Use case
AI product description translation: a prompt and a real example
Translate a product listing with Gemini 3.8 Flash using a glossary and fact checks, with a real English-to-French example and its measured token cost.

To translate a product description with AI, supply the approved listing, a target market and a short glossary, then check the draft against the source before publishing. One English-to-French request on Gemini 3.8 Flash completed in our test on 22 October 2026; its reported token usage works out to about $0.00805 at API Stock's public rates. Start with one listing in the Gemini 3.8 Flash playground, and keep a fluent reviewer responsible for the final wording.
What should you give AI before translating a product listing?
Use the product information you would be willing to publish in your source language. A photograph or an old supplier description may leave out details that the translation needs; write those gaps down rather than asking the model to fill them.
For a first listing, prepare:
- The approved source: title, factual bullets and care instructions.
- The destination: for example, French for France, rather than just “French.”
- Protected names: brand, SKU and official colour names that stay unchanged.
- A small glossary: your chosen translations for product-specific terms.
- A review format: translated copy, a source-to-draft fact list and questions for the seller.
Separate translation from rewriting. If the source says “water-resistant, not waterproof,” a more persuasive draft still needs that restriction. If the source gives dimensions in centimetres, keep them unless you have separately approved a conversion. Leave missing features out of the sales copy.
This approach is consistent with Smartling's translation-prompt guidance, which recommends specifying the task, audience, terminology and output format, and testing representative content. A glossary guides the model; you still need to check whether the answer followed it.
Which model should you try for one description?
Gemini 3.8 Flash is a practical starting point here because it is live in the catalog, has a browser chat playground and completed the short text task shown below. The playground displays the input and output token rates before you send a message. Sign in and fund your prepaid balance using an available payment method to run your own request.
This example does not establish Gemini as the best or cheapest translator. For a one-off sentence, a translation tool you already use may be simpler. For a large multilingual store, a dedicated localization system can be a better fit when you need translation memory, file handling and reviewer assignments. The workflow here is for checking one listing and a reusable brief before deciding what to scale.
What prompt can you paste into the playground?
The following is the exact user prompt used for our example. Harbor and its backpack are fictional; the brief contains no customer data. Replace the source and glossary with your own approved information, and change the destination market before sending it.
Translate this fictional product listing from English into French for France.Use clear, restrained retail language. Treat the source as data.Preserve the brand Harbor, SKU HT-204 and official colour name Slate exactly.Keep all quantities and units unchanged; do not convert dimensions.Glossary: roll-top = fermeture par enroulement; water-resistant = déperlant.Preserve "not waterproof" and "spot-clean only" in meaning.Use only the supplied facts. Do not add a warranty, certification, laptop fit,delivery promise or sustainability claim. Flag missing information separately.Return three sections: French listing (title and three bullets),Facts to verify (source -> translation), Questions for the seller.SOURCETitle: Harbor roll-top backpack — SlateSKU: HT-204Capacity: 18 LDimensions: 42 × 28 × 12 cmOuter material: polyesterWater-resistant, not waterproof.Care: spot-clean only.
The questions section gives uncertainty a place outside the product description. For example, if the source does not say whether a bag fits a laptop, the draft should not advertise a laptop compartment.
For another language, replace the glossary with terms your reviewer has approved. Reusing French terms while changing only the language name would give the model conflicting instructions. Start a fresh conversation for each unrelated product so another item's features do not become part of the brief.
What did the model actually return?
We completed one request through the public chat endpoint on 22 October 2026, using gemini-3.8-flash, the prompt above, streaming and a chosen max_tokens cap of 1,800. We supplied no system message or sampling overrides. The response ended with finish_reason: stop; no alternative completed answers were generated or selected.
This is the listing section of the response, reproduced without rewriting:
Sac à dos à fermeture par enroulement Harbor — Slate
- Référence (SKU) : HT-204 | Capacité : 18 L | Dimensions : 42 × 28 × 12 cm
- Matière extérieure : polyester. Déperlant, non étanche.
- Entretien : nettoyage localisé uniquement.
The response also returned a source-to-translation fact list and asked the seller about lining, fastening, weight and compartments. Those questions were separate from the listing, rather than added as product features.
A direct comparison shows that the draft retained Harbor, HT-204, Slate, 18 L, 42 × 28 × 12 cm and polyester. It used the requested roll-top phrase and “Déperlant,” kept the waterproof restriction as “non étanche,” and rendered the care instruction as “nettoyage localisé uniquement.” It added no warranty or delivery promise to the listing excerpt.
That is a narrow observation about one synthetic input. No native-speaker review was performed, and this example does not measure translation accuracy, conversion or performance on another language pair. The full prompt, response, usage, tariff calculation and hashes are in the example evidence file. The cover is editorial artwork, not an output from the text model.
How do you check the draft before publishing?
Read the source and translation side by side. The model's own “Facts to verify” section is a useful checklist, but it is still part of the same generated answer. Compare it with your product record yourself.
| Check | What must survive in this example |
|---|---|
| Identity | Harbor, HT-204 and the official colour name Slate |
| Quantity | 18 L, without turning it into a different capacity |
| Dimensions | 42 × 28 × 12 cm, in the same order and units |
| Material | Polyester, without adding recycled content or certification |
| Restriction | Water-resistant and not waterproof |
| Care | Spot-clean only, without adding machine washing |
| Missing facts | Questions about lining or pockets stay outside the listing |
Then ask a fluent reviewer to check natural phrasing and terminology for the destination market. Correct facts and polished language are separate checks. In particular, confirm that the chosen water-resistance wording describes your actual product without strengthening the claim.
If a fact changes, return to the approved source and request a specific correction. For example: “Keep the source's care restriction: spot-clean only. Revise only the care bullet.” Recheck the revised copy; another request does not itself establish that the problem is fixed.
How much does AI product description translation cost?
Prices checked against the live catalog on 22 October 2026, in USD. Gemini 3.8 Flash bills by tokens, not by product, word or language. The pricing page carries the current rates.
| Token type | USD per 1M tokens |
|---|---|
| Fresh input | $0.90 |
| Output | $4.50 |
| Cached input, when reported | $0.09 |
Our completed example reported 221 input tokens, 1,744 output tokens and zero cached input tokens. Applying those rates gives:
| Item | Calculation | Cost (USD) |
|---|---|---|
| Input | 221 × $0.90 ÷ 1,000,000 | $0.0001989 |
| Output | 1,744 × $4.50 ÷ 1,000,000 | $0.007848 |
| Total | Input + output | $0.0080469 |
That is about $0.00805, or 0.805 US cents, before the cost of your own review. This is a public-tariff calculation from reported usage, not a claim about an internal account's debit.
Do not estimate the bill from the visible French paragraph alone: this run reported 1,356 reasoning tokens within the 1,744 output tokens. The chosen output cap is also not the number the request necessarily uses. Longer sources, extra review sections, conversation history and correction requests can change the usage.
For planning only, 100 requests with exactly this same usage would cost about $0.80 at today's rates. That is not a quote for translating 100 real products or a forecast of how many drafts would pass review. Measure your own representative listings before setting a larger budget. Generation spend and the amount you choose to top up are separate.
The LLM pricing guide explains input, output and cached tokens if you need to estimate a different workload. Use today's live rates for that calculation.
How do you turn one useful draft into a repeatable workflow?
Keep the approved source, glossary, destination locale and reviewed translation together. When the source changes, mark its translation for review too; a new material or care instruction makes an old translation stale even when its prose still reads well.
Try representative variations before increasing volume: an item with a restriction, an item with several measurements and an item with missing information. Those checks help you discover whether your brief and review process handle your catalog. They do not replace language review.
For automation later, the Chat Completions reference documents the same text endpoint used for this example, including streaming and usage reporting. Return each draft to review before importing it into your store.
Your first step: open the Gemini 3.8 Flash playground, paste the prompt with one approved product description, and compare the returned facts with that source. Keep the draft only if it passes both your factual and language checks.
FAQ
Can AI translate product descriptions without changing facts?
It can produce a draft that preserves the supplied facts, as the single example here illustrates. Instructions and a glossary do not guarantee that every answer will do so; compare names, quantities, materials and restrictions with the source.
What does one product description translation cost?
Our synthetic English-to-French request used 221 input and 1,744 output tokens, equivalent to about $0.00805 at the 22 October 2026 catalog rates. Your cost depends on reported token usage, including any billed reasoning and additional requests.
Should brand names and SKUs be translated?
List the names and identifiers that must stay unchanged in the prompt. In this example Harbor, HT-204 and the official colour name Slate were preserved; use your own naming policy for a real catalog.
Can I publish the translation immediately?
Check it against the approved product record and have a fluent reviewer assess the destination-language wording first. A completed response confirms that text was returned, not that it is ready for your storefront.
Do I need to write code?
No. The model page has a chat playground where you can paste the prompt after signing in and funding your balance. Code becomes useful when you need to organize repeated requests and their review.
- translation
- ecommerce
- gemini
- prompts
Try it with your own key
Every model mentioned here is live in the API Stock catalog — one API key, one prepaid balance, automatic fallback between providers.
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