Output

Define what your pipeline returns. The Output component is the exit point of a pipeline. It declares which named outputs the pipeline exposes, such as retrieved documents, generated messages, or structured answers.

Every pipeline should have at least one output.

Key Features

• Defines the final output of the pipeline.
• Each named output maps to exactly one component connection.
• Supports standard output types: documents, messages, answers, and files.

Configuration

1. Drag the Output component onto the canvas from the Input & Output group in the Component Library.
2. Click the component card to add an input slot for each value your pipeline should return.
3. Connect the upstream component socket that produces the output to the corresponding slot.

Possible Outputs

You can use any of the following standard keys or define your own:

Output Key	Type	Description
documents	List[Document]	Retrieved or processed documents. Typically comes from a retriever or ranker.
messages	List[ChatMessage]	LLM-generated responses in chat format. Typically comes from an LLM or ChatGenerator. Use last_message for a single message or messages for the full conversation.
answers	List[Answer]	Structured answer objects from extractive or generative QA components (for example, ExtractiveReader or AnswerBuilder).
custom	Any	Any name that maps to the output socket of a component. Useful for returning file references, metadata, or other custom payloads.

Usage Examples

Document Search Pipeline

For a pipeline that returns retrieved documents, add documents to the Output component card and connect it to the component that should produce the documents. Here is an example:

# haystack-pipeline
components:
  query_embedder:
    type: deepset_cloud_custom_nodes.embedders.nvidia.text_embedder.DeepsetNvidiaTextEmbedder
    init_parameters:
      normalize_embeddings: true
      model: intfloat/e5-base-v2

  embedding_retriever:
    # Selects the most similar documents from the document store
    type: haystack_integrations.components.retrievers.opensearch.embedding_retriever.OpenSearchEmbeddingRetriever
    init_parameters:
      document_store:
        type: haystack_integrations.document_stores.opensearch.document_store.OpenSearchDocumentStore
        init_parameters:
          embedding_dim: 768
          hosts:
          index: ""
          max_chunk_bytes: 104857600
          return_embedding: false
          method:
          mappings:
          settings:
            index.knn: true
          create_index: true
          http_auth:
          use_ssl:
          verify_certs:
          timeout:
      top_k: 20 # The number of results to return

  ranker:
    type: deepset_cloud_custom_nodes.rankers.nvidia.ranker.DeepsetNvidiaRanker
    init_parameters:
      model: tomaarsen/Qwen3-Reranker-0.6B-seq-cls
      top_k: 20

connections:
- sender: query_embedder.embedding
  receiver: embedding_retriever.query_embedding
- sender: embedding_retriever.documents
  receiver: ranker.documents

inputs:
  query:
  - query_embedder.text
  - ranker.query
  filters:
  - embedding_retriever.filters

outputs:
  documents: ranker.documents

max_runs_per_component: 100

metadata: {}

RAG Pipeline

For a pipeline that returns both the generated answer and the source documents, add documents and answers to the Output component card and connect them to the components that should produce the documents and answers. Here is an example:

components:
  retriever:
    # Selects the most similar documents from the document store
    type: haystack_integrations.components.retrievers.opensearch.open_search_hybrid_retriever.OpenSearchHybridRetriever
    init_parameters:
      document_store:
        type: haystack_integrations.document_stores.opensearch.document_store.OpenSearchDocumentStore
        init_parameters:
          embedding_dim: 768
          hosts:
          index: ""
          max_chunk_bytes: 104857600
          return_embedding: false
          method:
          mappings:
          settings:
            index.knn: true
          create_index: true
          http_auth:
          use_ssl:
          verify_certs:
          timeout:
      top_k: 20 # The number of results to return
      fuzziness: 0
      embedder:
        type: deepset_cloud_custom_nodes.embedders.nvidia.text_embedder.DeepsetNvidiaTextEmbedder
        init_parameters:
          normalize_embeddings: true
          model: intfloat/e5-base-v2

  ranker:
    type: deepset_cloud_custom_nodes.rankers.nvidia.ranker.DeepsetNvidiaRanker
    init_parameters:
      model: tomaarsen/Qwen3-Reranker-0.6B-seq-cls
      top_k: 8

  meta_field_grouping_ranker:
    type: haystack.components.rankers.meta_field_grouping_ranker.MetaFieldGroupingRanker
    init_parameters:
      group_by: file_id
      subgroup_by:
      sort_docs_by: split_id

  llm:
    type: haystack.components.generators.chat.llm.LLM
    init_parameters:
      # You can swap this for any other model. Switch to the Builder view and choose another model from the list on the component card.
      chat_generator:
        type: haystack.components.generators.chat.openai.OpenAIChatGenerator
        init_parameters:
          model: "gpt-5.4"
          generation_kwargs:
            max_completion_tokens: 650
            temperature: 0.0
      user_prompt: |-
        {% message role="user" %}
        You are a technical expert.
        You answer questions truthfully based on provided documents.
        Ignore typing errors in the question.
        For each document check whether it is related to the question.
        Only use documents that are related to the question to answer it.
        Ignore documents that are not related to the question.
        If the answer exists in several documents, summarize them.
        Only answer based on the documents provided. Don't make things up.
        Just output the structured, informative and precise answer and nothing else.
        If the documents can't answer the question, say so.
        Always use references in the form [NUMBER OF DOCUMENT] when using information from a document, e.g. [3] for Document [3] .
        Never name the documents, only enter a number in square brackets as a reference.
        The reference must only refer to the number that comes in square brackets after the document.
        Otherwise, do not use brackets in your answer and reference ONLY the number of the document without mentioning the word document.

        These are the documents:
        {%- if documents|length > 0 %}
        {%- for document in documents %}
        Document [{{ loop.index }}] :
        Name of Source File: {{ document.meta.file_name }}
        {{ document.content }}
        {% endfor -%}
        {%- else %}
        No relevant documents found.
        Respond with "Sorry, no matching documents were found, please adjust the filters or try a different question."
        {% endif %}

        Question: {{ question }}
        Answer:
        {% endmessage %}
      required_variables: "*"

  answer_builder:
    type: deepset_cloud_custom_nodes.augmenters.deepset_answer_builder.DeepsetAnswerBuilder
    init_parameters:
      reference_pattern: acm

  attachments_joiner:
    type: haystack.components.joiners.document_joiner.DocumentJoiner
    init_parameters:
      join_mode: concatenate
      weights:
      top_k:
      sort_by_score: true

  multi_file_converter:
    type: haystack.core.super_component.super_component.SuperComponent
    init_parameters:
      input_mapping:
        sources:
        - file_classifier.sources
      is_pipeline_async: false
      output_mapping:
        score_adder.output: documents
      pipeline:
        components:
          file_classifier:
            type: haystack.components.routers.file_type_router.FileTypeRouter
            init_parameters:
              mime_types:
              - text/plain
              - application/pdf
              - text/markdown
              - text/html
              - application/vnd.openxmlformats-officedocument.wordprocessingml.document
              - application/vnd.openxmlformats-officedocument.presentationml.presentation
              - application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
              - text/csv

          text_converter:
            type: haystack.components.converters.txt.TextFileToDocument
            init_parameters:
              encoding: utf-8

          pdf_converter:
            type: haystack.components.converters.pdfminer.PDFMinerToDocument
            init_parameters:
              line_overlap: 0.5
              char_margin: 2
              line_margin: 0.5
              word_margin: 0.1
              boxes_flow: 0.5
              detect_vertical: true
              all_texts: false
              store_full_path: false

          markdown_converter:
            type: haystack.components.converters.txt.TextFileToDocument
            init_parameters:
              encoding: utf-8

          html_converter:
            type: haystack.components.converters.html.HTMLToDocument
            init_parameters:
              extraction_kwargs:
                output_format: markdown
                target_language:
                include_tables: true
                include_links: true

          docx_converter:
            type: haystack.components.converters.docx.DOCXToDocument
            init_parameters:
              link_format: markdown

          pptx_converter:
            type: haystack.components.converters.pptx.PPTXToDocument
            init_parameters: {}

          xlsx_converter:
            type: haystack.components.converters.xlsx.XLSXToDocument
            init_parameters: {}

          csv_converter:
            type: haystack.components.converters.csv.CSVToDocument
            init_parameters:
              encoding: utf-8

          splitter:
            type: haystack.components.preprocessors.document_splitter.DocumentSplitter
            init_parameters:
              split_by: word
              split_length: 250
              split_overlap: 30
              respect_sentence_boundary: true
              language: en

          score_adder:
            type: haystack.components.converters.output_adapter.OutputAdapter
            init_parameters:
              template: |
                {%- set scored_documents = [] -%}
                {%- for document in documents -%}
                  {%- set doc_dict = document.to_dict() -%}
                  {%- set _ = doc_dict.update({'score': 100.0}) -%}
                  {%- set scored_doc = document.from_dict(doc_dict) -%}
                  {%- set _ = scored_documents.append(scored_doc) -%}
                {%- endfor -%}
                {{ scored_documents }}
              output_type: List[haystack.Document]
              custom_filters:
              unsafe: true

          tabular_joiner:
            type: haystack.components.joiners.document_joiner.DocumentJoiner
            init_parameters:
              join_mode: concatenate
              sort_by_score: false
        connections:
        - sender: file_classifier.text/plain
          receiver: text_converter.sources
        - sender: file_classifier.application/pdf
          receiver: pdf_converter.sources
        - sender: file_classifier.text/markdown
          receiver: markdown_converter.sources
        - sender: file_classifier.text/html
          receiver: html_converter.sources
        - sender: file_classifier.application/vnd.openxmlformats-officedocument.wordprocessingml.document
          receiver: docx_converter.sources
        - sender: file_classifier.application/vnd.openxmlformats-officedocument.presentationml.presentation
          receiver: pptx_converter.sources
        - sender: file_classifier.application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
          receiver: xlsx_converter.sources
        - sender: file_classifier.text/csv
          receiver: csv_converter.sources
        - sender: text_converter.documents
          receiver: splitter.documents
        - sender: pdf_converter.documents
          receiver: splitter.documents
        - sender: markdown_converter.documents
          receiver: splitter.documents
        - sender: html_converter.documents
          receiver: splitter.documents
        - sender: pptx_converter.documents
          receiver: splitter.documents
        - sender: docx_converter.documents
          receiver: splitter.documents
        - sender: xlsx_converter.documents
          receiver: tabular_joiner.documents
        - sender: csv_converter.documents
          receiver: tabular_joiner.documents
        - sender: splitter.documents
          receiver: tabular_joiner.documents
        - sender: tabular_joiner.documents
          receiver: score_adder.documents

connections:
- sender: retriever.documents
  receiver: ranker.documents
- sender: ranker.documents
  receiver: meta_field_grouping_ranker.documents
- sender: llm.last_message
  receiver: answer_builder.replies
- sender: multi_file_converter.documents
  receiver: attachments_joiner.documents
- sender: meta_field_grouping_ranker.documents
  receiver: attachments_joiner.documents
- sender: attachments_joiner.documents
  receiver: answer_builder.documents
- sender: attachments_joiner.documents
  receiver: llm.documents

inputs:
  query:
  - retriever.query
  - ranker.query
  - llm.question
  - answer_builder.query
  filters:
  - retriever.filters_bm25
  - retriever.filters_embedding
  files:
  - multi_file_converter.sources

outputs:
  documents: attachments_joiner.documents
  answers: answer_builder.answers
  messages: llm.messages

max_runs_per_component: 100

metadata: {}

Extractive QA Pipeline

For a pipeline that returns structured answers, add answers to the Output component card and connect it to the component that should produce the answers. Here is an example:

components:
  retriever:
    # Selects the most similar documents from the document store
    type: haystack_integrations.components.retrievers.opensearch.open_search_hybrid_retriever.OpenSearchHybridRetriever
    init_parameters:
      document_store:
        type: haystack_integrations.document_stores.opensearch.document_store.OpenSearchDocumentStore
        init_parameters:
          embedding_dim: 768
          hosts:
          index: ""
          max_chunk_bytes: 104857600
          return_embedding: false
          method:
          mappings:
          settings:
            index.knn: true
          create_index: true
          http_auth:
          use_ssl:
          verify_certs:
          timeout:
      top_k: 20 # The number of results to return
      fuzziness: 0
      embedder:
        type: deepset_cloud_custom_nodes.embedders.nvidia.text_embedder.DeepsetNvidiaTextEmbedder
        init_parameters:
          normalize_embeddings: true
          model: intfloat/e5-base-v2

  ranker:
    type: deepset_cloud_custom_nodes.rankers.nvidia.ranker.DeepsetNvidiaRanker
    init_parameters:
      model: tomaarsen/Qwen3-Reranker-0.6B-seq-cls
      top_k: 10

  reader:
    type: haystack.components.readers.extractive.ExtractiveReader
    init_parameters:
      answers_per_seq: 20
      calibration_factor: 1.0
      max_seq_length: 384
      model: "deepset/deberta-v3-large-squad2"
      model_kwargs:
        torch_dtype: "torch.float16"
      no_answer: false
      top_k: 10

  attachments_joiner:
    type: haystack.components.joiners.document_joiner.DocumentJoiner
    init_parameters:
      join_mode: concatenate
      weights:
      top_k:
      sort_by_score: true

  multi_file_converter:
    type: haystack.core.super_component.super_component.SuperComponent
    init_parameters:
      input_mapping:
        sources:
        - file_classifier.sources
      is_pipeline_async: false
      output_mapping:
        score_adder.output: documents
      pipeline:
        components:
          file_classifier:
            type: haystack.components.routers.file_type_router.FileTypeRouter
            init_parameters:
              mime_types:
              - text/plain
              - application/pdf
              - text/markdown
              - text/html
              - application/vnd.openxmlformats-officedocument.wordprocessingml.document
              - application/vnd.openxmlformats-officedocument.presentationml.presentation
              - application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
              - text/csv

          text_converter:
            type: haystack.components.converters.txt.TextFileToDocument
            init_parameters:
              encoding: utf-8

          pdf_converter:
            type: haystack.components.converters.pdfminer.PDFMinerToDocument
            init_parameters:
              line_overlap: 0.5
              char_margin: 2
              line_margin: 0.5
              word_margin: 0.1
              boxes_flow: 0.5
              detect_vertical: true
              all_texts: false
              store_full_path: false

          markdown_converter:
            type: haystack.components.converters.txt.TextFileToDocument
            init_parameters:
              encoding: utf-8

          html_converter:
            type: haystack.components.converters.html.HTMLToDocument
            init_parameters:
              # A dictionary of keyword arguments to customize how you want to extract content from your HTML files.
              # For the full list of available arguments, see
              # the [Trafilatura documentation](https://trafilatura.readthedocs.io/en/latest/corefunctions.html#extract).
              extraction_kwargs:
                output_format: markdown # Extract text from HTML. You can also also choose "txt"
                target_language: # You can define a language (using the ISO 639-1 format) to discard documents that don't match that language.
                include_tables: true # If true, includes tables in the output
                include_links: true # If true, keeps links along with their targets

          docx_converter:
            type: haystack.components.converters.docx.DOCXToDocument
            init_parameters:
              link_format: markdown

          pptx_converter:
            type: haystack.components.converters.pptx.PPTXToDocument
            init_parameters: {}

          xlsx_converter:
            type: haystack.components.converters.xlsx.XLSXToDocument
            init_parameters: {}

          csv_converter:
            type: haystack.components.converters.csv.CSVToDocument
            init_parameters:
              encoding: utf-8

          splitter:
            type: haystack.components.preprocessors.document_splitter.DocumentSplitter
            init_parameters:
              split_by: word
              split_length: 250
              split_overlap: 30
              respect_sentence_boundary: true
              language: en

          score_adder:
            type: haystack.components.converters.output_adapter.OutputAdapter
            init_parameters:
              template: |
                {%- set scored_documents = [] -%}
                {%- for document in documents -%}
                  {%- set doc_dict = document.to_dict() -%}
                  {%- set _ = doc_dict.update({'score': 100.0}) -%}
                  {%- set scored_doc = document.from_dict(doc_dict) -%}
                  {%- set _ = scored_documents.append(scored_doc) -%}
                {%- endfor -%}
                {{ scored_documents }}
              output_type: List[haystack.Document]
              custom_filters:
              unsafe: true

          tabular_joiner:
            type: haystack.components.joiners.document_joiner.DocumentJoiner
            init_parameters:
              join_mode: concatenate
              sort_by_score: false
        connections:
        - sender: file_classifier.text/plain
          receiver: text_converter.sources
        - sender: file_classifier.application/pdf
          receiver: pdf_converter.sources
        - sender: file_classifier.text/markdown
          receiver: markdown_converter.sources
        - sender: file_classifier.text/html
          receiver: html_converter.sources
        - sender: file_classifier.application/vnd.openxmlformats-officedocument.wordprocessingml.document
          receiver: docx_converter.sources
        - sender: file_classifier.application/vnd.openxmlformats-officedocument.presentationml.presentation
          receiver: pptx_converter.sources
        - sender: file_classifier.application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
          receiver: xlsx_converter.sources
        - sender: file_classifier.text/csv
          receiver: csv_converter.sources
        - sender: text_converter.documents
          receiver: splitter.documents
        - sender: pdf_converter.documents
          receiver: splitter.documents
        - sender: markdown_converter.documents
          receiver: splitter.documents
        - sender: html_converter.documents
          receiver: splitter.documents
        - sender: pptx_converter.documents
          receiver: splitter.documents
        - sender: docx_converter.documents
          receiver: splitter.documents
        - sender: xlsx_converter.documents
          receiver: tabular_joiner.documents
        - sender: csv_converter.documents
          receiver: tabular_joiner.documents
        - sender: splitter.documents
          receiver: tabular_joiner.documents
        - sender: tabular_joiner.documents
          receiver: score_adder.documents

connections:
- sender: retriever.documents
  receiver: ranker.documents
- sender: ranker.documents
  receiver: attachments_joiner.documents
- sender: multi_file_converter.documents
  receiver: attachments_joiner.documents
- sender: attachments_joiner.documents
  receiver: reader.documents

inputs:
  query:
  - retriever.query
  - ranker.query
  - reader.query
  filters:
  - retriever.filters_bm25
  - retriever.filters_embedding
  files:
  - multi_file_converter.sources

outputs:
  documents: attachments_joiner.documents
  answers: reader.answers

max_runs_per_component: 100

metadata: {}