Forward Future Tools Library
Citations API
Citations API lets developers build Claude applications that link generated claims to exact passages in supplied documents, for research, document analysis, and support systems.
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›What is Citations API?
Citations is an API feature that lets Claude ground answers in documents provided with a query. It returns references to the exact sentences or passages used to generate claims, helping applications show where their answers came from. The feature is available through the Anthropic API, Google Cloud Vertex AI, and Amazon Bedrock.
›What are the pros and cons of Citations API?
Strengths
Points users to the exact passages Claude used in its response
Provides structured citation data with location information for several document formats
Reduces reliance on custom prompts for generating source references
Available through the Anthropic API and Google Cloud Vertex AI, with Amazon Bedrock availability announced later
Trade-offs
Cites only documents supplied by the developer and does not independently verify claims against external sources
Requires developers to add source documents to the model context alongside the query
Designed as a Claude Messages API feature, so it requires API integration rather than functioning as a standalone citation service
›What are Citations API’s key features?
Generates citations for claims inferred from supplied source documents
Returns structured references to cited passages
Supports character indices for plain text, page numbers for PDFs, and block indices for custom content
Works with document summarization and questions across document collections
Supports citation-based customer support responses using manuals, FAQs, and tickets
›What are the best use cases for Citations API?
Summarize case files or other long documents with each key point linked to its source
Answer questions across financial statements or other document collections
Build customer support systems that cite product manuals, FAQs, and support tickets
Add source attribution to AI-generated research or analysis applications
›What is the pricing for Citations API?
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›Who is Citations API best for?
developersUseful for building applications that need structured source references in generated answers.
researchersWorks well for document-based analysis where each finding needs to trace back to supplied material.
content creatorsCan add passage-level attribution to content generated from a controlled collection of source documents.
Not for
- Teams that need independent fact-checking against live web sources should use a verification or search service instead.
- Users seeking a standalone research or citation interface should look beyond this API feature, which requires application development.
›What’s new with Citations API?
- Anthropic launched Citations on its API, with availability on Vertex AI and a later Bedrock updateJune 2025 · source
›What are the best Citations API alternatives?
PerplexityChoose this instead if the application needs AI search across external information rather than citations limited to supplied documents.→
ElicitChoose this instead if the main task is literature review and evidence synthesis rather than adding citations to a custom Claude application.→
Genny by Lovo.ai→
Pieces→