✓ Checked against OpenAI's official pages on 23 September 2026. Screens and prices change: if something looks different, trust what OpenAI shows you.
An OpenAI API key is a secret code that lets TranslateRocket send your site’s text to OpenAI’s AI models (the same family behind ChatGPT) and get the translation back; you pay OpenAI directly, a little at a time.
📖 Words you will meet
- API key: a long secret code. Whoever has it can spend your credit, so treat it like a password.
- Credit: money you load in advance. Each translation takes a small amount from it.
- Token: the unit OpenAI charges by. Roughly, 1 token is about 4 characters of English text.
What you need before you start
- An email address (or a Google/Microsoft/Apple account) to create an OpenAI account.
- A mobile phone. OpenAI asks you to verify a phone number before you create your first key. The code arrives by SMS or, in some countries, WhatsApp. It cannot be sent by email or voice call.
- A payment card. New API accounts are prepaid: you buy credit first. The minimum purchase is $5 (the default amount offered is $10).
- About 10 minutes.
Important: a ChatGPT Plus or Pro subscription is a different product. It does not give you API credit.
Step by step
TranslateRocket – mysite.com. Leave the permissions on the default (All).Keep the key somewhere safe until you paste it into WordPress (a password manager is ideal). Do not send it by email or chat.
How much it costs
Official price (OpenAI pricing page, standard tier, checked 23 Sep 2026), per 1 million tokens:
| Model | Text you send (input) | Text you get back (output) |
|---|---|---|
| gpt-4o-mini (TranslateRocket’s default) | $0.15 | $0.60 |
| gpt-4.1-mini | $0.40 | $1.60 |
| gpt-4o | $2.50 | $10.00 |
| gpt-4.1 | $2.00 | $8.00 |
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 (4 characters per token).
- 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.
- With gpt-4o-mini: 30,000 × $0.15 / 1,000,000 + 30,000 × $0.60 / 1,000,000 ≈ $0.02. That is two cents.
- With gpt-4o: about $0.38.
So the $5 minimum would cover this example site many times over with gpt-4o-mini. This is an estimate: your real cost depends on how much text your pages have. Text that TranslateRocket has already translated is reused and not sent again.
Is there a free allowance? OpenAI’s documentation lists a “Free” usage tier, but it does not say clearly how much you can use without buying credit. Plan on buying the $5 minimum. Purchased credit expires after one year and is normally not refundable.
Safety (please read)
1. Set a spending limit at OpenAI.
- Go to https://platform.openai.com/settings/organization/limits
- In Spend, click Edit spend limit.
- Enter a Monthly spend limit, for example $5.
- Turn on Enforce a hard limit. Without this, OpenAI only sends you a warning email and keeps working.
- Click Save.
OpenAI says the limit is not instantaneous: spending can go slightly over before requests stop. With prepaid credit and auto-reload turned off, you can never lose more than the credit you loaded.
2. 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.
3. Never share the key. Do not put it in emails, chats, screenshots or support tickets. OpenAI’s terms do not allow sharing keys. If someone needs access, invite them to your OpenAI account instead.
4. If you think the key has leaked, delete it.
- Go to https://platform.openai.com/api-keys
- Click the trash can icon next to the key. A deleted key stops working at once.
- Create a new key and paste it into TranslateRocket.
- Check https://platform.openai.com/settings/organization/usage for spending 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 OpenAI.
- Paste your key into the API key field.
- At the top of the box, set Active provider to OpenAI.
- Optional: the Model field can stay empty (TranslateRocket then uses gpt-4o-mini). 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 |
|---|---|---|
| “Incorrect API key provided” or “Invalid Authentication” (401) | The key was copied wrongly (a missing letter, an extra space) or it was deleted. | Paste it again carefully. If you no longer have it, create a new key: old keys cannot be shown again. |
| “Credit balance exhausted” (429) | Your prepaid credit ran out. | Open https://platform.openai.com/settings/organization/billing and click Buy credits (or Add to credit balance). Wait a few minutes, then try again. |
| “Organization spend limit reached” or “Project spend limit reached” (429) | Your own spend limit did its job. | Raise the limit in Settings → Limits, or wait for the next month. |
Other tips: if translation stops with “Rate limit reached”, wait a minute and try again, as OpenAI limits how fast you can send requests. If TranslateRocket says the model does not exist, click Load available models and pick one from the list.
Questions people ask
Is the OpenAI API free?
Not really. OpenAI does not clearly document a free allowance: new API accounts are prepaid and the minimum purchase is $5. With gpt-4o-mini, translating a 20-page site into one language costs about $0.02.
Does ChatGPT Plus include an API key?
No. ChatGPT Plus and Pro are a different product and do not give you API credit. The API has its own billing at platform.openai.com.
I lost my OpenAI API key. Can I see it again?
No. OpenAI shows the full key only once, when you create it. Create a new key and delete the old one from the API keys page.
How do I stop OpenAI from charging more than I want?
Buy prepaid credit with auto-reload turned off, then set a monthly spend limit and turn on "Enforce a hard limit" in Settings → Limits. With prepaid credit and no auto-reload you can never spend more than you loaded.
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: Anthropic (Claude) · Google Gemini · DeepL · Google Cloud Translation · Which one should I choose?
