API Reference - LaTeXLite Docs

POST /v1/renders-sync

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)

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

POST /v1/math-sync

Render a LaTeX math expression to PNG. The math string must start and end with $ or $$. Returns image/png by default.

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:

Content-Type	Use case	Data injection
application/json	Inline template string	Via `data` field
text/plain text/x-tex application/x-tex	Raw .tex file upload	None (self-contained)
multipart/form-data	.tex file with placeholders	Via `data` form field (JSON string)

Template Syntax

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

Simple field

[[.FieldName]]

Loop over a list

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

Corresponding data

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

Note: When writing JSON inline in curl, backslashes must be doubled: \int becomes \\int. However \n and \t are JSON escape sequences and remain single backslash.

HTTP Status Codes

Status	Meaning
200	OK — request successful
400	Bad Request — invalid template or data
401	Unauthorized — missing or invalid API key
408	Request Timeout — render timed out
422	Unprocessable Entity — LaTeX compilation failed
429	Too Many Requests — rate limit exceeded
502	Bad Gateway — renderer service error
503	Service Unavailable — renderer not configured

Request Limits

/v1/renders-sync

Max body size: 1 MiB
Max template size: 200 KB
Timeout: 8 seconds
Max PDF size: 20 MB

/v1/math-sync

Max body size: 64 KiB
Max math input: 32 KB
Timeout: 8 seconds

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

Rate Limits

Rate limit state is communicated via response headers:

Header	Description
X-RateLimit-Limit	Maximum requests allowed per minute
X-RateLimit-Remaining	Requests remaining in current window
X-RateLimit-Reset	Unix timestamp when the limit resets