---
title: "Rankers"
id: rankers
slug: "/rankers"
description: "Rankers are a group of components that order documents by given criteria. Their goal is to improve your document retrieval results."
---

# Rankers

Rankers are a group of components that order documents by given criteria. Their goal is to improve your document retrieval results.

| Ranker | Description |
| --- | --- |
| [AmazonBedrockRanker](rankers/amazonbedrockranker.mdx) | Ranks documents based on their similarity to the query using Amazon Bedrock models. |
| [CohereRanker](rankers/cohereranker.mdx) | Ranks documents based on their similarity to the query using Cohere rerank models. |
| [FastembedRanker](rankers/fastembedranker.mdx) | Ranks documents based on their similarity to the query using cross-encoder models supported by FastEmbed. |
| [HuggingFaceTEIRanker](rankers/huggingfaceteiranker.mdx) | Ranks documents based on their similarity to the query using a Text Embeddings Inference (TEI) API endpoint. |
| [JinaRanker](rankers/jinaranker.mdx) | Ranks documents based on their similarity to the query using Jina AI models. |
| [LostInTheMiddleRanker](rankers/lostinthemiddleranker.mdx) | Positions the most relevant documents at the beginning and at the end of the resulting list while placing the least relevant documents in the middle, based on a [research paper](https://arxiv.org/abs/2307.03172). |
| [MetaFieldRanker](rankers/metafieldranker.mdx) | A lightweight Ranker that orders documents based on a specific metadata field value. |
| [MetaFieldGroupingRanker](rankers/metafieldgroupingranker.mdx) | Reorders the documents by grouping them based on metadata keys. |
| [NvidiaRanker](rankers/nvidiaranker.mdx) | Ranks documents using large-language models from [NVIDIA NIMs](https://ai.nvidia.com) . |
| [PyversityRanker](rankers/pyversityranker.mdx) | Reranks documents by balancing relevance and diversity using pyversity's diversification algorithms. |
| [TransformersSimilarityRanker](rankers/transformerssimilarityranker.mdx) | A legacy version of [SentenceTransformersSimilarityRanker](rankers/sentencetransformerssimilarityranker.mdx). |
| [SentenceTransformersDiversityRanker](rankers/sentencetransformersdiversityranker.mdx) | A Diversity Ranker based on Sentence Transformers. |
| [SentenceTransformersSimilarityRanker](rankers/sentencetransformerssimilarityranker.mdx) | A model-based Ranker that orders documents based on their relevance to the query. It uses a cross-encoder model to produce query and document embeddings. It then compares the similarity of the query embedding to the document embeddings to produce a ranking with the most similar documents appearing first.  <br /> <br />It's a powerful Ranker that takes word order and syntax into account. You can use it to improve the initial ranking done by a weaker Retriever, but it's also more expensive computationally than the Rankers that don't use models. |
