The Cohere Rerank API takes a query and a list of text documents and returns them ordered by relevance with assigned relevance scores. It is commonly used as a second-stage ranker in retrieval-augmented generation pipelines to improve the quality of search results before passing them to a language model. The API supports multilingual reranking and can significantly improve the precision of search and retrieval systems.
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openapi: 3.2.0
info:
title: Cohere Rerank API
version: 1.0.0
servers:
- url: https://api.cohere.com
description: production
tags:
- name: Rerank
paths:
/v2/rerank:
post:
operationId: v2_rerank
summary: Rerank API (v2)
description: This endpoint takes in a query and a list of texts and produces an ordered array with each text assigned a relevance score.
tags:
- Rerank
parameters:
- name: X-Client-Name
in: header
description: 'The name of the project that is making the request.
'
required: false
schema:
type: string
responses:
'200':
description: OK
content:
application/json:
schema:
$ref: '#/components/schemas/v2_rerank_Response_200'
'400':
description: "This error is returned when the request is not well formed. This could be because:\n - JSON is invalid\n - The request is missing required fields\n - The request contains an invalid combination of fields\n"
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestBadRequestError'
'401':
description: "This error indicates that the operation attempted to be performed is not allowed. This could be because:\n - The api token is invalid\n - The user does not have the necessary permissions\n"
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestUnauthorizedError'
'403':
description: "This error indicates that the operation attempted to be performed is not allowed. This could be because:\n - The api token is invalid\n - The user does not have the necessary permissions\n"
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestForbiddenError'
'404':
description: "This error is returned when a resource is not found. This could be because:\n - The endpoint does not exist\n - The resource does not exist eg model id, dataset id\n"
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestNotFoundError'
'422':
description: "This error is returned when the request is not well formed. This could be because:\n - JSON is invalid\n - The request is missing required fields\n - The request contains an invalid combination of fields\n"
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestUnprocessableEntityError'
'429':
description: Too many requests
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestTooManyRequestsError'
'498':
description: 'This error is returned when a request or response contains a deny-listed token.
'
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestInvalidTokenError'
'499':
description: 'This error is returned when a request is cancelled by the user.
'
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestClientClosedRequestError'
'500':
description: 'This error is returned when an uncategorised internal server error occurs.
'
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestInternalServerError'
'501':
description: 'This error is returned when the requested feature is not implemented.
'
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestNotImplementedError'
'503':
description: "This error is returned when the service is unavailable. This could be due to:\n - Too many users trying to access the service at the same time\n"
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestServiceUnavailableError'
'504':
description: "This error is returned when a request to the server times out. This could be due to:\n - An internal services taking too long to respond\n"
content:
application/json:
schema:
$ref: '#/components/schemas/Rerankv2RequestGatewayTimeoutError'
requestBody:
description: ''
content:
application/json:
schema:
type: object
properties:
model:
type: string
description: The identifier of the model to use, eg `rerank-v3.5`.
query:
type: string
description: The search query
documents:
type: array
items:
type: string
description: 'A list of texts that will be compared to the `query`.
For optimal performance we recommend against sending more than 1,000 documents in a single request.
**Note**: long documents will automatically be truncated to the value of `max_tokens_per_doc`.
**Note**: structured data should be formatted as YAML strings for best performance.'
top_n:
type: integer
minimum: 1
description: Limits the number of returned rerank results to the specified value. If not passed, all the rerank results will be returned.
max_tokens_per_doc:
type: integer
description: Defaults to `4096`. Long documents will be automatically truncated to the specified number of tokens.
priority:
type: integer
minimum: 0
maximum: 999
default: 0
description: 'Controls how early the request is handled. Lower numbers indicate higher priority (default: 0, the highest). When the system is under load, higher-priority requests are processed first and are the least likely to be dropped.'
required:
- model
- query
- documents
security:
- bearerAuth: []
/v1/rerank:
post:
operationId: rerank
summary: Rerank API (v1)
description: This endpoint takes in a query and a list of texts and produces an ordered array with each text assigned a relevance score.
parameters:
- name: X-Client-Name
in: header
description: 'The name of the project that is making the request.
'
required: false
schema:
type: string
responses:
'200':
description: OK
content:
application/json:
schema:
$ref: '#/components/schemas/rerank_Response_200'
'400':
description: "This error is returned when the request is not well formed. This could be because:\n - JSON is invalid\n - The request is missing required fields\n - The request contains an invalid combination of fields\n"
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestBadRequestError'
'401':
description: "This error indicates that the operation attempted to be performed is not allowed. This could be because:\n - The api token is invalid\n - The user does not have the necessary permissions\n"
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestUnauthorizedError'
'403':
description: "This error indicates that the operation attempted to be performed is not allowed. This could be because:\n - The api token is invalid\n - The user does not have the necessary permissions\n"
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestForbiddenError'
'404':
description: "This error is returned when a resource is not found. This could be because:\n - The endpoint does not exist\n - The resource does not exist eg model id, dataset id\n"
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestNotFoundError'
'422':
description: "This error is returned when the request is not well formed. This could be because:\n - JSON is invalid\n - The request is missing required fields\n - The request contains an invalid combination of fields\n"
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestUnprocessableEntityError'
'429':
description: Too many requests
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestTooManyRequestsError'
'498':
description: 'This error is returned when a request or response contains a deny-listed token.
'
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestInvalidTokenError'
'499':
description: 'This error is returned when a request is cancelled by the user.
'
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestClientClosedRequestError'
'500':
description: 'This error is returned when an uncategorised internal server error occurs.
'
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestInternalServerError'
'501':
description: 'This error is returned when the requested feature is not implemented.
'
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestNotImplementedError'
'503':
description: "This error is returned when the service is unavailable. This could be due to:\n - Too many users trying to access the service at the same time\n"
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestServiceUnavailableError'
'504':
description: "This error is returned when a request to the server times out. This could be due to:\n - An internal services taking too long to respond\n"
content:
application/json:
schema:
$ref: '#/components/schemas/RerankRequestGatewayTimeoutError'
requestBody:
description: ''
content:
application/json:
schema:
type: object
properties:
model:
type: string
description: The identifier of the model to use, eg `rerank-v3.5`.
query:
type: string
description: The search query
documents:
type: array
items:
$ref: '#/components/schemas/V1RerankPostRequestBodyContentApplicationJsonSchemaDocumentsItems'
description: 'A list of document objects or strings to rerank.
If a document is provided the text fields is required and all other fields will be preserved in the response.
The total max chunks (length of documents * max_chunks_per_doc) must be less than 10000.
We recommend a maximum of 1,000 documents for optimal endpoint performance.'
top_n:
type: integer
minimum: 1
description: The number of most relevant documents or indices to return, defaults to the length of the documents
rank_fields:
type: array
items:
type: string
description: If a JSON object is provided, you can specify which keys you would like to have considered for reranking. The model will rerank based on order of the fields passed in (i.e. rank_fields=['title','author','text'] will rerank using the values in title, author, text sequentially. If the length of title, author, and text exceeds the context length of the model, the chunking will not re-consider earlier fields). If not provided, the model will use the default text field for ranking.
return_documents:
type: boolean
default: false
description: '- If false, returns results without the doc text - the api will return a list of {index, relevance score} where index is inferred from the list passed into the request.
- If true, returns results with the doc text passed in - the api will return an ordered list of {index, text, relevance score} where index + text refers to the list passed into the request.'
max_chunks_per_doc:
type: integer
default: 10
description: The maximum number of chunks to produce internally from a document
required:
- query
- documents
security:
- bearerAuth: []
tags:
- Rerank
components:
schemas:
rerank_Response_200:
type: object
properties:
id:
type: string
results:
type: array
items:
$ref: '#/components/schemas/V1RerankPostResponsesContentApplicationJsonSchemaResultsItems'
description: An ordered list of ranked documents
meta:
$ref: '#/components/schemas/ApiMeta'
required:
- results
title: rerank_Response_200
RerankRequestInvalidTokenError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestInvalidTokenError
RerankRequestUnauthorizedError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestUnauthorizedError
Rerankv2RequestInvalidTokenError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestInvalidTokenError
Rerankv2RequestNotImplementedError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestNotImplementedError
v2_rerank_Response_200:
type: object
properties:
id:
type: string
results:
type: array
items:
$ref: '#/components/schemas/V2RerankPostResponsesContentApplicationJsonSchemaResultsItems'
description: An ordered list of ranked documents
meta:
$ref: '#/components/schemas/ApiMeta'
required:
- results
title: v2_rerank_Response_200
RerankRequestBadRequestError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestBadRequestError
Rerankv2RequestBadRequestError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestBadRequestError
ApiMeta:
type: object
properties:
api_version:
$ref: '#/components/schemas/ApiMetaApiVersion'
billed_units:
$ref: '#/components/schemas/ApiMetaBilledUnits'
tokens:
$ref: '#/components/schemas/ApiMetaTokens'
cached_tokens:
type: number
format: double
description: 'The number of prompt tokens that hit the inference cache.
'
warnings:
type: array
items:
type: string
title: ApiMeta
RerankRequestForbiddenError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestForbiddenError
V1RerankPostResponsesContentApplicationJsonSchemaResultsItems:
type: object
properties:
document:
$ref: '#/components/schemas/RerankResponseResultsItemDocument'
description: If `return_documents` is set as `false` this will return none, if `true` it will return the documents passed in
index:
type: integer
description: Corresponds to the index in the original list of documents to which the ranked document belongs. (i.e. if the first value in the `results` object has an `index` value of 3, it means in the list of documents passed in, the document at `index=3` had the highest relevance)
relevance_score:
type: number
format: double
description: Relevance scores are normalized to be in the range `[0, 1]`. Scores close to `1` indicate a high relevance to the query, and scores closer to `0` indicate low relevance. It is not accurate to assume a score of 0.9 means the document is 2x more relevant than a document with a score of 0.45
required:
- index
- relevance_score
title: V1RerankPostResponsesContentApplicationJsonSchemaResultsItems
Rerankv2RequestForbiddenError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestForbiddenError
Rerankv2RequestUnprocessableEntityError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestUnprocessableEntityError
RerankRequestInternalServerError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestInternalServerError
Rerankv2RequestInternalServerError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestInternalServerError
V2RerankPostResponsesContentApplicationJsonSchemaResultsItems:
type: object
properties:
index:
type: integer
description: Corresponds to the index in the original list of documents to which the ranked document belongs. (i.e. if the first value in the `results` object has an `index` value of 3, it means in the list of documents passed in, the document at `index=3` had the highest relevance)
relevance_score:
type: number
format: double
description: Relevance scores are normalized to be in the range `[0, 1]`. Scores close to `1` indicate a high relevance to the query, and scores closer to `0` indicate low relevance. It is not accurate to assume a score of 0.9 means the document is 2x more relevant than a document with a score of 0.45
required:
- index
- relevance_score
title: V2RerankPostResponsesContentApplicationJsonSchemaResultsItems
Rerankv2RequestNotFoundError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestNotFoundError
RerankRequestNotImplementedError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestNotImplementedError
RerankRequestNotFoundError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestNotFoundError
Rerankv2RequestTooManyRequestsError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestTooManyRequestsError
Rerankv2RequestClientClosedRequestError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestClientClosedRequestError
ApiMetaApiVersion:
type: object
properties:
version:
type: string
is_deprecated:
type: boolean
is_experimental:
type: boolean
required:
- version
title: ApiMetaApiVersion
RerankResponseResultsItemDocument:
type: object
properties:
text:
type: string
description: The text of the document to rerank
required:
- text
description: If `return_documents` is set as `false` this will return none, if `true` it will return the documents passed in
title: RerankResponseResultsItemDocument
ApiMetaTokens:
type: object
properties:
input_tokens:
type: number
format: double
description: 'The number of tokens used as input to the model.
'
output_tokens:
type: number
format: double
description: 'The number of tokens produced by the model.
'
title: ApiMetaTokens
Rerankv2RequestServiceUnavailableError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestServiceUnavailableError
RerankRequestClientClosedRequestError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestClientClosedRequestError
RerankDocument:
type: object
additionalProperties:
type: string
title: RerankDocument
RerankRequestTooManyRequestsError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestTooManyRequestsError
Rerankv2RequestUnauthorizedError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestUnauthorizedError
RerankRequestUnprocessableEntityError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestUnprocessableEntityError
Rerankv2RequestGatewayTimeoutError:
type: object
properties:
message:
type: string
id:
type: string
title: Rerankv2RequestGatewayTimeoutError
RerankRequestServiceUnavailableError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestServiceUnavailableError
ApiMetaBilledUnits:
type: object
properties:
images:
type: number
format: double
description: 'The number of billed images.
'
input_tokens:
type: number
format: double
description: 'The number of billed input tokens.
'
image_tokens:
type: number
format: double
description: 'The number of billed image tokens.
'
output_tokens:
type: number
format: double
description: 'The number of billed output tokens.
'
search_units:
type: number
format: double
description: 'The number of billed search units.
'
classifications:
type: number
format: double
description: 'The number of billed classifications units.
'
pages:
type: number
format: double
description: 'The number of billed pages parsed.
'
title: ApiMetaBilledUnits
RerankRequestGatewayTimeoutError:
type: object
properties:
message:
type: string
id:
type: string
title: RerankRequestGatewayTimeoutError
V1RerankPostRequestBodyContentApplicationJsonSchemaDocumentsItems:
oneOf:
- type: string
- $ref: '#/components/schemas/RerankDocument'
title: V1RerankPostRequestBodyContentApplicationJsonSchemaDocumentsItems
securitySchemes:
bearerAuth:
type: http
scheme: bearer