DWS Processor API: Convert, OCR, redact, and sign PDFs

Nutrient’s DWS Processor API is a cloud PDF API for PDF and Office files. Convert between formats, run OCR to make scans searchable, redact permanently, sign, fill forms, and generate PDFs from HTML. Chain the steps in one /build call, with nothing to install or host. Call it from an application, or give agents the same operations through Nutrient MCP.


Used by 3,000+ organizations worldwide, including 15 percent of Global 500 companies, with 1B+ document interactions a year.

Used by Lufthansa, Disney, Autodesk, UBS, Dropbox, IBM
Lufthansa
Disney
Autodesk
UBS
Dropbox
IBM

One API, one request

What do you want to do with your documents?

Convert documents

Convert Word, Excel, PowerPoint, HTML, images, and Markdown to PDF, and PDFs back to Office files, images, HTML, and Markdown.

Explore conversion
curl -X POST https://api.nutrient.io/processor/convert_to_pdf \
-H "Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document" \
-H "Authorization: Bearer your_api_key_here" \
-o result.pdf \
--fail \
--data-binary @document.docx

OCR scanned files

Make scans and images searchable, in more than 80 languages.

Explore OCR
curl -X POST https://api.nutrient.io/processor/ocr \
-H "Authorization: Bearer your_api_key_here" \
-o result.pdf \
--fail \
-F file=@document.pdf \
-F data='{
"language": "english"
}'

Redact sensitive data

Target content by search term, regex, or preset, or let AI redaction find it by meaning. Redaction permanently deletes the underlying text and images from the file, not just the visible layer.

Explore redaction
curl -X POST https://api.nutrient.io/processor/redact \
-H "Authorization: Bearer your_api_key_here" \
-o result.pdf \
--fail \
-F file=@document.pdf \
-F data='{
"strategy": "text",
"strategyOptions": {
"text": "macaque",
"caseSensitive": false
},
"redactionState": "apply"
}'

Sign documents

Apply visible or invisible certificate-based signatures, with long-term validation, that show whether a document changed after signing.

Explore digital signatures
curl -X POST https://api.nutrient.io/sign \
-H "Authorization: Bearer your_api_key_here" \
-o result.pdf \
--fail \
-F file=@document.pdf

Generate PDFs

Turn HTML into pixel-accurate PDFs for invoices, reports, and statements.

Explore PDF generation
curl -X POST https://api.nutrient.io/processor/generate_pdf \
-H "Authorization: Bearer your_api_key_here" \
-o result.pdf \
--fail \
-F html=@index.html

Chain steps in one call

One /build request runs several steps in order, and each step’s output feeds the next. This example runs OCR on a scan, redacts every email address, and saves the result as PDF/A. A pipeline such as “convert to PDF, OCR, redact, flatten, archive as PDF/A” is one request, not five. Inputs can be uploaded or passed as URLs.

Read the /build guide
{
"parts": [
{
"file": "document"
}
],
"actions": [
{
"type": "ocr",
"language": "english"
},
{
"type": "createRedactions",
"strategy": "preset",
"strategyOptions": {
"preset": "email-address"
}
},
{
"type": "applyRedactions"
}
],
"output": {
"type": "pdfa",
"conformance": "pdfa-2a"
}
}

Choose how you integrate

Samples cover C#, Java, JavaScript, PHP, and Python, and any language that can send an HTTP request can call /build.

Nutrient MCP
MCP MCP connections for agents

Nutrient MCP

Hosted MCP server for connecting AI agents to data extraction and document processing. Nothing to install.

TypeScript/JavaScript
SDK Official API client libraries

TypeScript/JavaScript client

Official client. Install with npm install @nutrient-sdk/dws-client-typescript.

Python
SDK Official API client libraries

Python client

Official client. Install with pip install nutrient-dws.

Zapier
NO-CODE Integrate using popular automation platforms

Zapier integration

Connect the Processor API to thousands of apps without code.

Postman
REST API Direct API access and testing tools

Postman collection

Try every endpoint before writing code.

Kiran Kaza
Head of Mobile Engineering
“Our team can focus on implementing the features specific to the DocuSign business domain while leaving the handling of PDFs to the experts.”
DocuSign

Security is our top priority

SOC 2 Type 2 audited

Nutrient’s infrastructure is SOC 2 Type 2 audited and GDPR compliant. See our privacy policy and security documentation for details on data handling.

HTTPS encryption

All communication between your application and Nutrient is done via HTTPS to ensure your data is encrypted when it’s sent to us.

Safe payment processing

All payments are handled by Paddle. Nutrient DWS Processor API never has direct access to any of your payment data.


PDF operations in one API

Each tool works on its own or as a step in a /build call. Pick a tool to see its parameters and code samples.


Converter API

EXPLORE MORE

Optimization and archiving

Compress and linearize PDFs, convert to PDF/A (versions 1 to 4) for long-term storage, and validate PDF/A files.


Start free

50 free Processor API credits every month

Watermarked output. No credit card required.

Your free plan includes:

    • 50 Processor API credits each month
    • Watermarked output
    • No credit card required

Frequently asked questions

What is the Nutrient DWS Processor API?

Nutrient’s DWS Processor API is a cloud PDF API that converts, OCRs, redacts, signs, fills, generates, and archives PDF and Office documents. A request sends files to the /build endpoint with a list of steps, and the API returns the finished document.

What operations does the Processor API support?

Nutrient’s DWS Processor API covers:

  • Conversion — Office, HTML, Markdown, and images to PDF, and PDF to Office, images, HTML, Markdown, PDF/A, and PDF/UA
  • OCR to searchable PDFs, in more than 80 languages
  • Redaction by search term, regex, or preset, plus AI redaction
  • Digital signatures, watermarks, and annotations
  • Creating and filling PDF forms
  • PDF security — passwords and permissions
  • PDF generation from HTML, and DOCX templating
  • Page operations — merge, split, rotate, reorder, duplicate, and delete
Does the Processor API use AI?

Nutrient’s DWS Processor API uses AI for one job: AI redaction, which finds sensitive data by meaning, not only by pattern. For AI that reads documents (extraction, classification, and splitting), see Nutrient’s AI document processing API.

What’s the difference between the Processor API and the Data Extraction API?

Nutrient’s Processor API changes files: It converts, OCRs, redacts, signs, and generates documents. Nutrient’s Data Extraction API reads them and returns text, tables, key-value pairs, and schema fields as JSON or Markdown, with confidence scores and citations. Many pipelines use both: Extract data with one and produce the final PDF with the other.

How does pricing work for the DWS Processor API?

Nutrient’s DWS Processor API includes 50 free credits a month. Paid plans start at $75 a month for 1,000 credits, and annual billing costs less. Each tool uses credits based on the operation and page count; see Processor API pricing for per-tool costs. To check what a request will cost before running it, send it to the free /analyze_build endpoint.

Is there a free tier available?

Yes. We offer a free tier with 50 credits per month so you can evaluate the API before upgrading.

On the free plan, output includes the “For Evaluation Purposes Only” watermark, even when you use a pdf_live_ key. Enable pay-as-you-go or choose a paid plan for watermark-free output.

Note that commercial use on the free tier is restricted for enterprises with more than 20 employees or more than $1 million in annual revenue.

How quickly can I integrate DWS Processor API into my application?

Most developers integrate our API in just a few hours. We provide official SDK libraries for TypeScript and Python, along with comprehensive documentation and code samples. Our getting started guide walks you through integration step-by-step, and you can test everything with our interactive API reference.

What file formats can I convert with the Processor API?

The Processor API supports extensive format conversion:

  • Input formats include PDF, Word (.doc, .docx), Excel (.xls, .xlsx), PowerPoint (.ppt, .pptx), HTML, and images (.png, .jpg, .jpeg, .tiff).
  • Output formats include PDF, DOCX, XLSX, PPTX, and images (JPG, PNG, WebP, TIFF).

The API handles bidirectional conversion — for example, PDF to Word for editing, then Word back to PDF for distribution. All conversions preserve formatting, fonts, images, and document structure with high fidelity.

How does the OCR feature work and what languages does it support?

Nutrient’s DWS Processor API runs OCR on scanned documents, images, and non-searchable PDFs, and it returns a searchable PDF with the original layout. It supports more than 80 languages.

Can I extract structured data from invoices, receipts, and forms?

Nutrient’s Data Extraction API does this, not the Processor API. The Processor API can convert PDF tables to an Excel workbook.

Can I process documents in batch or does it handle one at a time?

The Processor API is designed for both single-document and high-volume batch processing. You can process documents one at a time for real-time workflows (perfect for user-initiated operations like “Download as PDF”), or implement batch processing by making multiple API calls concurrently from your application. Our cloud infrastructure automatically scales to handle your workload, whether you’re processing a handful of documents a day or large batches. Many customers integrate the API into their ETL pipelines, document management systems, scheduled automation tasks (cron jobs), and webhook-triggered workflows for efficient batch operations. For long-running work, send a /build request as an async job and collect the result when it’s ready.

How secure is document processing with the Processor API?

Nutrient’s infrastructure is SOC 2 Type 2 audited and GDPR compliant. All communication between an application and Nutrient uses HTTPS, so data is encrypted when it’s sent, and redaction removes content permanently rather than covering it. Learn more about Nutrient’s security practices.

What happens if a document processing request fails?

The Processor API provides detailed error responses to help you handle failures gracefully. Common error scenarios include: invalid input format, corrupted or password-protected files, processing timeouts for extremely large documents, and insufficient credits. Our API returns clear error messages with specific codes indicating what went wrong and suggested resolutions. We recommend implementing retry logic with exponential backoff for transient errors, validating input files before processing, and monitoring your credit balance to avoid service interruptions. Our support team is available to help troubleshoot persistent issues.

How does HTML to PDF conversion handle complex layouts and custom fonts?

Our HTML to PDF engine is built on modern browser technology (Chromium), ensuring high-fidelity conversion that accurately renders complex web layouts. The engine supports:

  • Latest Web Standards: Full HTML5, CSS3, JavaScript, Flexbox, Grid, and responsive design.
  • Custom Fonts: Web fonts, Google Fonts, and custom font files with proper embedding.
  • Advanced Styling: Gradients, shadows, animations, and modern CSS features.
  • Images and Media: Background images, SVGs, and external resources.
  • Print Optimization: Page breaks, margins, headers/footers, and page sizing.

The rendered PDF looks exactly like the webpage in a modern browser. You can pass URLs or raw HTML, control page size and orientation, and configure margins and scaling for perfect output every time.

Can I chain multiple operations together in a single API call?

Yes! One of the most powerful features of the Processor API is the ability to chain multiple operations in a single workflow. For example, you can convert a Word document to PDF, apply a watermark, run OCR, and compress the file — all in one API call. This approach reduces API calls and network overhead, lowers costs (though you still pay credits for each operation), simplifies error handling, and ensures faster processing. Our API documentation includes examples of common chained workflows such as “Scan → OCR → Redact → Watermark” for sensitive documents, “Office → PDF → Optimize” for web distribution, and “PDF → Excel” for data analysis.

Does the Processor API support digital signatures for legal compliance?

Yes, the Processor API supports digital signatures with certificate-based authentication to ensure document integrity. Digital signatures provide cryptographic proof that the document hasn’t been altered since signing and verify the identity of the signer using X.509 certificates. Whether a signature meets a legal standard such as eIDAS depends on the certificate and the signing process you use, not on the API alone. Use cases include contract execution, regulatory document approval, secure form submissions, and automated document certification. The API also supports applying visible signature fields and timestamp authorities for additional verification.

What are the rate limits and how do they work?

Nutrient’s DWS Processor API allows 100 requests per minute per API key, on every plan. A request over the limit is rejected, so retry with exponential backoff. For higher volumes, contact Sales.

How does the AI-powered redaction feature work?

Our AI-powered redaction automatically identifies and permanently removes sensitive information from documents. The AI scans documents for personally identifiable information (PII) like names, addresses, phone numbers, and email addresses; financial data including credit card numbers, bank accounts, and SSNs; protected health information (PHI); and custom patterns you define. Unlike simple “cover-up” tools, our redaction permanently removes the underlying text and images from the PDF file, making recovery impossible. This helps with GDPR, HIPAA, and other privacy requirements. The API also supports rule-based redaction by search term, regex, or preset.

What’s the difference between the DWS Processor API and traditional on-premises PDF libraries?

The DWS Processor API offers several advantages over traditional on-premises PDF libraries:

  • Zero infrastructure — No servers to set up, scale, or maintain vs. deploying and managing your own servers.
  • Instant scalability — Automatically handles traffic spikes vs. capacity planning and hardware provisioning.
  • Always updated — Latest features and security patches vs. manual updates and version management.
  • Pay-as-you-go — Credit-based pricing vs. upfront licensing costs.
  • Multilanguage support — REST API works with any language vs. library-specific language bindings.

Self-hosted deployments may be preferred for strict data residency requirements or extremely high volumes where per-document costs favor self-hosting. We can help you evaluate which approach best fits your needs.

Ready to try it?

Get an API key and 50 free credits a month. Then run a first /build call in minutes.