This app uses Anthropic's API to talk to Claude. You'll need your own API key — it takes about 5 minutes to set up. Your key stays on your device and is never shared with anyone.
An API key is like a password that lets apps connect to Claude on your behalf. Anthropic gives you one when you sign up. Whenever this app talks to Claude, it sends your key so Anthropic knows who to charge.
Important
Your Claude.ai Pro subscription (if you have one) does not include API access. They're billed separately. Don't worry — for casual chat use, API costs are tiny (cents per day).
Step 1 — Create an Anthropic account
1
Go to console.anthropic.com
This is the developer console (different from claude.ai). Use the link below — you can use the same email as your claude.ai account if you have one, or sign up fresh.
Open console.anthropic.com
2
Verify your email and phone
Anthropic requires email verification and phone number verification (SMS). This is one-time and just for security — it isn't a paid step.
Step 2 — Add credits to your account
Anthropic's API is pay-as-you-go. You add some prepaid credit, and it gets drawn down as you use the app. $5 typically lasts weeks for casual use.
3
Open Plans & Billing
In the console sidebar, click Settings → Plans & Billing.
Go to Billing
4
Buy credits
Click Buy Credits. The minimum is usually $5. Add your card details. If you're in Europe, leave the "Business tax ID" field blank unless you have a registered VAT number — VAT will be added (~19% in Germany) for individuals.
If the button is grayed out
Try a credit card instead of a debit card, leave the VAT field blank, and clear your browser cache. Mastercard Debit cards sometimes fail Stripe's silent risk check.
Click Create Key. Give it a name like "Claude iPhone App". A long string starting with sk-ant-api03-… appears.
7
Copy it right away
Copy the key immediately — Anthropic shows it only once. After you close the dialog, it's gone forever (you'd have to make a new one).
Step 4 — Paste it into the app
8
Go back to the Claude app
Return to this app's onboarding screen. Paste your key into the input field and tap Continue. The app stores it locally on your device only.
Open the app →
Understanding costs
Anthropic charges per token (chunks of text). Different models have different prices. Here's a rough guide:
Haiku 4.5$1 / $5 per 1M tokens (fastest, cheapest)
Sonnet 4.5$3 / $15 per 1M tokens (default, balanced)
Sonnet 4.6$3 / $15 per 1M tokens (current daily driver)
Opus 4.5–4.7$5–15 / $25–75 per 1M tokens (smartest)
In practice, a typical conversation costs less than 1 cent. A long technical session with thinking mode might cost $0.10–$0.20. You can monitor usage at console.anthropic.com/settings/usage.
Set a spending limit
You can set a hard monthly cap on your account in Billing → Limits. Recommended for peace of mind: set it to $10–20/month so you can't be surprised.
Privacy & security
What we store on the server: nothing.
This app's server is a simple proxy. Messages pass through but are never saved or logged.
What stays on your device:
Your API key, conversation history, memory, and profile notes — all stored in your phone's local storage. They never leave your device except to talk to Anthropic's API.
What Anthropic sees:
Your messages, sent to their API to generate responses. Anthropic's policy: API data is retained 30 days for abuse monitoring, then deleted. They don't train on API data.