API access matters because it's how an AI agent you control can operate the software you pay for. A tool with a good API lets you describe the outcome you want and have the agent do the work inside the tool. A tool without one means you do that work by hand. I check for API access before buying anything now.
This post expands a 68-second video that goes live on September 22, 2026. The embed will be added here once it's published.
Key takeaways
- You don't need to understand APIs to benefit from them. I still couldn't define one precisely. I know what having one does for me.
- An API turns a tool into something your agent can operate. Instead of you clicking through the app, the agent does it and you judge the result.
- Openness is a spectrum. Two tools can both "have an API" and one exposes a fraction of what the other does. The gaps are where you end up doing manual work again.
- Check before you pay. If a tool you're evaluating has API access you can leverage, 99% of the time it will make you a lot more productive.
- Every tool in our stack passed this test. Scheduling, email, the content planner, the website: an agent can operate each one.
Do you know what an API is? I definitely could not explain it to you in technical terms. What I do know is that it's becoming ever more relevant in my life that the tools, software and apps I pay for have really good APIs. A friend and I talked about this yesterday, and I figured the idea was worth a video and a longer write-up.
What is an API, in simple terms?
An API is a way for one piece of software to operate another piece of software. Amazon's definition is that "APIs are mechanisms that enable two software components to communicate with each other using a set of definitions and protocols."
My simple-brain version: an API is the way an AI agent that I control can communicate with and operate the tool I'm trying to use. The app has buttons and menus for humans. The API is the equivalent set of buttons and menus for software. When a tool has one, an agent can press those buttons for me.
That's the whole idea. Everything else in this post is a consequence of it.
Why does API access matter if you run AI agents?
Because the API is the difference between an agent that can advise you and an agent that can do the work.
Without API access, an agent can write the caption, but you still open the app and paste it. It can draft the email, but you still log in and send it. The last step stays manual, and the last step is usually the one you put off.
With API access, you become the orchestrator of the agents. You say "do something like this in the tool" or "create that outcome inside the tool," and it happens. The better the API, the more open it is and the more functionality it exposes, the more you can hand over. So it's basically a way for software, or for agents, to operate software.
I wrote about one concrete case last week: how I schedule social media posts with Claude. That only works because the scheduler we use, Zernio, exposes everything through an API, so Claude can upload the video and set the time for 4 platforms from one sentence.
What's the difference between a good API and a bad one?
A good API exposes everything you can do in the app. A bad one exposes a subset, and the missing pieces are exactly where you end up doing manual work again.
Two real examples from our stack:
- Notion. Our whole content planner lives in Notion, and an agent can create cards, fill in captions and change statuses through Notion's connector. But when we wanted the agent to add a new option to a status field, it couldn't. That property type isn't editable through the interface software uses. Every time we need a new status, a human opens Notion and clicks.
- Kit (email). The agent can add subscribers, tag them and create broadcasts through Kit's API. It cannot edit a form or the confirmation email that a form sends. So the giveaway flow on our site is automated right up to the confirmation email, which I edit by hand.
Neither is a dealbreaker. Both are good tools with APIs that cover most of what we need. But you can feel the edges, and the edges are where your time goes.
When you evaluate a tool, ask a sharper question than "does it have an API?" Ask: can an agent do the three things I'll do in this tool most often?
How do you check if a tool has API access?
Look for a "Developers", "API" or "Integrations" link in the tool's footer or settings, and read what it lets you do, not just whether it exists.
- Find the docs. Most tools link "API" or "Developers" in the footer. If you can't find it in two minutes, that tells you something.
- Skim the list of endpoints. Each one is an action software can take. Match them against the actions you actually do in the tool.
- Check for an MCP server. More tools now ship one. MCP is described by its maintainers as "an open-source standard for connecting AI applications to external systems," like a USB-C port for AI apps. If a tool has an MCP server, Claude and similar agents can use it with almost no setup.
- Check the price of access. Some tools gate the API behind a higher plan or a separate fee. That's fine, as long as you know before you commit.
- Ask the agent. Paste the docs link into Claude and ask, "Can you do X, Y and Z with this?" It will tell you what's there and what isn't.
Do you need to understand how APIs work to use them?
No. You need to know what you want done, clearly enough to describe it. The agent handles the technical part.
This is what's so cool about the time we live in. You don't have to understand what something is, and you can still leverage it and make the most out of it. I've never written an API call by hand. I have described, in plain English, what I wanted a tool to do, and watched the agent write and run the code that does it.
What you do need is the skill I wrote about in the most valuable skill in the age of AI: saying clearly what you want built. The API is what makes that sentence executable.
Who this is for (and who it isn't for)
This is for anyone who already uses an AI agent for real work and pays for software: founders, marketers, small teams, agencies like ours. If you're about to sign up for a new tool, this is the extra five minutes that decides whether the tool joins your system or becomes another tab.
It isn't for someone who doesn't use agents yet. An API does nothing for you on its own. And it isn't an argument to drop a great tool because its API is thin. Notion and Kit both stay. It's an argument to know where the edges are before you build on it.
Common mistakes when picking tools for AI agents
- Treating "has an API" as a yes-or-no question. Coverage is what matters. Two tools with APIs can be worlds apart.
- Choosing by the human interface alone. The prettiest app can be the one your agent can't touch.
- Assuming the API matches the app. Features often ship in the app first and reach the API later, or never.
- Skipping the approval check. Some APIs require a review before you can use them fully. YouTube, for example, restricts uploads from unaudited projects to private.
- Not asking the agent first. It reads docs faster than you do. Let it tell you what the tool can do before you pay.
I'm super bullish on this as a filter. Start noticing the tools you're using. If they have API access that you can leverage, you'll be able to use the tool yourself and have your agents interact with it in a very effective way. That combination is what makes the current moment fascinating to me.
Frequently asked questions
What does API stand for?
Application Programming Interface. In plain terms, it's the set of controls a tool exposes so that other software, including an AI agent, can operate it.
Is an MCP server the same as an API?
Not quite. An API is the tool's general interface for software. An MCP server is a standardized layer, usually built on top of an API, that lets AI applications like Claude connect to the tool with little setup. A tool with an MCP server almost always has an API underneath.
Can an AI agent use a tool that has no API?
Sometimes, by driving the app's interface like a person would, but that's slower and breaks when the app changes its layout. For anything you do daily, a real API is far more reliable.
Do I need to pay extra for API access?
It depends on the tool. Some include it on every plan, some gate it behind a higher tier, some charge per use. Check before you commit, because it changes what the tool is worth to you.