SDK vs MCP Explained: What They Are, in Plain English

Someone in a Slack channel asks whether they should “use the SDK or MCP” for their automation, and the thread fills up with acronyms until everyone quietly gives up and books a call with a developer. Let’s not do that. By the end of this you’ll know exactly what each one is, using nothing scarier than a plug socket.

I’m Jack, a Zapier Silver Solutions Partner running automation builds out of Norwich, and I use both of these things weekly. They’re not rivals. They solve different problems, and once you see the difference it stays obvious.

First, the plain-English definitions

An SDK (Software Development Kit) is a toolbox a company gives developers so they can build software that talks to that company’s product. If you want your own app to send messages through, say, a payments provider, you install their SDK and it hands you ready-made tools to do it. It’s for building things.

MCP (Model Context Protocol) is newer and different. It’s a standard way to let an AI assistant — like Claude — actually use your tools and data on your behalf. Not write code that uses them: use them, live, in a conversation. It’s for connecting an AI to the things it needs to help you.

The plug socket analogy

Here’s the one that makes it stick. Think about electrical appliances.

An SDK is like the wiring kit inside the appliance. If you’re the manufacturer building a new kettle, you use the kit to wire it up correctly so it works with the mains. It’s powerful, it’s specific to what you’re building, and it assumes you know what you’re doing with a screwdriver. Developers love it because it gives them fine control. Nobody expects the person making a cup of tea to touch it.

MCP is like the plug socket on the wall. It’s a standard shape. Any appliance with the right plug can use any socket, no rewiring required. You don’t think about the wiring behind the wall — you just plug in the kettle, the toaster, the lamp, and they work. MCP is that standard socket, but for connecting an AI to your tools: once something “speaks MCP,” your AI can plug into it without a custom build each time.

So: the SDK builds the appliance. MCP is the socket that lets you plug the finished appliance in without an electrician. Different jobs entirely.

When you’d reach for an SDK

You (or more likely your developer) use an SDK when you’re building a piece of software that needs deep, custom, reliable access to another platform. A bespoke client portal that pulls live data from your CRM. A pricing engine that talks to your accounting system. Anything where you need total control and you’re shipping a product. It’s more work, and in return you get to shape exactly how it behaves.

When MCP is the right tool

You reach for MCP when you want an AI assistant to do things in your actual tools — read your calendar, create a task, pull a report, send a message — through conversation rather than code. It’s the difference between an AI that can only talk about your business and one that can act in it. If you’ve read my explainer on Zapier MCP, that’s exactly this: a socket that lets Claude reach thousands of apps through Zapier without anyone writing bespoke integrations.

Do they ever work together?

Constantly. Under the bonnet, an MCP connection is often built using an SDK — the socket itself was wired up with a toolbox. As a business owner you don’t need to care about that plumbing, in the same way you don’t need to know how your wall socket was installed to boil a kettle. You just need to know which one you’re asking for: are you building an appliance (SDK), or plugging one in (MCP)?

The honest take

If you’re a business owner rather than a developer, you will almost never touch an SDK directly — that’s your builder’s world. But MCP is worth understanding, because it’s the thing quietly turning AI assistants from clever chatbots into something that can actually run errands inside your business. That shift is the interesting bit, and it’s why I keep banging on about it.

Frequently asked questions

Is MCP replacing SDKs? No. They do different jobs. MCP often relies on SDKs underneath. The socket doesn’t replace the wiring — it sits on top of it and makes it usable.

Do I need to be technical to use MCP? To use it, increasingly no — tools like Zapier MCP are built so a non-developer can connect an AI to their apps. To build a custom MCP server, yes, that’s developer territory.

Which one is more secure? Neither is inherently safer — it depends how it’s set up. With MCP especially, because an AI is taking actions, you want approval gates and audit trails. I’ve written on giving MCP proper boundaries for exactly that reason.

Which should my business start with? Almost certainly MCP, via a tool like Zapier, because it gives you AI-that-does-things with no custom build. Reach for an SDK only when you’re commissioning bespoke software.

Almost done! When you’re ready, here are four ways I can help you:

1. Read it. A guide on how to use ClickUp and actually make it work for you.
2. Connect it. Let’s be LinkedIn pals. I make funny videos sometimes.
3. Workshop it. Book a 30-minute chat to talk processes and build a Miro together.
4. Go for it. Fill in my contact form — let’s talk ClickUp or Automations. Whatever tickles your pickle.

Wanna hear from the unfiltered version of me? Sign up to my newsletter. The Working Notes. 2 minute reads. Behind the scenes. Hopefully helpful. Maybe funny.