If you’re building a SaaS app and need an AI API for summarization + information extraction, you generally have three good paths:

1) Use a general-purpose LLM API

Best when you want flexibility for:

• summarization
• structured extraction
• classification
• rewriting
• Q&A over text

Examples:

• OpenAI API
• Anthropic API
• Google Gemini API

Why this is a good fit:

• one API can handle multiple tasks
• easy to prompt for JSON output
• works well across many document types

2) Use a document-processing API

Best when your inputs are PDFs, scans, forms, invoices, or contracts.

Examples:

• Google Document AI
• AWS Textract
• Azure Document Intelligence

Why:

• better for OCR and layout-aware extraction
• can extract tables, fields, and structured data more reliably than a plain LLM alone

3) Use a hybrid approach

Often the best SaaS architecture:

• OCR / document parser for text extraction
• LLM for summarization and semantic extraction
• optional validation layer to check JSON/schema consistency

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What I’d recommend

If your primary needs are summarization and extraction from text, start with a general-purpose LLM API and require structured JSON output.

If your inputs are documents/files, combine:

• Document AI / OCR for text cleanup
• LLM for summarization and extraction

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Key features to look for

When choosing an API, check for:

• Structured outputs / JSON mode
• Large context window
• Low latency
• Good rate limits / scalability
• Cost per token
• Data privacy / retention policy
• Tool/function calling
• Batch processing support

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Example use cases

Summarization

• meeting notes
• customer support tickets
• legal docs
• research articles

Extraction

• names, dates, amounts
• entities and relationships
• key clauses from contracts
• fields from invoices or resumes

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Simple recommendation

If you want a straightforward starting point:

• use OpenAI API for summarization and extraction
• request JSON output
• add document OCR later if you need file handling

If you want, I can also give you:

1. a side-by-side comparison of OpenAI vs Anthropic vs Gemini, or
2. a sample API design for a SaaS summarization/extraction pipeline.