting an object shows everything that depends on it.

It runs, not just renders

Most architecture tools can only draw your system. Keystone can run traffic through it. Put a small rule on an object, like a rate limit or a cache hit ratio, send traffic in, and watch where it piles up.

The rules are real code: a few lines of JavaScript each, with starter rules to copy. Put one on a technology, like PostgreSQL, and every Postgres in the model gets it. Try the simulator

Keystone rule editor showing a JavaScript rate limit rule for the API, next to the rules on each object — The rate limit on the API, in 18 lines. Postgres gets its rule from the PostgreSQL technology.

Your servers, your sign-in

Your architecture map lists every system, every database and every weak spot you have. Keystone runs on your own infrastructure, behind your own identity provider.

SAML and OIDC come with every install. Map your provider's groups to roles and people land with the right access on their first sign-in. How self-hosting works

Keystone identity provider settings with SAML and OIDC, email domains and a group-to-role map — Organization settings: one identity provider, SAML or OIDC, with groups mapped to roles.

How Keystone compares

Every tool here is good at something. This is about which one fits a shared, living architecture model.

Keystone compared with IcePanel, Structurizr and drawing tools
	Keystone	IcePanel	Structurizr	Lucidchart, draw.io, Miro
Shared model under the diagrams	Yes	Yes	Yes	No, shapes only
Visual editor, no code needed	Yes	Yes	No, you write a DSL	Yes
Step-by-step flows	Yes	Yes	Dynamic diagrams	No
Drafts for proposed changes	Yes	Yes	Via git branches	No
Traffic simulation	Yes	No	No	No
Run it on your own servers	Yes	No, cloud only	Yes	draw.io only
SSO in every install	SAML and OIDC	Paid plans	Depends on edition	Varies by tool and plan

Based on each vendor's public docs as of September 2026. Something out of date? Tell us at support@keystone-app.io and we'll fix it.

Keystone vs IcePanel: Same modelling ideas, on your own servers, plus simulation.
Keystone vs Structurizr: A model everyone can edit, not just people who write DSL.
Keystone vs drawing tools: Why Lucidchart, draw.io and Miro diagrams drift.

Who it's for

Architects: One source of truth, and a place to record why decisions were made.
Platform and SRE teams: Find the bottleneck before the incident does.
Engineering managers: Know who owns what, and review changes before they land.
New hires: Understand the system without booking ten meetings.
Security and compliance: Keep the architecture map inside your own network.

Questions

Is Keystone a C4 model tool?

Yes. Keystone ships with C4-style object types and diagrams, and lets you add your own object types when C4's four levels don't fit. New to C4? Read our plain-English guide.

Can I host Keystone myself?

Yes. Keystone runs on your own servers with Docker and Postgres. Your architecture data never leaves your network. More on self-hosting.

Which features cost extra?

None. Every install gets every feature, including SAML and OIDC single sign-on, the API, webhooks and simulation.

Do non-engineers need to learn a diagram language?

No. Keystone is a visual editor in the browser. Engineers who want automation can use the REST API and YAML or JSON import.

What does the simulation do?

You write small rules for objects or technologies, like rate limits or cache hit ratios, in a few lines of JavaScript. Then you send traffic through the model. Keystone shows where messages pile up or fail, with a step-by-step trace for each one.