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Course/Connect & Automate

10 min · +130 XP

API Keys: What, Where, How

The full picture in five minutes — plus your first key, live.

By the end of this lesson

You'll know exactly what a key is, where it comes from, and how to hand it to Claude.

A key is your personal club card

When your tool 'orders from a service's menu', the service wants to know WHO is ordering — to count your usage, apply your limits, and shut the door if the card leaks. So it gives you an API key: a long string of letters and numbers that means 'this is me'. That's the entire mystery. It identifies you. Nothing more.

Where a key comes from — the universal recipe

  1. 1Log into the service's website (your normal account).
  2. 2Find the section called Settings → 'API', 'Developers' or 'Integrations' — every service hides it under one of these names.
  3. 3Click 'Create key' and copy the long string it shows you.
  4. 4That's it. You now hold the key in your clipboard.

How to hand it to Claude

  1. 1While building, Claude says 'I need the [service] API key' — paste it right into the chat, once.
  2. 2Claude stores it in a small settings file inside your project (so the tool can use it every time) — you never deal with it again. That file stays on your machine; if you ever share or publish the project folder, tell Claude first so it keeps the key out.
  3. 3Lost it? Don't search your chats — go back to the service and create a fresh one. Keys are free and infinite.

Try it live: a Telegram key in two minutes (free)

  1. 1Open Telegram and find the official @BotFather (a verified bot by Telegram itself).
  2. 2Send it: /newbot — it asks for a name, then gives you a long token. That token IS your API key.
  3. 3One step everyone misses: open your NEW bot's chat in Telegram and press START. Until you do, it cannot message you.
  4. 4Now tell Claude: 'here's my Telegram bot token: … — make my budget tool send me a message when I add an expense over 100'. (Claude may need your chat id — it'll tell you how to get it in one message.)
  5. 5Congratulations: your first real integration. Your tool can now text you.
ℹDo you need keys for your first builds? No.

Budget tracker, habit app, kids' game — zero keys. Keys appear only when your tool reaches OUT to a service. When that day comes, the recipe above covers ninety percent of services; for the rest, ask Claude: 'walk me through getting the key for X'.

!The two hard rules

A key is a password — never post it publicly, never screenshot it. (Leaked one, or just nervous? Go back to the service and delete/regenerate it — the old key dies instantly.) And never give an agent access to anything truly dangerous early on: your bank, your crypto, anything irreversible. Receipts and calendars — yes. Savings — no. One more habit: before wiring a paid service into anything that runs on a schedule, ask Claude 'does the free tier of X cover this?' Power, on a short leash, pointed at boring problems.

Quick check

What does an API key actually do?

EAEvgeny Arsentyev

Author

Evgeny Arsentyev

PhD · Chief Product Officer at a healthtech company