Your first API key

What an API key is

An API key is a long password that lets Rectoly use an AI company's computers for you. You sign up with the company in your own name, and the company gives you the key. You pay the company for what you use; Rectoly gets no part of it.

You need one only when Rectoly's AI cannot run on your device. Normally translation, paper cards and Organize with AI run on the device itself (This device), and nothing is sent anywhere. That needs a device with plenty of memory (What you need). On a device without it, or when you would rather use a company's AI, an API key is the way.

Getting a key takes about ten minutes:

1. Choose an AI company.
2. Make an account with it, and add credit if it asks for money in advance.
3. Create a key and copy it.
4. Paste it into Rectoly.

Which company to choose

In Rectoly, one company is already chosen and marked (recommended): DeepSeek in mainland China or when Rectoly is in Simplified Chinese, OpenAI everywhere else. Google Gemini comes next in the list. Any of these three works.

OpenAI

The company behind ChatGPT. You pay in advance, from US$5, with a payment method such as a credit card. Get an OpenAI API key

Google Gemini

Google's AI. It has a free tier that needs no payment, with a daily limit, but on the free tier Google may use what you send (see below). You must be 18 or older. Get a Google Gemini API key

DeepSeek

A Chinese AI company with low prices. You pay in advance. Get a DeepSeek API key

• Each company serves only some countries and regions. OpenAI and Google Gemini, for example, are not offered in mainland China, Hong Kong or Russia: OpenAI's list, Google's list.
• Rectoly also works with Anthropic (Claude), OpenRouter and others. See Set up your own API key.
• In some regions and stores, Settings has no AI. An API key cannot be used there.

Three things to know first

1. Age. Google requires you to be 18 or older to use the Gemini API. OpenAI and DeepSeek ask anyone under 18 to have a parent's or guardian's consent. Read the company's terms when you sign up.
2. A ChatGPT subscription is not an API key. ChatGPT Plus and the other ChatGPT plans do not include the API, even when you pay for them. The API is a separate sign-up, paid with prepaid credit and a payment method such as a credit card (OpenAI).
3. Gemini's free tier uses your text. On the free tier, Google may use what you send to improve its products, and people at Google may read it. On the paid tier it does not. In the European Economic Area, Switzerland and the United Kingdom, Google treats free use like paid use (Gemini API terms). Most of what Rectoly sends is published papers, but do not use the free tier for a manuscript under review or anything confidential.

Paste the key into Rectoly

1. Open Settings and choose AI.
2. Under Where AI runs, choose Your own API key.
3. A notice appears: Your text will be sent to an external cloud. Read it, and if you agree, press Agree and set up.
4. Under Quick setup, look at AI company. Change it to the company your key comes from.
5. If you have no key yet, press Get a key. The company's key page opens. Create a key there and copy it (the company pages above show how), then come back to Rectoly.
6. Press Paste and check. Rectoly pastes the key you copied, saves it, checks the connection and starts using it.
7. When In use: appears with the company and the model, you are done. Translation, paper cards and Organize with AI now run with that company.

• If pasting is not allowed, press Paste and check again and allow it. Or type the key in the API key field and press Use this setup.
• Rectoly chooses the model for you. To choose another, open Advanced settings.
• The key is kept on this device only. On your other devices, paste it again.

What it costs

AI companies charge by the amount of text, counted in tokens (in English, a token is about four letters). Rectoly shows how many tokens a job uses, as "units of text", but never a price. The amounts below are our estimates from the companies' prices on 2026-10-23, for the models Rectoly chooses.

• With OpenAI, US$5 of credit translates about a hundred whole papers. A longer paper costs more; translating only part of one costs less.
• Paying in advance keeps the bill in check. OpenAI and DeepSeek take your money first and stop when it runs out, so you spend about what you put in. (OpenAI may let a request run a little past zero and take it from your next top-up.) OpenAI turns on automatic top-up when you first add credit; turn it off unless you want it.
• Gemini's free tier costs nothing. You pay only after you set up billing yourself.
• Prices change. The companies' pages are the authority: OpenAI, Google Gemini, DeepSeek.

What Rectoly sends

Only when you use an AI feature, and only what that feature needs, goes from this device straight to the company. It does not pass through Rectoly's servers.

• The paragraphs of the paper you are using: the ones you translate, and the ones a paper card is made from
• For translation, the paper's title, headings and opening (so terms stay consistent), and the text inside figures you translate
• With Organize with AI, the notes you organize

Nothing else is sent: not your PDF files, not your library, not your account details, and not papers you have not opened (unless you turn on cards for new papers yourself). The full list: What is sent.

Keep the key secret

Treat the key like a password. Anyone who has it can use the AI on your money.

• Do not post it on social media, in chats or in screenshots. Do not send it to anyone, Rectoly's support included; we never ask for it.
• If it may have leaked, delete it on the company's key page, create a new one, and paste the new one into Rectoly.
• Rectoly keeps the key on this device only, encrypted. It is not sent to Rectoly's servers and not synced to your other devices.

Stop using the key or delete it

• Stop using it in Rectoly: in Settings › AI, press Stop using. Rectoly goes back to This device and sends nothing more. To use the key again, choose Your own API key; the notice appears again.
• Make the key useless: delete it on the company's key page (OpenAI, Google Gemini, DeepSeek). A deleted key no longer works anywhere, Rectoly included. Do this when you stop for good, or when the key may have leaked.
• Rectoly has no button that erases only the saved key. Pasting a new key for the same company replaces it.

When something goes wrong