Fin API Platform

Explore our APIs

The Fin API platform includes APIs for answer generation and knowledge retrieval, available as a set or independently.

• [ 1 ]

  Fin Apex API

  

  Access the generative model at the core of Fin. Fin Apex is the best-performing customer service LLM, outperforming GPT-5.4 and Opus 4.5 on resolution rate, hallucination, and speed.

  Key Stats

  • 1.12.8% higher resolution rate than the latest frontier models
  • 1.265% reduction in hallucinations vs Sonnet 4.0
  • 1.30.6s faster time to first token than nearest competitor
• [ 2 ]

  Fin RAG API

  Access Fin's unified retrieval-augmented generation pipeline over API, including Fin Apex 1.0, Fin Retrieval, and Fin Reranker models.

  Key Stats

  • 2.167% average resolution rate
  • 2.284% average resolution rate at the 90th percentile
• [ 3 ]

  Fin Retrieval API

  A custom retrieval model optimised for customer service use cases, with a carefully optimised tradeoff between efficiency and quality, proven at the largest production scales.

  Key Stats

  • 3.1+20 pp. precision vs Voyage-Large-3
  • 3.2Custom vector retrieval optimised on apps with 10s of millions of items
• [ 4 ]

  Fin Reranker API

  Use the heavy reranker powering Fin to sort candidate items by relevance, optimised for your LLMs context window.

  Key Stats

  • 4.1+16.7% NDCG vs Cohere v 3.5, for Fin reranking
  • 4.2Battle-tested heuristic and custom LLM powered context sensitive reranking