Technical Specifications

Authentication

Required header:

x-flout-key: YOUR_FLOUT_CUSTOMER_KEY

This header is required for authorization and usage attribution. The proxy does not read customer keys from query parameters.

Optional tracking header:

x-flout-xref: YOUR_CUSTOMER_OR_PROJECT_REFERENCE

Use this optional reference to group proxy usage in reporting.

Engine Selection

Engine values are internal identifiers (example: gv2, mv3) and may evolve over time. Use values documented here.

Vendor is selected using the engine request header.

engine: gv2   → Google Translate
engine: mv3   → Microsoft Translator
engine: dl2   → DeepL Translator

The engine replaces vendor-specific routes. All other request structure remains identical to the vendor API.

Google Translate (via Proxy)

Endpoint

POST https://cacheproxy.flouttranslate.com

Headers

Content-Type: application/json
x-flout-key: YOUR_FLOUT_CUSTOMER_KEY
engine: gv2
x-goog-api-key: YOUR_GOOGLE_API_KEY

Body (identical to Google API)

{
  "q": ["Text one", "Text two"],
  "target": "de",
  "source": "en"
}

Response (identical to Google API)

{
  "data": {
    "translations": [
      { "translatedText": "Text eins" },
      { "translatedText": "Text zwei" }
    ]
  }
}

Microsoft Translator (via Proxy)

Endpoint

POST https://cacheproxy.flouttranslate.com?to=de&from=en

Headers

Content-Type: application/json
x-flout-key: YOUR_FLOUT_CUSTOMER_KEY
engine: mv3
Ocp-Apim-Subscription-Key: YOUR_MICROSOFT_KEY
Ocp-Apim-Subscription-Region: YOUR_REGION

Body (identical to Microsoft API)

[
  { "Text": "Text one" },
  { "Text": "Text two" }
]

Response (identical to Microsoft API)

[
  {
    "translations": [
      { "text": "Text eins", "to": "de" }
    ]
  },
  {
    "translations": [
      { "text": "Text zwei", "to": "de" }
    ]
  }
]

DeepL Translator (via Proxy)

Endpoint

POST https://cacheproxy.flouttranslate.com

Headers

Content-Type: application/json
x-flout-key: YOUR_FLOUT_CUSTOMER_KEY
engine: dl2
Authorization: DeepL-Auth-Key YOUR_DEEPL_API_KEY

DeepL credentials may also be supplied with DeepL-Auth-Key or x-deepl-api-key.

Body (DeepL API v2 format)

{
  "text": ["Text one", "Text two"],
  "target_lang": "DE",
  "source_lang": "EN"
}

Response (DeepL API v2 format)

{
  "translations": [
    {
      "detected_source_language": "EN",
      "text": "Text eins"
    },
    {
      "detected_source_language": "EN",
      "text": "Text zwei"
    }
  ]
}

cURL Examples

Google (engine: gv2)

curl -X POST "https://cacheproxy.flouttranslate.com" \
  -H "Content-Type: application/json" \
  -H "x-flout-key: YOUR_KEY" \
  -H "engine: gv2" \
  -H "x-goog-api-key: YOUR_GOOGLE_API_KEY" \
  --data '{
    "q": ["Hello world", "How are you?"],
    "target": "de",
    "source": "en"
  }'

Microsoft (engine: mv3)

curl -X POST "https://cacheproxy.flouttranslate.com?to=de&from=en" \
  -H "Content-Type: application/json" \
  -H "x-flout-key: YOUR_KEY" \
  -H "engine: mv3" \
  -H "Ocp-Apim-Subscription-Key: YOUR_MICROSOFT_KEY" \
  -H "Ocp-Apim-Subscription-Region: YOUR_REGION" \
  --data '[
    { "Text": "Hello world" },
    { "Text": "How are you?" }
  ]'

DeepL (engine: dl2)

curl -X POST "https://cacheproxy.flouttranslate.com" \
  -H "Content-Type: application/json" \
  -H "x-flout-key: YOUR_KEY" \
  -H "engine: dl2" \
  -H "Authorization: DeepL-Auth-Key YOUR_DEEPL_API_KEY" \
  --data '{
    "text": ["Hello world", "How are you?"],
    "target_lang": "DE",
    "source_lang": "EN"
  }'

JavaScript Examples

Google (engine: gv2)

const response = await fetch(
  "https://cacheproxy.flouttranslate.com",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-flout-key": "YOUR_KEY",
      "engine": "gv2",
      "x-goog-api-key": "YOUR_GOOGLE_API_KEY"
    },
    body: JSON.stringify({
      q: ["Hello world", "How are you?"],
      target: "de",
      source: "en"
    })
  }
);

const data = await response.json();
console.log(data);

Microsoft (engine: mv3)

const response = await fetch(
  "https://cacheproxy.flouttranslate.com?to=de&from=en",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-flout-key": "YOUR_KEY",
      "engine": "mv3",
      "Ocp-Apim-Subscription-Key": "YOUR_MICROSOFT_KEY",
      "Ocp-Apim-Subscription-Region": "YOUR_REGION"
    },
    body: JSON.stringify([
      { Text: "Hello world" },
      { Text: "How are you?" }
    ])
  }
);

const data = await response.json();
console.log(data);

DeepL (engine: dl2)

const response = await fetch(
  "https://cacheproxy.flouttranslate.com",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-flout-key": "YOUR_KEY",
      "engine": "dl2",
      "Authorization": "DeepL-Auth-Key YOUR_DEEPL_API_KEY"
    },
    body: JSON.stringify({
      text: ["Hello world", "How are you?"],
      target_lang: "DE",
      source_lang: "EN"
    })
  }
);

const data = await response.json();
console.log(data);

Privacy Notice & Legal Declaration - Translation Vendor API Credentials

By providing translation vendor API credentials to Flout Translate, you authorize Flout Translate to act as your agent for submitting translation requests to third-party translation providers on your behalf.

Flout Translate performs orchestration, caching, batching, and cost optimisation. Vendor services remain the property of their respective owners.

Flout Translate does not permanently or specifically store or persist your translation vendor API credentials. You provide those credentials on each call to the Flout Translate Proxy API and they are passed through to the translation vendor during the Flout back-end process if a translation is requested from the vendor. The credentials may persist in memory briefly during that process.