What is a composable tech stack?
The term 'composable' keeps appearing in tech conversations. Here's what it actually means, when it's useful, and when it's overcomplicating things.
If you've attended a web conference or read a tech blog in the past year, you've probably encountered the word "composable." It's become one of those terms that gets used so broadly it's started to lose meaning. So what does it actually mean in practice? Vendors slap it on everything. But the underlying idea is genuinely useful, so it's worth cutting through the marketing.
A composable tech stack means choosing individual, specialised services for each function of your digital presence and connecting them via APIs, rather than using one monolithic platform that handles everything. Instead of WordPress doing your content management, e-commerce, forms, email, and SEO all in one installation, you might use Sanity for content, BigCommerce for products, Resend for transactional email, and Vercel for hosting, with a Next.js frontend pulling everything together.
Why the idea has legs
The argument for composability is flexibility. If your e-commerce provider raises prices or your CMS stops innovating, you can swap that one component without rebuilding your entire site. Each service focuses on doing one thing well rather than doing ten things adequately. You get better performance because you're not loading a monolithic application for every request. And your frontend isn't constrained by any single backend's templating system.
I've been building this way for most of my client work over the past eighteen months, and the benefits are real. A recent project uses Sanity for content, BigCommerce for a product catalogue, and a Next.js frontend, each piece does its job well, and the client's content editors and product managers work in interfaces purpose-built for their tasks.
The honest downsides
Composable stacks are more complex to set up and maintain. Instead of one system to update and one set of documentation to read, you're managing several services, several APIs, several billing relationships. When something breaks, you need to diagnose which service is the source of the problem. You need developers who are comfortable with API integration and understand how data flows between services.
The cost can also be higher, at least initially. A WordPress site on £16/month hosting is hard to beat on price. A composable stack with Sanity (£79/month for their Team plan), Vercel (usage-based, typically £16-50/month for a moderate site), and BigCommerce (£23/month+) adds up. The total cost of ownership argument, that you save money on development time and maintenance over the long run, is often true, but it depends on the project.
I should probably mention something that doesn't quite fit neatly into any of these sections but comes up often enough in conversations with clients that it's worth saying.
When to go composable
The approach makes most sense when a monolithic platform is actively getting in the way: when you need a custom frontend that the CMS can't deliver, when you're integrating multiple data sources, when performance is critical, or when you need the flexibility to evolve individual components independently. For a brochure site with five pages and a contact form, it's overkill.
If you're evaluating whether a composable approach is right for your next project, I'm happy to talk it through, reach out and I can look at your specific requirements.
Chris Ryan
Managing Director
17+ years in full-stack web development, most of it leading teams agency-side across e-commerce, CMS platforms, and bespoke applications. Specialises in infrastructure, system integration, and data privacy, with hands-on experience as a Data Protection Officer. Founded Innatus Digital in 2020 to offer the kind of honest, technically-led partnership that he felt was missing from the agency world.