API Reference

Render a LaTeX template to PDF. Returns application/pdf by default. Set Accept: application/json to receive a base64-encoded PDF instead.

Request (JSON)

{
  "template": "\\documentclass{article}\n\\begin{document}\nHello [[.Name]]!\n\\end{document}",
  "data": {
    "Name": "World"
  }
}

Response (application/pdf)

PDF binary bytes. Use -o output.pdf with curl.

Response (application/json)

Full-quality PDF (HTTP 200):

{
  "success": true,
  "render_status": "OK",
  "data": {
    "content_type": "application/pdf",
    "pdf_base64": "JVBERi0xLjQKJeLjz9MK..."
  }
}

Watermarked PDF (HTTP 201):

{
  "success": true,
  "render_status": "WATERMARKED",
  "data": {
    "content_type": "application/pdf",
    "pdf_base64": "JVBERi0xLjQKJeLjz9MK...",
    "watermark": {
      "reason": "demo_quota_exceeded",
      "message": "You have reached your demo usage limit. Open your account page to upgrade to pro tier for a higher allowance.",
      "account_url": "https://latexlite.com/account"
    }
  }
}

Render a LaTeX math expression to PNG. The math string must start and end with $ or $$. Returns image/png by default. Math PNG output is not watermarked.

Request (JSON)

{
  "math": "$\\int_0^1 x^2 \\, dx = \\frac{1}{3}$"
}

Response (image/png)

PNG binary bytes. Use -o equation.png with curl.

Response (application/json)

{
  "success": true,
  "data": {
    "content_type": "image/png",
    "png_base64": "iVBORw0KGgoAAAANSUhEUgAA..."
  }
}

Supported Content Types

For /v1/renders-sync:

Template Syntax

Templates use Go's text/template syntax with [[ ]] delimiters.

[[.FieldName]]

[[range .Items]][[.Description]] & [[.Qty]] & [[.Total]] \\
[[end]]

{
  "Items": [
    { "Description": "Web Design", "Qty": "1", "Total": "£2,500" }
  ]
}

HTTP Status Codes

Request Limits

Error Handling

All error responses follow this structure:

{
  "success": false,
  "error": {
    "message": "LaTeX compilation failed: ! Undefined control sequence.",
    "line": 0
  }
}

Common Error Messages

• Missing or invalid Authorization header — 401
• Invalid API key — 401
• API key rate limit exceeded. Try again in 1 minute. — 429
• IP rate limit exceeded. Maximum 50 requests per minute per IP. — 429
• missing required field: template — 400
• template too large (max 200KB) — 400
• LaTeX compilation failed: ... — 422
• render timed out. Try optimizing your template. — 408
• math must start and end with $ (or $$) — 400

Usage tiers

Per-account limits depend on subscription state. Defaults (overridable per user in the database):

• Demo / inactive: 10 requests/minute, 50 requests/month.
• Pro: 60 requests/minute, 10000 requests/month.
• Monthly cap on PDF renders: further POST /v1/renders-sync calls return HTTP 201 with a watermarked PDF (not 429). Demo keys get demo_quota_exceeded in API metadata; other tiers get monthly_quota_exceeded. Wait for reset or upgrade tier via your account.

Rate Limits

Rate limit state is communicated via response headers: