The free tool is the starting line. The framework is the engagement.
SDFC is a free tool we publish to help designers keep client projects consistent — sane defaults and enough structure to start well. It is not our framework. The frameworks we actually build on are licensed, confidential, and come with working together.
One free tool. Three frameworks.
SDFC is a free tool anyone can use. The three frameworks below it are what Stacklumen actually builds on — licensed or confidential, and progressively more capable. Access widens as we work together.
SDFC
Tier 1 · Public
A free starter tool for keeping client projects consistent. Not a framework.
- Cascade order and layout primitives
- Type, radius and colour basics
- Neutral defaults, bring your own brand
SDF
Tier 2 · Licensed
The template library. Sold under its own licence.
- Production page templates
- CMS structures, modelled and bound
- Component variants and states
SAF
Tier 3 · Confidential
The client-work framework. Every client project starts here.
- Full token architecture and scales
- Complete component and form system
- Interaction and motion patterns
- Confidential under the MSA
SLF
Tier 4 · Internal only
The Stacklumen framework. Never licensed or published.
- Powers every Stacklumen product
- Application surfaces and portals
- Trade secret, retained in full
Pick the one that fits.
Choose a path and we’ll ask only what’s relevant to it. A written proposal within 3 business days, weekly demos until launch, and full code ownership at handover.
I need a site built
Marketing sites, CMS-driven content, brand systems. Built on SDF, handed over editable.
Start a site brief →I need an app or internal tool
Portals, dashboards, billing, automation. Production applications on a modern stack.
Scope an application →I need ongoing help
Hosting, maintenance and a standing engineering partner rather than a one-off build.
See care plans →I’d rather refer work
Already build for clients? Pass on the projects you don’t take and earn 20% of what we collect.
Become a partner →What each tier grants.
SDFC — public
Free for unlimited personal and commercial projects. No attribution, no fee. You may not resell or redistribute SDFC itself as a template, clonable, course or component library.
SDF — licensed
The template library, sold under its own licence. Use in your projects as that licence permits. Not included with SDFC and not sublicensable.
SAF — confidential
The framework applied to client work. Disclosed only under the confidentiality terms of our Master Service Agreement. It is a trade secret, remains Stacklumen property, and may not be reused, extracted or shared beyond the engagement.
SLF — internal
Stacklumen’s own framework, powering our products. Never licensed, sold, published or disclosed — to clients or anyone else.
SDFC™, SDF™, SAF™, SLF™ and Stacklumen™ are unregistered trademarks of Stacklumen, claimed under common law. No trademark rights are granted by any tier — build with SDFC freely, but do not use the marks to name or promote your own product. SAF and SLF are maintained as trade secrets and are protected by contract rather than by public licence. © 2026 Stacklumen. All rights reserved. Full terms at /legal/copyright, /legal and /msa.