Generate PDFs in Ruby
Generate PDFs from HTML, Markdown, URLs or templates in Ruby — using Net::HTTP and the RenderPDFs REST API.
1. Install
RenderPDFs uses a plain REST API — no SDK required. For Ruby, install the dependency below and grab your API key from renderpdfs.com/signup (free, 100 PDFs/month, no credit card).
# Net::HTTP is built into the Ruby stdlib — no install needed
gem install json # only if not already available2. Convert HTML to PDF
The simplest case: send an HTML string, get back a PDF binary. Anything Chromium renders works — Flexbox, Grid, web fonts, SVG, JavaScript.
require "net/http"
require "json"
require "uri"
uri = URI("https://api.renderpdfs.com/v1/generate")
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
req = Net::HTTP::Post.new(uri)
req["X-API-Key"] = ENV["RENDERPDFS_KEY"]
req["Content-Type"] = "application/json"
req.body = { html: "<h1>Hello PDF</h1><p>Generated from Ruby</p>" }.to_json
res = http.request(req)
File.binwrite("hello.pdf", res.body)3. Convert a URL to PDF
Pass url instead of html and RenderPDFs fetches the page, waits for JS, and snapshots it. Useful for archiving dashboards, public pages, or invoices served from your app.
req.body = {
url: "https://example.com",
options: { format: "A4", printBackground: true },
}.to_json
res = http.request(req)
File.binwrite("page.pdf", res.body)4. Use a built-in template
Skip the design work. RenderPDFs ships six battle-tested templates — invoice, receipt, report, contract, certificate, offer_letter. Send JSON, get a styled PDF.
req.body = {
template: "invoice",
data: {
company: "Acme Inc.",
invoice_number: "INV-001",
items: [
{ description: "Consulting", quantity: 10, unit_price: 120 },
],
},
}.to_json5. Custom paper, margins, headers
Control page format, orientation, margins, and running headers/footers via the options object. All standard Chromium PDF settings are supported.
req.body = {
html: "<h1>Report</h1>",
options: {
format: "Letter",
landscape: false,
margin: { top: "20mm", bottom: "20mm", left: "15mm", right: "15mm" },
printBackground: true,
},
}.to_json6. Store the PDF and share a link
For emailable links or webhook payloads, set store: true in the body. The response becomes { url, expires_in } — the PDF is hosted on our CDN for 24 hours by default.
req.body = { html: "<h1>Shared report</h1>", store: true }.to_json
result = JSON.parse(http.request(req).body)
puts "Download at #{result['url']} (expires in #{result['expires_in']}s)"7. Notes & gotchas
Every request needs an X-API-Key header. Grab a free key at renderpdfs.com/signup — 100 PDFs/month, no credit card. Treat the key like a password: keep it server-side, never expose it in browser code.
By default the endpoint streams back the raw PDF binary (Content-Type: application/pdf). Set `store: true` in the body and the response becomes { url, expires_in } — useful for emailing links or attaching to webhooks.
Non-2xx responses return JSON: { error: string }. The most common cases are 401 (bad API key), 402 (over plan quota), and 422 (invalid HTML or URL). Always parse the error body before retrying.
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Generate your first PDF in 60 seconds
100 free PDFs per month. No credit card. HTML, Markdown, URLs, templates, MCP — all included.