API key
How to get an API key
Content AI writes on your own Anthropic API key, so you pay the model provider directly for usage. You write your first article without a key and connect it before the next one. Creating an account, adding credit and creating a key takes about 10 minutes. Below are all the steps and a rough cost of one article.
As of 12 October 2026. Prices and button names in provider consoles may change.
01What you need
An Anthropic API key is required: it powers drafts, scores, the fact check and repurposing. An OpenAI key is needed only for images, voice-over and transcription, and an ElevenLabs key only for the better voice-over. You need a payment card to add credit with the provider. You open the provider account under the provider's own terms, which you accept yourself.
02An Anthropic key, step by step
Create an account in the Anthropic console
Go to platform.claude.com and sign up. The console is a separate account: a chat subscription with Anthropic does not include API access, and your Content AI account is separate too.
Add credit
The API is prepaid: each request is deducted from your balance. In the console, go to Settings, then Billing, and click “Buy credits”. A small amount is enough to start, for example $10. Under Anthropic's rules, credits are valid for one year from purchase and are non-refundable. Auto-reload is optional. If you turn it on, set the threshold and the top-up amount.
Create the key
Go to Settings, then API keys, and click “Create key”. Name the key “Content AI” and choose how long it stays valid. The console shows the full key only once, right after you create it. It starts with “sk-ant-”. Copy it straight away. A lost key cannot be shown again, you can only create a new one.
Set a spend limit
In Settings, under Billing, you will find “Spend limits”. Click “Set limit” and enter a monthly amount your account will not exceed. When usage reaches the limit, the provider pauses requests and Content AI shows a message that says what to do. You can raise or remove the limit in the same place.
Paste the key into Content AI
After you first sign in, the setup guide asks for the key. The “Check key” button checks it with the provider at no cost. Later you can change or remove it in account settings, in the “API keys” section. Only your browser keeps the key, in an encrypted cookie: for 30 days with “Remember on this device”, and on another device you paste it again. Details: the Security section on the home page.
03What one article costs
Roughly, on your Anthropic account (the provider bills in US dollars):
| What you do | Rough cost |
|---|---|
| An article of about 800 words with SEO and AIO scores and a fact check | $0.20-0.40 |
| An article of about 1,500 words with SEO and AIO scores and a fact check | $0.30-0.50 |
| Web search while writing (up to 5 searches) | add $0.10-0.35 |
| Self-review (the model scores and revises the finished draft) | add $0.10-0.30 |
So $10 of credit covers roughly 25-50 articles of about 800 words. You can see the estimated cost of each draft in the app, under History (next to each entry, with the total in the “Estimated cost on your keys” field), and the exact billing in the Anthropic console, under Usage.
How we calculated this
Rates from the Anthropic price list as of 12 October 2026: the writing model costs $4 per million input tokens and $20 per million output tokens, the helper model $2 and $10, and web search $10 per 1,000 searches. An article with SEO and AIO scores and a fact check takes 4 requests to the writing model: writing (about 8,000-11,000 input tokens with instructions and knowledge base passages, about 3,000-8,000 output tokens including the model's reasoning), two scores (about 3,000 input tokens each, with brief reasoning by the model) and the fact check (about 7,000-9,000 input tokens). With web search, the pages it finds also count as input tokens. Polish text uses more tokens than English, and longer knowledge base documents raise the input cost.
04OpenAI (optional): images, voice-over and transcription
At platform.openai.com, create an account, add funds under Billing and create a new key under API keys (“Create new secret key”). The key starts with “sk-”. You can set a spend limit under Limits. Before your first image, OpenAI may ask you to verify your organization. An image costs from about one cent to a few dozen cents, depending on quality and format. Current rates are in the OpenAI price list. The app shows an estimate after each image and recording.
05ElevenLabs (optional): a better voice-over
At elevenlabs.io, create an account and choose a plan that includes API access. You create the key in your profile settings, under API keys. ElevenLabs bills voice-over by the number of text characters within your plan. Current rates are in the ElevenLabs price list.
06Keeping your key safe
Create a separate key just for Content AI: when you stop using it, you can delete it without affecting other tools. Never send your key by email or chat. Nobody from Content AI will ever ask for it. If the key may have leaked, delete it in the provider console, create a new one and paste it into the app.
07Common problems
- Key rejected
- The key is wrong, deleted or expired. Create a new one in the provider console and paste it into the app.
- No credit with the provider
- Your balance has run out or a payment failed. Add credit under Billing in the provider console.
- Your spend limit was reached
- Requests were paused by the limit you set in the console. Raise it or wait for the new month.
- The provider's monthly account cap was reached
- Every Anthropic account has a spending cap that depends on its usage tier. You can request a higher tier in the console, under Limits (“Request tier increase”).
- Too many requests at once
- New provider accounts start with lower request limits, which grow with usage history. Wait a moment and try again.