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✓ Checked against Google's official pages on 23 September 2026. Screens and prices change: if something looks different, trust what Google shows you.
A Gemini API key is a secret code that lets TranslateRocket send your site’s text to Gemini, Google’s AI model, and get the translation back; Google offers a free tier with limits, and a paid tier you top up in advance.
📖 Words you will meet
- API key: a long secret code. Whoever has it can use your quota (and your credit, if you pay), so treat it like a password.
- Google AI Studio: Google’s website where you create Gemini keys, at aistudio.google.com.
- Project: a container Google uses to group your keys and billing. AI Studio creates one for you.
- Free tier / paid tier: free tier = no card, no charges, but lower limits. Paid tier = you add a card and prepay credit.
- Token: the unit Google charges by. For Gemini, 1 token is about 4 characters.
What you need before you start
- A Google account (a Gmail address works).
- For the free tier: no card. New accounts start on the free tier.
- For the paid tier: a payment card, and a prepayment of at least $5 (or the same in your currency).
- About 5 minutes.
Before you choose the free tier: two honest warnings
- Your text may be used by Google. On the free tier, Google may use what you send to improve its products, and human reviewers may read it. Google’s terms say not to send sensitive, confidential or personal information. Your public web pages are usually not secret, but think about it if your site has private content. Exception: if you are in the European Economic Area, Switzerland or the United Kingdom, Google says the paid-tier data rules apply to you even on the free tier.
- Businesses in Europe or the UK: read this line in Google’s terms. Google’s terms say that when you make an “API Client” available to users in the EEA, Switzerland or the UK, you may use only the paid services. Whether translating your own website counts as that is a legal question we cannot answer for you. If you are unsure, set up billing (step 7 below) or ask your advisor.
Also, the free tier has rate limits (how many requests per minute and per day). Google does not publish fixed numbers on its documentation page; you see your own limits in AI Studio. Large sites may need several days, or the paid tier.
Step by step
That is all you need for the free tier. To move to the paid tier (higher limits, and your text is not used to improve Google’s products):
Good to know: since 28 May 2026 every new key made in AI Studio is a new, safer type (“auth key”). Google says it rejects older “standard” keys from September 2026. If you have an old Gemini key, create a new one.
How much it costs
Free tier: free of charge on the models Google offers for free, within your rate limits.
Paid tier — official price (Google’s Gemini API pricing page, checked 23 Sep 2026), per 1 million tokens:
| Model | Text you send (input) | Text you get back (output, including “thinking”) |
|---|---|---|
| Gemini 2.5 Flash-Lite | $0.10 | $0.40 |
| Gemini 3.5 Flash-Lite | $0.30 | $2.50 |
| Gemini 2.5 Flash | $0.30 | $2.50 |
TranslateRocket’s default model is gemini-flash-lite-latest, a name Google points to its latest Flash-Lite release. Google does not say on that page which release it is today, so check the price of the Flash-Lite model you see in AI Studio.
What that means for a small site. Our example: a site of 20 pages with about 600 words each (12,000 words, about 75,000 characters), translated into one language.
- 75,000 characters is about 19,000 tokens.
- TranslateRocket also sends short instructions with each batch, and translated text is often longer than English. To be safe we count 30,000 tokens in and 30,000 tokens out. Newer Gemini models can also “think” before answering, and Google bills that thinking as output, so the real figure may be higher.
- Free tier: $0.
- Paid, Gemini 2.5 Flash-Lite: 30,000 × $0.10 / 1,000,000 + 30,000 × $0.40 / 1,000,000 ≈ $0.02.
- Paid, Gemini 3.5 Flash-Lite: about $0.08.
Prepaid credit expires after 12 months and is non-refundable (except in the specific cases Google lists).
Safety (please read)
1. On the free tier you cannot be charged. Without billing set up, Google has no card to charge.
2. On the paid tier, set a spending cap.
- In AI Studio, open the Spend page.
- Under Monthly spend cap, click Edit spend cap.
- Enter a monthly amount, for example $5, and save.
Google marks this feature as experimental and warns that spending can go over the cap for about 10 minutes before it stops. If you turn on auto-reload, also set a Monthly Limit: AI Studio Billing page → Manage auto-reload → expand Monthly Limit → enter an amount → Save. With prepaid credit and auto-reload off, you can never lose more than the credit you loaded.
3. Set a limit inside TranslateRocket too. In TranslateRocket → AI Translation, section Usage & limits, fill in Daily character limit (for example 200000). When the limit is reached, AI translation stops until the next day. 0 means no limit.
4. Never share the key. Google says: treat it like a password. Do not put it in emails, chats, screenshots or support tickets.
5. If you think the key has leaked (Google’s own checklist):
- Create a new key in AI Studio and paste it into TranslateRocket.
- Disable or delete the old key in the Google Cloud console Credentials page: https://console.cloud.google.com/apis/credentials (select the project, then the key). A deleted key can be restored within 30 days if you deleted the wrong one.
- Check your usage in AI Studio (Dashboard → Usage) for activity you do not recognise.
Where to paste it in TranslateRocket
- In your WordPress dashboard, open TranslateRocket → AI Translation.
- In the Provider & keys box, find the card called Google Gemini.
- Paste your key into the API key field.
- At the top of the box, set Active provider to Google Gemini.
- Optional: the Model field can stay empty (TranslateRocket then uses gemini-flash-lite-latest). The Load available models button lists the models your key can use.
- Click Save AI settings at the bottom of the page.
The card now shows the Active badge. You can translate from the Translations screen, or page by page in the visual editor.
If something does not work
| What you see | What it usually means | What to do |
|---|---|---|
| An error about an invalid key, or HTTP 400/403 | The key was copied wrongly, or it is an old standard key Google no longer accepts, or it is marked Blocked in AI Studio. | Paste it again carefully. If it still fails, create a new key in AI Studio: new keys are the accepted type. |
429 RESOURCE_EXHAUSTED |
You sent too much, too fast: free-tier limits, or (paid tier) the spending-speed limit. Daily limits reset at midnight Pacific time. | Wait and try again later, translate fewer pages at once, or move to the paid tier. |
402 Payment Required |
Paid tier: your prepaid credit is at $0. All keys linked to that billing account stop together. | AI Studio Billing page → Buy credits. |
Questions people ask
Is the Gemini API key free?
Yes, there is a free tier with no card, with rate limits you see in Google AI Studio. On the free tier Google may use the text you send to improve its products; different rules apply in the EEA, Switzerland and the UK.
My old Gemini API key stopped working. Why?
Since 28 May 2026 new keys made in AI Studio are a new, safer type, and Google says it rejects the older "standard" keys from September 2026. Create a new key in AI Studio.
Is Gemini the same as Google Cloud Translation?
No. Gemini is Google's AI model, with keys from Google AI Studio. Google Cloud Translation is Google Translate's professional service, with keys from the Google Cloud console and billing required.
How much does the paid Gemini API cost?
The paid tier starts with a $5 prepayment. With the Flash-Lite models, a 20-page site in one language costs roughly $0.02 to $0.08.
Which one should I choose?
See our comparison page for a simple comparison of all five services, and for the free option that needs no key at all.
Other guides: OpenAI · Anthropic (Claude) · DeepL · Google Cloud Translation · Which one should I choose?
