undermybelt Nutrient Document Processing
Note: This skill integrates with the Nutrient commercial API. Review their terms before use.
Process documents with the Nutrient DWS Processor API. Convert formats, extract text and tables, OCR scanned documents, redact PII, add watermarks, digitally sign, and fill PDF forms.
Setup
Get a free API key at nutrient.io
export NUTRIENT_API_KEY="pdf_live_..."
All requests go to https://api.nutrient.io/build as multipart POST with an instructions JSON field.
Operations
Convert Documents
# DOCX to PDF
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.docx=@document.docx" \
-F 'instructions={"parts":[{"file":"document.docx"}]}' \
-o output.pdf
# PDF to DOCX
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.pdf=@document.pdf" \
-F 'instructions={"parts":[{"file":"document.pdf"}],"output":{"type":"docx"}}' \
-o output.docx
# HTML to PDF
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "index.html=@index.html" \
-F 'instructions={"parts":[{"html":"index.html"}]}' \
-o output.pdf
Supported inputs: PDF, DOCX, XLSX, PPTX, DOC, XLS, PPT, PPS, PPSX, ODT, RTF, HTML, JPG, PNG, TIFF, HEIC, GIF, WebP, SVG, TGA, EPS.
Extract Text and Data
# Extract plain text
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.pdf=@document.pdf" \
-F 'instructions={"parts":[{"file":"document.pdf"}],"output":{"type":"text"}}' \
-o output.txt
# Extract tables as Excel
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.pdf=@document.pdf" \
-F 'instructions={"parts":[{"file":"document.pdf"}],"output":{"type":"xlsx"}}' \
-o tables.xlsx
OCR Scanned Documents
# OCR to searchable PDF (supports 100+ languages)
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "scanned.pdf=@scanned.pdf" \
-F 'instructions={"parts":[{"file":"scanned.pdf"}],"actions":[{"type":"ocr","language":"english"}]}' \
-o searchable.pdf
Languages: Supports 100+ languages via ISO 639-2 codes (e.g., eng, deu, fra, spa, jpn, kor, chi_sim, chi_tra, ara, hin, rus). Full language names like english or german also work. See the complete OCR language table for all supported codes.
Redact Sensitive Information
# Pattern-based (SSN, email)
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.pdf=@document.pdf" \
-F 'instructions={"parts":[{"file":"document.pdf"}],"actions":[{"type":"redaction","strategy":"preset","strategyOptions":{"preset":"social-security-number"}},{"type":"redaction","strategy":"preset","strategyOptions":{"preset":"email-address"}}]}' \
-o redacted.pdf
# Regex-based
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.pdf=@document.pdf" \
-F 'instructions={"parts":[{"file":"document.pdf"}],"actions":[{"type":"redaction","strategy":"regex","strategyOptions":{"regex":"\\b[A-Z]{2}\\d{6}\\b"}}]}' \
-o redacted.pdf
Presets: social-security-number, email-address, credit-card-number, international-phone-number, north-american-phone-number, date, time, url, ipv4, ipv6, mac-address, us-zip-code, vin.
Add Watermarks
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.pdf=@document.pdf" \
-F 'instructions={"parts":[{"file":"document.pdf"}],"actions":[{"type":"watermark","text":"CONFIDENTIAL","fontSize":72,"opacity":0.3,"rotation":-45}]}' \
-o watermarked.pdf
Digital Signatures
# Self-signed CMS signature
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "document.pdf=@document.pdf" \
-F 'instructions={"parts":[{"file":"document.pdf"}],"actions":[{"type":"sign","signatureType":"cms"}]}' \
-o signed.pdf
Fill PDF Forms
curl -X POST https://api.nutrient.io/build \
-H "Authorization: Bearer $NUTRIENT_API_KEY" \
-F "form.pdf=@form.pdf" \
-F 'instructions={"parts":[{"file":"form.pdf"}],"actions":[{"type":"fillForm","formFields":{"name":"Jane Smith","email":"jane@example.com","date":"2026-02-06"}}]}' \
-o filled.pdf
MCP Server (Alternative)
For native tool integration, use the MCP server instead of curl:
{
"mcpServers": {
"nutrient-dws": {
"command": "npx",
"args": ["-y", "@nutrient-sdk/dws-mcp-server"],
"env": {
"NUTRIENT_DWS_API_KEY": "YOUR_API_KEY",
"SANDBOX_PATH": "/path/to/working/directory"
}
}
}
}
When to Use
- Converting documents between formats (PDF, DOCX, XLSX, PPTX, HTML, images)
- Extracting text, tables, or key-value pairs from PDFs
- OCR on scanned documents or images
- Redacting PII before sharing documents
- Adding watermarks to drafts or confidential documents
- Digitally signing contracts or agreements
- Filling PDF forms programmatically