DocStrange by Nanonets

Document extraction API — convert PDFs, images, and documents to markdown, JSON, or CSV with per-field confidence scoring.

Get your API key: https://docstrange.nanonets.com/app

Quick Start

curl -X POST "https://extraction-api.nanonets.com/api/v1/extract/sync" \
  -H "Authorization: Bearer $DOCSTRANGE_API_KEY" \
  -F "file=@document.pdf" \
  -F "output_format=markdown"

Response:

{
  "success": true,
  "record_id": "550e8400-e29b-41d4-a716-446655440000",
  "status": "completed",
  "result": {
    "markdown": {
      "content": "# Invoice\n\n**Invoice Number:** INV-2024-001..."
    }
  }
}

Setup

1. Get Your API Key

# Visit the dashboard
https://docstrange.nanonets.com/app

Save your API key:

export DOCSTRANGE_API_KEY="your_api_key_here"

2. OpenClaw Configuration (Optional)

Recommended: Use environment variables (most secure):

{
  skills: {
    entries: {
      "docstrange": {
        enabled: true,
        // API key loaded from environment variable DOCSTRANGE_API_KEY
      },
    },
  },
}

Alternative: Store in config file (use with caution):

{
  skills: {
    entries: {
      "docstrange": {
        enabled: true,
        env: {
          DOCSTRANGE_API_KEY: "your_api_key_here",
        },
      },
    },
  },
}

Security Note: If storing API keys in ~/.openclaw/openclaw.json:

Set file permissions: chmod 600 ~/.openclaw/openclaw.json
Never commit this file to version control
Prefer environment variables or your agent's secret store when possible
Rotate keys regularly and limit API key permissions if supported

Common Tasks

Extract to Markdown

curl -X POST "https://extraction-api.nanonets.com/api/v1/extract/sync" \
  -H "Authorization: Bearer $DOCSTRANGE_API_KEY" \
  -F "file=@document.pdf" \
  -F "output_format=markdown"

Access content: response["result"]["markdown"]["content"]

Extract JSON Fields

Simple field list:

curl -X POST "https://extraction-api.nanonets.com/api/v1/extract/sync" \
  -H "Authorization: Bearer $DOCSTRANGE_API_KEY" \
  -F "file=@invoice.pdf" \
  -F "output_format=json" \
  -F 'json_options=["invoice_number", "date", "total_amount", "vendor"]' \
  -F "include_metadata=confidence_score"

With JSON schema:

curl -X POST "https://extraction-api.nanonets.com/api/v1/extract/sync" \
  -H "Authorization: Bearer $DOCSTRANGE_API_KEY" \
  -F "file=@invoice.pdf" \
  -F "output_format=json" \
  -F 'json_options={"type": "object", "properties": {"invoice_number": {"type": "string"}, "total_amount": {"type": "number"}}}'

Response with confidence scores:

{
  "result": {
    "json": {
      "content": {
        "invoice_number": "INV-2024-001",
        "total_amount": 500.00
      },
      "metadata": {
        "confidence_score": {
          "invoice_number": 98,
          "total_amount": 99
        }
      }
    }
  }
}

Extract Tables to CSV

curl -X POST "https://extraction-api.nanonets.com/api/v1/extract/sync" \
  -H "Authorization: Bearer $DOCSTRANGE_API_KEY" \
  -F "file=@table.pdf" \
  -F "output_format=csv" \
  -F "csv_options=table"

Async Extraction (Large Documents)

For documents >5 pages, use async and poll:

Queue the document:

curl -X POST "https://extraction-api.nanonets.com/api/v1/extract/async" \
  -H "Authorization: Bearer $DOCSTRANGE_API_KEY" \
  -F "file=@large-document.pdf" \
  -F "output_format=markdown"

# Returns: {"record_id": "12345", "status": "processing"}

Poll for results:

curl -X GET "https://extraction-api.nanonets.com/api/v1/extract/results/12345" \
  -H "Authorization: Bearer $DOCSTRANGE_API_KEY"

# Returns: {"status": "completed", "result": {...}}

Advanced Features

Bounding Boxes

Get element coordinates for layout analysis:

-F "include_metadata=bounding_boxes"

Hierarchy Output

Extract document structure (sections, tables, key-value pairs):

-F "json_options=hierarchy_output"

Financial Documents Mode

Enhanced table and number formatting:

-F "markdown_options=financial-docs"

Custom Instructions

Guide extraction with prompts:

-F "custom_instructions=Focus on financial data. Ignore headers."
-F "prompt_mode=append"

Multiple Formats

Request multiple formats in one call:

-F "output_format=markdown,json"

When to Use

Use DocStrange For:

Invoice and receipt processing
Contract text extraction
Bank statement parsing
Form digitization
Image OCR (scanned documents)

Don't Use For:

Documents >5 pages with sync (use async)
Video/audio transcription
Non-document images

Best Practices

Document Size	Endpoint	Notes
<=5 pages	`/extract/sync`	Immediate response
>5 pages	`/extract/async`	Poll for results

JSON Extraction:

Field list: ["field1", "field2"] — quick extractions
JSON schema: {"type": "object", ...} — strict typing, nested data

Confidence Scores:

Add include_metadata=confidence_score
Scores are 0-100 per field
Review fields <80 manually

Schema Templates

Invoice

{
  "type": "object",
  "properties": {
    "invoice_number": {"type": "string"},
    "date": {"type": "string"},
    "vendor": {"type": "string"},
    "total": {"type": "number"},
    "line_items": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "description": {"type": "string"},
          "quantity": {"type": "number"},
          "price": {"type": "number"}
        }
      }
    }
  }
}

Receipt

{
  "type": "object",
  "properties": {
    "merchant": {"type": "string"},
    "date": {"type": "string"},
    "total": {"type": "number"},
    "items": {
      "type": "array",
      "items": {"type": "object", "properties": {"name": {"type": "string"}, "price": {"type": "number"}}}
    }
  }
}

Security & Privacy

Data Handling

Important: Documents uploaded to DocStrange are transmitted to https://extraction-api.nanonets.com and processed on external servers.

Before uploading sensitive documents:

Review Nanonets' privacy policy and data retention policies: https://docstrange.nanonets.com/docs
Verify encryption in transit (HTTPS) and at rest
Confirm data deletion/retention timelines
Test with non-sensitive sample documents first

Best practices:

Do not upload highly sensitive PII (SSNs, medical records, financial account numbers) until you've confirmed the service's security and compliance posture
Use API keys with limited permissions/scopes if available
Rotate API keys regularly (every 90 days recommended)
Monitor API usage logs for unauthorized access
Never log or commit API keys to repositories or examples

File Size Limits

Sync endpoint: Recommended for documents ≤5 pages
Async endpoint: Use for documents >5 pages to avoid timeouts
Large files: Consider using file_url with publicly accessible URLs instead of uploading large files directly

Operational Safeguards

Always use environment variables or secure secret stores for API keys
Never include real API keys in code examples or documentation
Use placeholder values like "your_api_key_here" in examples
Set appropriate file permissions on configuration files (600 for JSON configs)
Enable API key rotation and monitor usage through the dashboard

Troubleshooting

400 Bad Request:

Provide exactly one input: file, file_url, or file_base64
Verify API key is valid

Sync Timeout:

Use async for documents >5 pages
Poll /extract/results/{record_id}

Missing Confidence Scores:

Requires json_options (field list or schema)
Add include_metadata=confidence_score

Authentication Errors:

Verify DOCSTRANGE_API_KEY environment variable is set
Check API key hasn't expired or been revoked
Ensure no extra whitespace in API key value

Pre-Publish Security Checklist

Before publishing or updating this skill, verify:

package.json declares requiredEnv and primaryEnv for DOCSTRANGE_API_KEY
package.json lists API endpoints in endpoints array
All code examples use placeholder values ("your_api_key_here") not real keys
No API keys or secrets are embedded in SKILL.md or package.json
Security & Privacy section documents data handling and risks
Configuration examples include security warnings for plaintext storage
File permission guidance is included for config files

References

API Docs: https://docstrange.nanonets.com/docs
Get API Key: https://docstrange.nanonets.com/app
Privacy Policy: https://docstrange.nanonets.com/docs (check for privacy/data policy links)

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