The text-translation API currently consists of a single endpoint, `translate`, which is described below.
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openapi: 3.2.0
info:
title: DeepL API Documentation Translate Text API
description: 'The DeepL API provides programmatic access to DeepL’s language AI technology.
Note: this OpenAPI spec is embedded into our API documentation and has shortened descriptions.'
termsOfService: https://www.deepl.com/pro-license
contact:
name: DeepL - Contact us
url: https://www.deepl.com/contact-us
version: 3.13.0
servers:
- url: https://api.deepl.com
description: DeepL API Pro
- url: https://api-free.deepl.com
description: DeepL API Free
tags:
- name: TranslateText
description: The text-translation API currently consists of a single endpoint, `translate`, which is described below.
paths:
/v2/translate:
post:
tags:
- TranslateText
summary: Request Translation
operationId: translateText
description: 'Translate one or more text strings into a target language. Send multiple strings in a
single request, within the request size limit, and specify formatting, tag handling,
and customization options such as glossaries, style rules, and translation memories.'
parameters:
- $ref: '#/components/parameters/CustomReportingTag'
requestBody:
required: true
content:
application/json:
schema:
type: object
required:
- text
- target_lang
properties:
text:
description: 'Text to be translated. Only UTF-8-encoded plain text is supported. The parameter may be specified
many times in a single request, within the request size limit (128KiB). Translations are returned
in the same order as they are requested. Each text in the array is translated independently — texts
do not share context with each other.'
type: array
x-default:
- Hello, World!
items:
type: string
example: Hello, World!
source_lang:
$ref: '#/components/schemas/SourceLanguage'
target_lang:
$ref: '#/components/schemas/TargetLanguage'
x-default: DE
context:
$ref: '#/components/schemas/Context'
show_billed_characters:
$ref: '#/components/schemas/ShowBilledCharacters'
split_sentences:
$ref: '#/components/schemas/SplitSentencesOption'
preserve_formatting:
$ref: '#/components/schemas/PreserveFormattingOption'
formality:
$ref: '#/components/schemas/Formality'
model_type:
$ref: '#/components/schemas/ModelType'
glossary_id:
description: 'Specify the glossary to use for the translation. **Important:** This requires the `source_lang`
parameter to be set. The language pair of the glossary has to match the language pair of the
request.
Cannot be used together with `glossary_ids`.'
type: string
example: def3a26b-3e84-45b3-84ae-0c0aaf3525f7
glossary_ids:
description: 'Specify up to 5 glossaries to use for the translation, as an array of glossary IDs. Each glossary''s matching terms are applied to the translation.
**Important:** This requires the `source_lang` parameter to be set. Every listed glossary must contain a dictionary for the requested language pair.
Cannot be used together with `glossary_id`.'
type: array
maxItems: 5
items:
type: string
example: def3a26b-3e84-45b3-84ae-0c0aaf3525f7
style_id:
description: 'Specify the [style rule list](/docs/customize/using-style-rules) to use for the translation.
**Important:** The target language has to match the language of the style rule list. A list
created for a root language (for example `en`) applies to that language and all of its variants
(`EN-GB`, `EN-US`). A list created for a variant (for example `en-GB`) applies only when
`target_lang` is that variant.
All `model_type` values are supported.'
type: string
example: 7ff9bfd6-cd85-4190-8503-d6215a321519
translation_memory_id:
$ref: '#/components/schemas/TranslationMemoryId'
translation_memory_threshold:
$ref: '#/components/schemas/TranslationMemoryThreshold'
custom_instructions:
description: Specify a list of instructions to customize the translation behavior. Up to 10 custom instructions can be specified, each with a maximum of 300 characters.
type: array
items:
type: string
example: Use a friendly, diplomatic tone
tag_handling:
$ref: '#/components/schemas/TagHandlingOption'
tag_handling_version:
$ref: '#/components/schemas/TagHandlingVersionOption'
outline_detection:
$ref: '#/components/schemas/OutlineDetectionOption'
enable_beta_languages:
description: This parameter is maintained for backward compatibility and has no effect.
type: boolean
default: false
deprecated: true
non_splitting_tags:
description: Comma-separated list of XML tags which never split sentences.
type: array
items:
type: string
example: non_splitting_tag
splitting_tags:
description: Comma-separated list of XML tags which always cause splits.
type: array
items:
type: string
example: splitting_tag
ignore_tags:
description: Comma-separated list of XML tags that indicate text not to be translated.
type: array
items:
type: string
example: ignore_tag
application/x-www-form-urlencoded:
schema:
type: object
required:
- text
- target_lang
properties:
text:
description: Text to be translated. Only UTF-8-encoded plain text is supported. The parameter may be specified many times in a single request, within the request size limit (128KiB). Translations are returned in the same order as they are requested. Each text in the array is translated independently — texts do not share context with each other.
type: array
items:
type: string
example: Hello, World!
source_lang:
$ref: '#/components/schemas/SourceLanguage'
target_lang:
$ref: '#/components/schemas/TargetLanguage'
context:
$ref: '#/components/schemas/Context'
show_billed_characters:
$ref: '#/components/schemas/ShowBilledCharacters'
split_sentences:
$ref: '#/components/schemas/SplitSentencesOption'
preserve_formatting:
$ref: '#/components/schemas/PreserveFormattingOptionStr'
formality:
$ref: '#/components/schemas/Formality'
model_type:
$ref: '#/components/schemas/ModelType'
glossary_id:
description: 'Specify the glossary to use for the translation. **Important:** This requires the `source_lang`
parameter to be set. The language pair of the glossary has to match the language pair of the
request.
Cannot be used together with `glossary_ids`.'
type: string
example: def3a26b-3e84-45b3-84ae-0c0aaf3525f7
glossary_ids:
description: 'Comma-separated list of up to 5 glossary IDs to use for the translation. Each glossary''s matching terms are applied to the translation. May also be sent as a repeated parameter.
**Important:** This requires the `source_lang` parameter to be set. Every listed glossary must contain a dictionary for the requested language pair.
Cannot be used together with `glossary_id`.'
type: array
maxItems: 5
items:
type: string
example: def3a26b-3e84-45b3-84ae-0c0aaf3525f7
translation_memory_id:
$ref: '#/components/schemas/TranslationMemoryId'
translation_memory_threshold:
$ref: '#/components/schemas/TranslationMemoryThreshold'
tag_handling:
$ref: '#/components/schemas/TagHandlingOption'
outline_detection:
$ref: '#/components/schemas/OutlineDetectionOptionStr'
enable_beta_languages:
description: This parameter is maintained for backward compatibility and has no effect.
type: boolean
default: false
deprecated: true
non_splitting_tags:
description: Comma-separated list of XML tags which never split sentences.
type: array
items:
type: string
example: non_splitting_tag
splitting_tags:
description: Comma-separated list of XML tags which always cause splits.
type: array
items:
type: string
example: splitting_tag
ignore_tags:
description: Comma-separated list of XML tags that indicate text not to be translated.
type: array
items:
type: string
example: ignore_tag
encoding:
text:
style: form
explode: true
responses:
'200':
description: The translate function returns a JSON representation of the translations in the order the text parameters have been specified.
headers:
X-Trace-ID:
$ref: '#/components/headers/X-Trace-ID'
content:
application/json:
schema:
type: object
properties:
translations:
type: array
minItems: 1
items:
type: object
properties:
detected_source_language:
description: The language detected in the source text. It reflects the value of the `source_lang` parameter, when specified.
type: string
example: EN
text:
description: The translated text.
type: string
example: Hallo, Welt!
billed_characters:
description: Number of characters counted by DeepL for billing purposes. Only present if the show_billed_characters parameter is set to true.
type: integer
example: 42
model_type_used:
description: Indicates the translation model used. Only present if model_type parameter is included in the request.
type: string
example: quality_optimized
tag_handling_version:
description: The version of the tag handling algorithm used for the translation. Only present when the `tag_handling` parameter (`xml` or `html`) is set. If you don't specify `tag_handling_version`, this shows the default that was applied.
type: string
enum:
- v2
- v1
example: v2
'400':
$ref: '#/components/responses/BadRequest'
'403':
$ref: '#/components/responses/ForbiddenScoped'
'404':
$ref: '#/components/responses/NotFound'
'413':
$ref: '#/components/responses/PayloadTooLarge'
'414':
$ref: '#/components/responses/URITooLong'
'429':
$ref: '#/components/responses/TooManyRequests'
'456':
$ref: '#/components/responses/QuotaExceeded'
'500':
$ref: '#/components/responses/InternalServerError'
'504':
$ref: '#/components/responses/ServiceUnavailable'
'529':
$ref: '#/components/responses/TooManyRequests'
security:
- auth_header: []
components:
responses:
ForbiddenScoped:
description: Authorization failed. Please supply a valid `DeepL-Auth-Key` via the `Authorization` header. This error is also returned when the API key is scoped but does not include the scope required for this endpoint.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
QuotaExceeded:
description: Quota exceeded. The character limit has been reached.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
ServiceUnavailable:
description: Resource currently unavailable. Try again later.
content:
application/json:
schema:
oneOf:
- $ref: '#/components/schemas/ErrorResponse'
- $ref: '#/components/schemas/InfrastructureErrorResponse'
TooManyRequests:
description: Too many requests. Please wait and resend your request.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
InternalServerError:
description: Internal error.
content:
application/json:
schema:
oneOf:
- $ref: '#/components/schemas/ErrorResponse'
- $ref: '#/components/schemas/InfrastructureErrorResponse'
NotFound:
description: The requested resource could not be found.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
BadRequest:
description: Bad request. Please check error message and your parameters.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
URITooLong:
description: The request URL is too long. You can avoid this error by using a POST request instead of a GET request, and sending the parameters in the HTTP body.
content:
application/json:
schema:
oneOf:
- $ref: '#/components/schemas/ErrorResponse'
- $ref: '#/components/schemas/InfrastructureErrorResponse'
PayloadTooLarge:
description: The request size exceeds the limit.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
schemas:
TagHandlingOption:
description: "Sets which kind of tags should be handled. Options currently available:\n * `xml`\n * `html`"
type: string
enum:
- xml
- html
example: html
Formality:
description: "Sets whether the translated text should lean towards formal or informal language.\nThis feature is only available for certain target languages. Setting this parameter\nwith a target language that does not support formality will fail, unless one of the\n`prefer_...` options are used.\nPossible options are:\n * `default` (default)\n * `more` - for a more formal language\n * `less` - for a more informal language\n * `prefer_more` - for a more formal language if available, otherwise fallback to default formality\n * `prefer_less` - for a more informal language if available, otherwise fallback to default formality"
type: string
enum:
- default
- more
- less
- prefer_more
- prefer_less
default: default
example: prefer_more
InfrastructureErrorResponse:
description: 'Error body returned by DeepL''s edge infrastructure for failures that occur before a request reaches the API itself. The message is nested under `error`, unlike the application-level `ErrorResponse`. Clients that parse error bodies should handle both shapes.
'
type: object
required:
- error
properties:
error:
type: object
required:
- message
properties:
message:
type: string
description: A human-readable description of the error.
example: Bad Gateway.
PreserveFormattingOptionStr:
description: 'Sets whether the translation engine should respect the original formatting, even if it would usually
correct some aspects.'
type: string
enum:
- '0'
- '1'
default: '0'
SourceLanguage:
type: string
description: 'Language of the text to be translated. If this parameter is omitted, the API will attempt to
detect the language of the text and translate it.
For the full list of supported source languages, see [supported languages](https://developers.deepl.com/docs/getting-started/supported-languages) or query the [`GET /v3/languages` endpoint](https://developers.deepl.com/docs/languages/using-the-languages-api).'
example: EN
ErrorResponse:
type: object
required:
- message
properties:
message:
type: string
description: A human-readable description of the error.
code:
type: string
description: A machine-readable identifier for the error, when available. Clients should match on this value rather than on `message` when branching on error types.
example: invalid_content_type
PreserveFormattingOption:
description: 'Sets whether the translation engine should respect the original formatting, even if it would usually
correct some aspects.'
type: boolean
default: false
ShowBilledCharacters:
description: 'When true, the response will include the billed_characters parameter, giving the
number of characters from the request that will be counted by DeepL for billing purposes.'
type: boolean
TranslationMemoryId:
type: string
format: uuid
description: A unique ID assigned to a translation memory.
example: a74d88fb-ed2a-4943-a664-a4512398b994
TargetLanguage:
type: string
description: 'The language into which the text should be translated.
For the full list of supported target languages, see [supported languages](https://developers.deepl.com/docs/getting-started/supported-languages) or query the [`GET /v3/languages` endpoint](https://developers.deepl.com/docs/languages/using-the-languages-api).'
example: DE
TranslationMemoryThreshold:
type: integer
description: The minimum matching percentage required for a translation memory segment to be applied (recommended to be 75% or higher). A value below 50 is treated as 50.
minimum: 0
maximum: 100
default: 75
example: 75
TagHandlingVersionOption:
description: 'Sets which version of the tag handling algorithm should be used. Options currently available:
* `v1`: Traditional algorithm (currently the default, will become deprecated in the future).
* `v2`: Improved algorithm released in October 2025 (will become the default in the future).'
type: string
enum:
- v2
- v1
ModelType:
type: string
description: Specifies which DeepL model should be used for translation.
enum:
- quality_optimized
- prefer_quality_optimized
- latency_optimized
OutlineDetectionOptionStr:
description: 'Disable the automatic detection of XML structure by setting the `outline_detection` parameter
to `false` and selecting the tags that should be considered structure tags. This will split sentences
using the `splitting_tags` parameter.'
type: string
default: '1'
enum:
- '0'
- '1'
Context:
description: 'Additional context that can influence a translation but is not translated itself.
Characters included in the `context` parameter will not be counted toward billing.'
type: string
example: This is context.
SplitSentencesOption:
description: "Sets whether the translation engine should first split the input into sentences.\n\nPossible values are:\n * 0 - no splitting at all, whole input is treated as one sentence\n * 1 (default when tag_handling is not set to html) - splits on punctuation and on newlines\n * nonewlines (default when tag_handling=html) - splits on punctuation only, ignoring newlines"
type: string
enum:
- '0'
- '1'
- nonewlines
default: '1'
example: '1'
OutlineDetectionOption:
description: 'Disable the automatic detection of XML structure by setting the `outline_detection` parameter
to `false` and selecting the tags that should be considered structure tags. This will split sentences
using the `splitting_tags` parameter.'
type: boolean
default: true
headers:
X-Trace-ID:
description: A unique identifier for the request that can be included in bug reports to DeepL support.
schema:
type: string
example: 501c3d93cc0c4f11ae2f60a226c2f0f0
parameters:
CustomReportingTag:
name: X-DeepL-Reporting-Tag
in: header
required: false
description: 'An optional custom reporting tag used to attribute this request''s usage to a team, project, customer, or other category of your choosing. Values are limited to 100 characters. See [How to use custom reporting tags](/docs/learning-how-tos/examples-and-guides/how-to-use-custom-reporting-tags) for validation rules, naming guidance, and how to retrieve usage by tag.
'
schema:
type: string
maxLength: 100
example: team-billing
securitySchemes:
auth_header:
type: apiKey
description: 'Authentication with `Authorization` header and `DeepL-Auth-Key` authentication scheme. Example: `DeepL-Auth-Key <api-key>`
'
name: Authorization
in: header
x-default: 'DeepL-Auth-Key '
externalDocs:
description: DeepL Pro - Plans and pricing
url: https://www.deepl.com/pro#developer
x-hideTryItPanel: true
x-codeSamples: false
x-provenance:
method: harvested
publisher: DeepL
source: https://developers.deepl.com/api-reference/openapi.yaml
note: split by refine-openapis from the provider's own published document, verified by fetch (openapi/_original/*.fetch.json);
stamped by stamp-openapi-provenance.py (roadmap#793)