We build our own software. And yours.
Celsa is a small, founder-led studio in London. We make products like ColdSoup, and we design and build websites and custom software for businesses that want it done properly.
- Websites
- Web apps
- SaaS products
- Online stores
- Internal tools
- AI features
- APIs & integrations
What we do
One studio, two ways we build.
Running our own products keeps us honest about what it takes to ship and support real software. Every client project gets the same standard.
Software we build and run ourselves.
We design, ship and support our own products, starting with ColdSoup, an AI-native office suite for teams.
Explore our products 02 / ServicesWebsites and software, built for you.
From a sharp marketing site to a full web app, we take your idea from the first call to launch, and look after it afterwards.
See services and pricingCapabilities
We design and engineer websites
- 01
Product design
Research, UX and interface design, from rough flows to a polished, clickable prototype.
- 02
Websites
Fast, responsive marketing sites with solid SEO foundations and content you can edit yourself.
- 03
Web applications
Dashboards, portals, booking systems and internal tools, shaped around how your team works.
- 04
E-commerce
Online stores with quick checkout, payments and the integrations that run the back office.
- 05
AI features
Assistants, search, summaries and automation built into your product where they genuinely help.
- 06
Care & hosting
Updates, monitoring, backups and small changes, so everything keeps working after launch.
Our product
ColdSoup: the office suite with AI in the room.
Docs, slides, sheets, chat and a calendar in one shared room, with an AI helper one click away on every page. Start a room, send one link, and your team is in. No sign-up, nothing to install.
- Edit together live and see who wrote what
- The AI helper works in the open, and every edit can be reverted
- Join from any browser with a room code or a link
Services
Clear scope. Clear prices.
Every project starts with a fixed, written quote. Here's where typical projects begin.
- 01Landing sitesOne-page and small sites, live within a few weeks.from £1,500
- 02Business websitesCustom-designed multi-page sites you can update yourself.from £3,500
- 03Online storesStorefronts with payments, stock and a fast checkout.from £5,500
- 04Custom softwareWeb apps, client portals and internal tools.from £12,000
- 05Product buildsMVPs and SaaS products, from idea to first customers.Get a quote
Start a project
Got something in mind? Let's build it.
Tell us what you're working on. We aim to reply within one working day with next steps and, if we're a good fit, a fixed quote.