--- site_search: "GET /ask?q={query} (read-only search over extend.ai and docs.extend.ai; returns links and quoted passages, not generated answers)" title: "Split API: Split Multi-Document PDFs by Type | Extend" description: "Split compound PDFs into typed sub-documents with page ranges, identifiers, and standalone file IDs. Extend's harness reaches 72.48% boundary F1 on PoliTax Split." canonical: https://www.extend.ai/split --- # Split API: Split Multi-Document PDFs by Type | Extend > Search this site and the docs: [`/ask?q=…`](/ask?q=webhook+retries) returns matching pages from extend.ai and docs.extend.ai, with quoted passages. Split API ## Break document bundles into typed sub-documents Boundary detection finds where each document starts and ends in a compound file, labels it with your types, and returns each one as a standalone file. [Try for free](https://dashboard.extend.ai/) · [Book a demo](https://www.extend.ai/get-started) ## What it does ### Typed page ranges Each split returns its type, start and end page, and a file ID you can pass straight to Extract or Classify. ### Identifiers per document An identifier key pulls a value such as an invoice number from each split; strict mode merges adjacent splits that share it. ### Performance or Light Choose the engine per splitter to trade accuracy against cost on long packets. ## Under the hood Segment multi-document files into individual subdocuments. ### Large document splitting High-precision splitting that maintains accuracy on 2,000+ page files. ### Instance detection Detect unique identifiers to separate multiple instances of the same document type, like splitting 50 invoices by invoice number. ### Intelligent boundary handling Smart overlap handles mid-page boundaries while keeping context intact. ### Cost-optimized splitting Toggle cost-optimized splitting for bulk jobs, or high precision for tough files. ## Benchmarks ### PoliTax Split: 72.48% Best boundary-detection F1 with Extend's harness The 30 largest compound tax filings in the public PoliTax corpus. Source: [PoliTax Split report](https://www.extend.ai/resources/document-splitting-benchmark.md) ### PoliTax Split: +8.3 to +28.4 F1 points over direct use of the same model The harness catches about two thirds or more of boundaries for every underlying model. Source: [PoliTax Split report](https://www.extend.ai/resources/document-splitting-benchmark.md) ## How to get started ### 1. Create an account Sign up at dashboard.extend.ai. New accounts get 10,000 free credits. Copy an API key from the Developers page and export it as EXTEND_API_KEY. [Sign up](https://dashboard.extend.ai/) · [Developers page](https://dashboard.extend.ai/developers) ### 2. Choose how to call Split Studio: try Split in the browser with no code. MCP: connect Claude, Cursor, or any MCP client to https://mcp.extend.ai/mcp. CLI: install with curl -fsSL https://extend.ai/install.sh | sh, then run extend setup. SDKs: pip install extend-ai or npm install extend-ai; Java and Go SDKs are also available. [Open Studio](https://dashboard.extend.ai/studio) · [MCP setup](https://www.extend.ai/agents/mcp.md) · [CLI setup](https://www.extend.ai/agents/cli.md) · [SDK docs](https://docs.extend.ai/sdks) ### 3. Process your first document Define the document types to look for. At least one type must be other. ```bash curl -X POST https://api.extend.ai/split \ -H "Authorization: Bearer $EXTEND_API_KEY" \ -H "x-extend-api-version: 2026-02-09" \ -H "Content-Type: application/json" \ -d '{ "file": { "url": "https://extend-public-files.s3.us-east-2.amazonaws.com/loan_application.pdf" }, "config": { "splitClassifications": [ { "id": "invoice", "type": "invoice", "description": "An invoice or bill for goods or services." }, { "id": "other", "type": "other", "description": "Any other document type." } ] } }' ``` ### 4. Move to production Send production traffic to POST /split_runs; the synchronous POST /split times out after 5 minutes. [Split File API reference](https://docs.extend.ai/api-reference/endpoints/split/split-file) ## Pricing From 0.5 credits per page with Light Split, with parsing billed on top. [See full pricing](https://www.extend.ai/pricing.md) ## Documentation - [Splitting overview](https://docs.extend.ai/splitting/overview) - [Split File API reference](https://docs.extend.ai/api-reference/endpoints/split/split-file) ## Related reading - [Extend's benchmark for document splitting](https://www.extend.ai/resources/document-splitting-benchmark.md) - [Product spotlight: the Splitter processor](https://www.extend.ai/resources/product-spotlight-splitter-processor.md) ## Use cases ### Lab & genomic reports Find the sections of 50-page reports that hold the fields you need before extracting. [Flatiron Health case study](https://www.extend.ai/resources/flatiron-case-study.md) ### Loan & mortgage packets Separate statements, pay stubs, and disclosures in one closing packet. [Real estate](https://www.extend.ai/real-estate.md) ### Claims bundles Break insurance, legal, and healthcare claim packets into typed documents. [Healthcare](https://www.extend.ai/healthcare.md) ### Compound tax filings Find form boundaries across hundreds of pages of schedules and supplements. [PoliTax Split benchmark](https://www.extend.ai/resources/document-splitting-benchmark.md) ### Batch scans Turn one scanned stack into a file per document, ready to route. [Splitter product spotlight](https://www.extend.ai/resources/product-spotlight-splitter-processor.md) ### Freight paperwork Separate bills of lading, invoices, and customs forms sent as one PDF. [Logistics](https://www.extend.ai/logistics.md) ## More products - [Parse](https://www.extend.ai/parse.md) - [Extract](https://www.extend.ai/extract.md) - [Verify](https://www.extend.ai/verify.md) - [Classify](https://www.extend.ai/classify.md) - [Edit](https://www.extend.ai/edit.md)