Claude API Basics: Automating Without Coding
You understand how the API works and can set up integrations.
Why this lesson matters
So far you've used Claude by hand: you type a prompt, you get an answer. But what if you need to do the same task 100 times? Or you want Claude to automatically summarise emails as they come in? Or generate a report every morning?
Then you need the API. And the good news: you don't have to be a developer to understand how it works or to put it to use. With no-code tools like Zapier and Make you can build API workflows without a single line of code.
What is an API, in plain terms
An API (Application Programming Interface) is a way for programs to talk to each other. Compare it to a restaurant:
- You (the customer) are the program that wants something
- The waiter is the API, he takes your order and brings back the result
- The kitchen is Claude, that's where the work gets done
You don't need to know how the kitchen works. You only need to know how to order.
In technical terms:
- You send a request to a URL
- You get a response back
- The request contains your prompt, the response contains Claude's reply
Every time you use Claude.ai, an API call is made behind the scenes. The chat interface is simply a nice wrapper around the same API you can use yourself.
The Anthropic Messages API
The Anthropic API has one main endpoint: Messages. You send a message there and get Claude's answer back.
The URL:
https://api.anthropic.com/v1/messagesWhat you send along:
| Field | What it does | Example |
|---|---|---|
model | Which Claude model | claude-sonnet-5 |
max_tokens | Maximum length of the answer | 1024 |
messages | Your prompt/conversation | [{"role": "user", "content": "Hello"}] |
system | System instruction (optional) | "You are a customer service agent" |
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API key: your access pass
To use the API you need an API key. That's a unique code that proves you have permission.
Here's how to get one:
- 1Go to console.anthropic.com
- 2Create an account (or log in)
- 3Go to API Keys
- 4Click Create Key
- 5Copy the key and store it safely
Example key (not a real one): sk-ant-api03-xxxxxxxxxxxxxxxxxxxYour API key is like a password. Never share it in code that's public (such as GitHub), in emails, or in chat messages. Store it in a password manager or as an environment variable. If your key leaks, someone else can make API calls at your expense.
Python example: your first API call
Even if you don't know Python, it's useful to see what an API call looks like. It's surprisingly little code:
import anthropic
client = anthropic.Anthropic(
api_key="your-api-key-here"
)
message = client.messages.create(
model="claude-sonnet-5",
max_tokens=1024,
system="You are a helpful Dutch assistant.",
messages=[
{"role": "user", "content": "What are the three largest cities in the Netherlands?"}
]
)
print(message.content[0].text)That's it. 5 lines of actual code. You send a question, Claude answers.
Install the Anthropic Python library with pip install anthropic. The library takes care of all the technical details, authentication, error handling, response parsing. All you need to focus on is your prompt.
Without code: Zapier and Make
Don't fancy Python? No problem. With Zapier and Make (formerly Integromat) you can build Claude API workflows by clicking blocks together.
Example: automatic email summary
| Step | Tool | Action |
|---|---|---|
| 1 | Gmail (trigger) | New email received |
| 2 | Anthropic (action) | Send the email text to Claude with the prompt: "Summarise this email in 2 sentences" |
| 3 | Slack (action) | Post the summary in the #inbox channel |
Other ideas: a daily news digest via RSS + Claude + email, automatic translation of incoming documents, or classifying customer feedback.
Zapier and Make both have an Anthropic/Claude integration. You enter your API key, configure your prompt, and click the workflow together. No code required.
Costs and limits
The API works on a usage basis, you pay per token:
| Model | Input (per 1M tokens) | Output (per 1M tokens) |
|---|---|---|
| Claude Haiku 4.5 | $1.00 | $5.00 |
| Claude Sonnet 5 | $2.00 | $10.00 |
| Claude Opus 5 | $5.00 | $25.00 |
Prices as of June 2026. Anthropic adjusts them, so check the pricing page before you draw up a budget.
Take an email summary with roughly 2,000 tokens in and 300 out. With Sonnet that's about 0.7 cents per summary, and at 50 a day you end up around 10 dollars a month. That's an estimate; your emails are longer or shorter.
Start with Haiku for simple work like classifying and labelling. Use Sonnet for analyses and writing. Opus when quality weighs heavier than cost. Most business applications run fine on Sonnet.
Practice exercise
- 1Create a free account at console.anthropic.com and generate an API key
- 2Pick a route:
- With code: Install the Python library and run the example above
- Without code: Create a Zapier account and build a workflow that summarises emails
- 1Experiment with different prompts and models
What is an API in the context of AI tools?
Which tool can you use to build Claude API workflows without code?
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