API Documentation

Complete reference for the Alterna PDF REST API. All endpoints, parameters, and code examples.

Base URL: https://app.alternapdf.comAuth: X-API-Key headerVersion: 2.5.1

Quick Start

terminal
curl -X POST "https://app.alternapdf.com/api/v1/convert/text-to-pdf" \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "Hello from the Alterna PDF API!"}' \
  --output hello.pdf

All endpoints require an X-API-Key header. Get your key at dashboard.alternapdf.com.

Document Conversion

POST
HTML to PDF/api/v1/convert/html-to-pdf

Convert HTML content or a live URL into a PDF with full CSS support.

POST
Text to PDF/api/v1/convert/text-to-pdf

Convert plain text into a formatted PDF with typography controls.

POST
Markdown to PDF/api/v1/convert/markdown-to-pdf

Convert Markdown into polished PDFs with themes and syntax highlighting.

POST
JSON to PDF/api/v1/convert/json-to-pdf

Transform JSON data into structured PDF reports with table formatting.

POST
Template to PDF/api/v1/pdf/from-template

Generate PDFs from stored templates with dynamic variable substitution.

Data Extraction

POST
PDF to Text/api/v1/convert/pdf-to-text

Extract text with multiple modes. Auto-OCR for scanned documents.

POST
PDF to HTML/api/v1/convert/pdf-to-html

Convert PDFs into clean, structured HTML preserving layout.

POST
PDF to Markdown/api/v1/convert/pdf-to-markdown

Convert PDFs into Markdown with heading, table, and code detection.

POST
PDF to Image/api/v1/convert/pdf-to-image

Render PDF pages as PNG, JPEG, or WebP images.

POST
Extract Images/api/v1/extract/pdf-images

Extract all embedded images from a PDF as a ZIP archive.

PDF Manipulation

POST
Merge PDFs/api/v1/pdf/merge

Combine multiple PDFs into a single document.

POST
Split PDF/api/v1/pdf/split

Split by pages, ranges, or fixed-size chunks.

POST
Add Watermark/api/v1/pdf/watermark

Add text watermarks with dynamic variables and page targeting.

POST
Remove Password/api/v1/pdf/remove-password

Remove or change PDF password protection.

Analysis & Compliance

POST
PDF Inspection/api/v1/analyze/pdf-inspect

Analyze structure, fonts, images, and optimization opportunities.

POST
PDF/A Validation/api/v1/pdf/validate-pdfa

Check PDF/A-1b, 2b, and 3b compliance.

POST
PDF/A Conversion/api/v1/convert/pdf-to-pdfa

Convert standard PDFs to PDF/A archival format.

OCR

POST
Simple OCR (Tesseract)/api/v1/ocr/extract/simple

Fast, free text extraction. Up to 20 pages sync.

POST
Advanced OCR (DocTR)/api/v1/ocr/extract/advanced

Neural network OCR with word-level bounding boxes. Up to 10 pages sync.

POST
Vision OCR (Claude AI)/api/v1/ocr/extract/vision

Highest accuracy. Handwriting, complex layouts, forms. Up to 3 pages sync.

Platform

GET
Async Jobs/api/v1/jobs

Create, poll, download, and cancel background processing jobs.

GET
Usage Tracking/api/v1/usage

Monitor API consumption with per-request logs and summaries.

Rate Limits

Every response includes rate limit headers:

HeaderDescription
X-RateLimit-LimitMax requests per minute
X-RateLimit-RemainingRequests remaining
X-RateLimit-ResetUnix timestamp for reset
X-Credits-RemainingCredits left on account

Error Codes

Errors return JSON with a detail field:

CodeMeaning
400Bad Request
401Unauthorized
402Insufficient Credits
413Payload Too Large
422Validation Error
429Rate Limit Exceeded
500Internal Server Error

Interactive API Explorer

Try endpoints directly in your browser with the Swagger UI or ReDoc interface.

Swagger UIReDoc