> This page is for version v2 API (default). > For other versions, use one of these documentation indexes: > - v2 API (default): https://docs.cohere.com/v2/llms.txt > - v1 API: https://docs.cohere.com/v1/llms.txt > For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://docs.cohere.com/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.cohere.com/_mcp/server. # Rerank API (v2) POST https://api.cohere.com/v2/rerank Content-Type: application/json This endpoint takes in a query and a list of texts and produces an ordered array with each text assigned a relevance score. Reference: https://docs.cohere.com/reference/rerank ## Authentication - `Authorization` header (bearer token, required) — Bearer authentication of the form `Bearer `, where token is your auth token. ## Request ### Headers - `X-Client-Name` (string, optional) — The name of the project that is making the request. ### Body (application/json) This endpoint expects an object. - `model` (string, required) — The identifier of the model to use, eg `rerank-v3.5`. - `query` (string, required) — The search query - `documents` (list of string, required) — 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` (integer, optional) — 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` (integer, optional) — Defaults to `4096`. Long documents will be automatically truncated to the specified number of tokens. - `priority` (integer, optional, default: 0) — 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. ## Response ### 200 OK - `results` (list of V2RerankPostResponsesContentApplicationJsonSchemaResultsItems, required) — An ordered list of ranked documents - `id` (string, optional) - `meta` (ApiMeta, optional) ## Errors ### 400 Bad Request Error This error is returned when the request is not well formed. This could be because: - JSON is invalid - The request is missing required fields - The request contains an invalid combination of fields - `message` (string, optional) - `id` (string, optional) ### 401 Unauthorized Error This error indicates that the operation attempted to be performed is not allowed. This could be because: - The api token is invalid - The user does not have the necessary permissions - `message` (string, optional) - `id` (string, optional) ### 403 Forbidden Error This error indicates that the operation attempted to be performed is not allowed. This could be because: - The api token is invalid - The user does not have the necessary permissions - `message` (string, optional) - `id` (string, optional) ### 404 Not Found Error This error is returned when a resource is not found. This could be because: - The endpoint does not exist - The resource does not exist eg model id, dataset id - `message` (string, optional) - `id` (string, optional) ### 422 Unprocessable Entity Error This error is returned when the request is not well formed. This could be because: - JSON is invalid - The request is missing required fields - The request contains an invalid combination of fields - `message` (string, optional) - `id` (string, optional) ### 429 Too Many Requests Error Too many requests - `message` (string, optional) - `id` (string, optional) ### 498 Invalid Token Error This error is returned when a request or response contains a deny-listed token. - `message` (string, optional) - `id` (string, optional) ### 499 Client Closed Request Error This error is returned when a request is cancelled by the user. - `message` (string, optional) - `id` (string, optional) ### 500 Internal Server Error This error is returned when an uncategorised internal server error occurs. - `message` (string, optional) - `id` (string, optional) ### 501 Not Implemented Error This error is returned when the requested feature is not implemented. - `message` (string, optional) - `id` (string, optional) ### 503 Service Unavailable Error This error is returned when the service is unavailable. This could be due to: - Too many users trying to access the service at the same time - `message` (string, optional) - `id` (string, optional) ### 504 Gateway Timeout Error This error is returned when a request to the server times out. This could be due to: - An internal services taking too long to respond - `message` (string, optional) - `id` (string, optional) ## Types ### V2RerankPostResponsesContentApplicationJsonSchemaResultsItems - `index` (integer, required) — 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` (double, required) — 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 ### ApiMeta - `api_version` (ApiMetaApiVersion, optional) - `billed_units` (ApiMetaBilledUnits, optional) - `tokens` (ApiMetaTokens, optional) - `cached_tokens` (double, optional) — The number of prompt tokens that hit the inference cache. - `warnings` (list of string, optional) ### ApiMetaApiVersion - `version` (string, required) - `is_deprecated` (boolean, optional) - `is_experimental` (boolean, optional) ### ApiMetaBilledUnits - `images` (double, optional) — The number of billed images. - `input_tokens` (double, optional) — The number of billed input tokens. - `image_tokens` (double, optional) — The number of billed image tokens. - `output_tokens` (double, optional) — The number of billed output tokens. - `search_units` (double, optional) — The number of billed search units. - `classifications` (double, optional) — The number of billed classifications units. - `pages` (double, optional) — The number of billed pages parsed. ### ApiMetaTokens - `input_tokens` (double, optional) — The number of tokens used as input to the model. - `output_tokens` (double, optional) — The number of tokens produced by the model. ## Examples **Request** ```json { "model": "rerank-v4.0-pro", "query": "What is the capital of the United States?", "documents": [ "Carson City is the capital city of the American state of Nevada.", "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.", "Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.", "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.", "Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states." ], "top_n": 3 } ``` **Response** ```json { "results": [ { "index": 3, "relevance_score": 0.999071 }, { "index": 4, "relevance_score": 0.7867867 }, { "index": 0, "relevance_score": 0.32713068 } ], "id": "07734bd2-2473-4f07-94e1-0d9f0e6843cf", "meta": { "api_version": { "version": "2", "is_experimental": false }, "billed_units": { "search_units": 1 } } } ``` **SDK Code** ```typescript Cohere TypeScript SDK import { CohereClient } from 'cohere-ai'; const cohere = new CohereClient({}); (async () => { const rerank = await cohere.v2.rerank({ documents: [ 'Carson City is the capital city of the American state of Nevada.', 'The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.', 'Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.', 'Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.', 'Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states.', ], query: 'What is the capital of the United States?', topN: 3, model: 'rerank-v4.0-pro', }); console.log(rerank); })(); ``` ```python Sync import cohere co = cohere.ClientV2() docs = [ "Carson City is the capital city of the American state of Nevada.", "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.", "Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.", "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.", "Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states.", ] response = co.rerank( model="rerank-v4.0-pro", query="What is the capital of the United States?", documents=docs, top_n=3, ) print(response) ``` ```python Async import cohere import asyncio co = cohere.AsyncClientV2() async def main(): response = await co.rerank( model="rerank-v4.0-pro", query="What is the capital of the United States?", documents=[ "Carson City is the capital city of the American state of Nevada.", "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.", "Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.", "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.", "Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states.", ], top_n=3 ) print(response) asyncio.run(main()) ``` ```java Cohere java SDK /* (C)2024 */ import com.cohere.api.Cohere; import com.cohere.api.resources.v2.requests.V2RerankRequest; import com.cohere.api.resources.v2.types.V2RerankResponse; import java.util.List; public class RerankV2Post { public static void main(String[] args) { Cohere cohere = Cohere.builder().clientName("snippet").build(); V2RerankResponse response = cohere .v2() .rerank( V2RerankRequest.builder() .model("rerank-v4.0-pro") .query("What is the capital of the United States?") .documents( List.of( "Carson City is the capital city of the American state of Nevada.", "The Commonwealth of the Northern Mariana Islands is a group of islands" + " in the Pacific Ocean. Its capital is Saipan.", "Capitalization or capitalisation in English grammar is the use of a" + " capital letter at the start of a word. English usage varies" + " from capitalization in other languages.", "Washington, D.C. (also known as simply Washington or D.C., and" + " officially as the District of Columbia) is the capital of the" + " United States. It is a federal district.", "Capital punishment has existed in the United States since before the" + " United States was a country. As of 2017, capital punishment is" + " legal in 30 of the 50 states.")) .topN(3) .build()); System.out.println(response); } } ``` ```go package main import ( "fmt" "strings" "net/http" "io" ) func main() { url := "https://api.cohere.com/v2/rerank" payload := strings.NewReader("{\n \"model\": \"rerank-v4.0-pro\",\n \"query\": \"What is the capital of the United States?\",\n \"documents\": [\n \"Carson City is the capital city of the American state of Nevada.\",\n \"The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.\",\n \"Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.\",\n \"Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.\",\n \"Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states.\"\n ],\n \"top_n\": 3\n}") req, _ := http.NewRequest("POST", url, payload) req.Header.Add("Authorization", "Bearer ") req.Header.Add("Content-Type", "application/json") res, _ := http.DefaultClient.Do(req) defer res.Body.Close() body, _ := io.ReadAll(res.Body) fmt.Println(res) fmt.Println(string(body)) } ``` ```ruby require 'uri' require 'net/http' url = URI("https://api.cohere.com/v2/rerank") http = Net::HTTP.new(url.host, url.port) http.use_ssl = true request = Net::HTTP::Post.new(url) request["Authorization"] = 'Bearer ' request["Content-Type"] = 'application/json' request.body = "{\n \"model\": \"rerank-v4.0-pro\",\n \"query\": \"What is the capital of the United States?\",\n \"documents\": [\n \"Carson City is the capital city of the American state of Nevada.\",\n \"The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.\",\n \"Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.\",\n \"Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.\",\n \"Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states.\"\n ],\n \"top_n\": 3\n}" response = http.request(request) puts response.read_body ``` ```php request('POST', 'https://api.cohere.com/v2/rerank', [ 'body' => '{ "model": "rerank-v4.0-pro", "query": "What is the capital of the United States?", "documents": [ "Carson City is the capital city of the American state of Nevada.", "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.", "Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.", "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.", "Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states." ], "top_n": 3 }', 'headers' => [ 'Authorization' => 'Bearer ', 'Content-Type' => 'application/json', ], ]); echo $response->getBody(); ``` ```csharp using RestSharp; var client = new RestClient("https://api.cohere.com/v2/rerank"); var request = new RestRequest(Method.POST); request.AddHeader("Authorization", "Bearer "); request.AddHeader("Content-Type", "application/json"); request.AddParameter("application/json", "{\n \"model\": \"rerank-v4.0-pro\",\n \"query\": \"What is the capital of the United States?\",\n \"documents\": [\n \"Carson City is the capital city of the American state of Nevada.\",\n \"The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.\",\n \"Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.\",\n \"Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.\",\n \"Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states.\"\n ],\n \"top_n\": 3\n}", ParameterType.RequestBody); IRestResponse response = client.Execute(request); ``` ```swift import Foundation let headers = [ "Authorization": "Bearer ", "Content-Type": "application/json" ] let parameters = [ "model": "rerank-v4.0-pro", "query": "What is the capital of the United States?", "documents": ["Carson City is the capital city of the American state of Nevada.", "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.", "Capitalization or capitalisation in English grammar is the use of a capital letter at the start of a word. English usage varies from capitalization in other languages.", "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.", "Capital punishment has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."], "top_n": 3 ] as [String : Any] let postData = JSONSerialization.data(withJSONObject: parameters, options: []) let request = NSMutableURLRequest(url: NSURL(string: "https://api.cohere.com/v2/rerank")! as URL, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0) request.httpMethod = "POST" request.allHTTPHeaderFields = headers request.httpBody = postData as Data let session = URLSession.shared let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in if (error != nil) { print(error as Any) } else { let httpResponse = response as? HTTPURLResponse print(httpResponse) } }) dataTask.resume() ```