Can I attach the certificate image to an email?

Yes. The API returns a base64-encoded image you can attach directly to transactional emails via SendGrid, Postmark, or similar, or upload to S3/Google Drive first and include the URL. Most LMS platforms accept base64 attachments or hosted image URLs.

Certificate Generator API — Bulk Certificates, Free Tier

Who Uses This

Certificates for every use case

🎓

Online Courses

Auto-generate completion certificates when students finish a course. Integrate with your LMS — Teachable, Thinkific, or custom platforms.

🏆

Events & Conferences

Bulk-generate attendance certificates for hundreds of participants. Upload a CSV, loop through names, and get images back in seconds.

💼

Employee Recognition

Award certificates for training completion, performance milestones, or internal programs. Integrate with HR tools via API.

How It Works

HTML in, certificate image out

generate-certificate.js

// Generate a course completion certificate
const html = `
  <div style="width:1400px;height:1000px;background:white;display:flex;
    flex-direction:column;align-items:center;justify-content:center;
    border:12px solid #1e293b;padding:60px;font-family:Georgia,serif">
    <div style="font-size:18px;letter-spacing:6px;color:#64748b">
      CERTIFICATE OF COMPLETION
    </div>
    <div style="width:120px;height:2px;background:#22d3ee;margin:24px 0"></div>
    <div style="font-size:48px;color:#0f172a;margin:20px 0">
      ${recipientName}
    </div>
    <div style="font-size:18px;color:#475569;max-width:600px;text-align:center">
      has successfully completed the course
      <strong>${courseName}</strong>
      on ${completionDate}
    </div>
  </div>
`;

const res = await fetch('https://renderpix.dev/v1/render', {
  method: 'POST',
  headers: { 'X-API-Key': 'rpx_your_key', 'Content-Type': 'application/json' },
  body: JSON.stringify({ html, width: 1400, height: 1000, format: 'png' })
});

const certImage = await res.arrayBuffer();

Why renderpix

Built for bulk certificate generation

✓

Full CSS support

Custom fonts, borders, gradients, images, logos — real Chromium rendering means your certificates look exactly as designed.

✓

Bulk-friendly pricing

Generate 50,000 certificates/month for $79. That's $0.0016 per certificate — cheaper than any alternative.

✓

PNG, JPEG, or WebP

Choose the format that fits. PNG for print-quality certs, JPEG for email attachments, WebP for web display.

✓

Retina / 2x output

Set scale=2 for high-DPI certificate images that look crisp when printed on paper.

New in June 2026

Now with batch rendering & template variables

Automate at scale without writing a loop.

Batch Rendering

Render up to 50 images in a single API call (Pro plan). Generate an entire week's content in one request.

Issue 200+ certificates the moment a course ends. Batch render all students in one request, zip and email in minutes.

Template Variables

Use {{placeholders}} in your HTML. Inject names, dates, titles dynamically — no string manipulation in your code.

{{name}}, {{course}}, {{date}}, {{instructor}} — one HTML template handles every student automatically.

Async Callbacks

Fire-and-forget rendering with callback_url. Your app doesn't wait — RenderPix calls you back when the image is ready. (Pro+)

Trigger certificate generation on course completion webhook. Your LMS gets a 200 immediately; student receives email when render completes.

batch-certificates.js

// Batch generate certificates for all students
const students = [
  { name: 'Jane Smith', course: 'Advanced n8n', date: 'June 2026' },
  { name: 'John Doe',   course: 'Advanced n8n', date: 'June 2026' },
];

const response = await fetch('https://renderpix.dev/v1/batch', {
  method: 'POST',
  headers: { 'X-API-Key': 'rpx_your_key', 'Content-Type': 'application/json' },
  body: JSON.stringify({
    items: students.map(s => ({
      html: `<div style="width:1200px;height:850px;background:white;display:flex;
        flex-direction:column;align-items:center;justify-content:center;
        border:20px solid #0f172a;font-family:Georgia,serif;padding:60px">
        <div style="font-size:18px;color:#64748b;letter-spacing:4px">CERTIFICATE OF COMPLETION</div>
        <div style="font-size:56px;font-weight:700;color:#0f172a;margin:24px 0">{{name}}</div>
        <div style="font-size:20px;color:#64748b">has successfully completed {{course}}</div>
        <div style="font-size:16px;color:#94a3b8;margin-top:32px">{{date}}</div>
      </div>`,
      vars: { name: s.name, course: s.course, date: s.date },
      width: 1200, height: 850, format: 'png'
    }))
  })
});
const { results } = await response.json();
// results[i].image = base64 PNG for each student

Template Variables

One template, every student

Write {{name}}, {{course}}, {{date}} in your HTML. Pass a vars object in the request body. RenderPix substitutes them before rendering — no string manipulation needed in your code.

curl — /v1/render with vars

# Single certificate with template variables
curl -X POST https://renderpix.dev/v1/render   -H "X-API-Key: rpx_your_key"   -H "Content-Type: application/json"   -d '{
    "html": "<div style=\"width:1200px;height:850px;background:#fff;display:flex;flex-direction:column;align-items:center;justify-content:center;border:20px solid #0f172a;font-family:Georgia,serif;padding:60px\">\n  <div style=\"font-size:16px;letter-spacing:4px;color:#64748b\">CERTIFICATE OF COMPLETION</div>\n  <div style=\"font-size:52px;font-weight:700;color:#0f172a;margin:24px 0\">{{name}}</div>\n  <div style=\"font-size:18px;color:#475569\">has completed <strong>{{course}}</strong></div>\n  <div style=\"font-size:14px;color:#94a3b8;margin-top:28px\">{{date}}</div>\n</div>",
    "vars": { "name": "Jane Smith", "course": "Advanced n8n", "date": "June 2026" },
    "width": 1200,
    "height": 850,
    "format": "png",
    "scale": 2
  }'
# Returns base64 PNG at 2400x1700px — print-ready, ready to attach to email

Automation

Plug into your no-code stack

RenderPix has a native n8n node. Chain it with any trigger — form submission, LMS webhook, Zapier step, or Make scenario.

STEP 1

Form / LMS Trigger

Student completes a course or submits a registration. Typeform, Tally, Teachable webhook, or any HTTP trigger.

→

STEP 2

RenderPix n8n Node

HTML certificate template with {{name}} {{course}} {{date}} vars mapped from the trigger output.

→

STEP 3

Email or Drive

Attach the PNG certificate to a transactional email via SendGrid or Postmark, or upload to Google Drive for record-keeping.

Works the same way in Zapier and Make — use the HTTP Request module with your API key and vars object.

Examples

Certificate examples

Certificates generated with RenderPix — custom fonts, layouts, and colors, all from HTML/CSS templates.

Course Completion

Conference attendance certificate example generated by RenderPix

Event Attendance

Employee Training

Skill Badge

FAQ

Frequently asked questions

Does RenderPix generate PDF certificates?

RenderPix returns PNG, JPEG, or WebP images. To deliver a PDF, render your certificate as a high-res PNG (scale=2 for print quality) then embed it into a PDF using any library — jsPDF, PDFKit, Python-pdfkit, or similar. The image quality is indistinguishable from a native PDF rendering.

How many certificates can I generate at once?

On the Pro plan you can batch up to 50 certificates in a single API call. For larger runs, fire multiple requests concurrently or use the async callback endpoint so your application is not blocked waiting for each batch to complete.

Can I use custom fonts and logos?

Yes. RenderPix uses headless Chromium, so any font reachable via a CSS @font-face URL (Google Fonts, CDN, or base64-inlined) and any image URL accessible on the internet will render exactly as designed.

Is there a free plan?

Yes. The free plan includes 100 renders per month with no credit card required — enough to build and test your full integration before going to production.

Does it work with n8n, Zapier, or Make?

Yes. RenderPix has a native n8n node, and works with Zapier and Make via HTTP request modules. Use {{name}}, {{course}}, {{date}} template variables in your HTML and pass a vars object populated from your workflow trigger.

Can I attach the certificate to an email?

Yes. The API returns a base64-encoded image you can attach directly to transactional emails via SendGrid, Postmark, or similar services, or upload to S3/Google Drive first and include the URL. Most LMS platforms accept base64 attachments or hosted image URLs.