by Chris McConnell

How I Added Dynamic LinkedIn Certifications to PostHog's Post-it Training

How I Added Dynamic LinkedIn Certifications to PostHog’s Post-it Training

How I Added Dynamic LinkedIn Certifications to PostHog’s Post-it Training

A technical deep-dive into implementing LinkedIn’s Add-to-Profile API for dynamic professional certifications

The Challenge

PostHog has a hilarious “Post-it Training Academy” that teaches proper sticky note technique. It’s a fun internal training that ends with users getting “Post-it certified” - but the LinkedIn sharing button just linked to a generic certification form.

The goal: Replace that static link with a dynamic “Add to Profile” button that creates actual LinkedIn certifications with current dates and unique IDs.

The Technical Implementation

<CallToAction
    href="https://www.linkedin.com/in/me/edit/forms/certification/new/"
    type="primary"
>
    <>Share on LinkedIn</>
</CallToAction>

After: Dynamic Certification Generator

// LinkedIn certification URL generation  
const now = new Date()
const issueYear = now.getFullYear()
const issueMonth = now.getMonth() + 1  // JS months are 0-indexed 🤮
const expirationYear = issueYear + 100
const expirationMonth = issueMonth
const liUrl =
    `https://www.linkedin.com/profile/add?` +
    new URLSearchParams({
        startTask: 'CERTIFICATION_NAME',
        name: 'Post-It Note Certified Applicator',
        organizationId: '37415928',
        organizationName: 'PostHog', 
        issueYear: String(issueYear),
        issueMonth: String(issueMonth),
        expirationYear: String(expirationYear),
        expirationMonth: String(expirationMonth),
        certUrl: 'https://www.posthog.com',
        certId: String(Date.now() + Math.random() * 1000), // Always unique
    }).toString()

<CallToAction href={liUrl} type="primary">
    <>Add to LinkedIn Profile</>
</CallToAction>

Key Technical Decisions

1. No React State Needed

Initially considered useState for incrementing certification IDs, but realized a simpler approach works better:

  • Date.now() + Math.random() * 1000 generates unique IDs every time
  • No state management complexity
  • Each user gets a truly unique certification

2. JavaScript Date Quirks

JavaScript’s getMonth() returns 0-11 instead of 1-12, so we add +1 to get human-readable months. August = 7 + 1 = 8. One of those “why JavaScript, why?” moments.

3. URLSearchParams for Clean Encoding

Using URLSearchParams handles proper URL encoding automatically instead of manual string concatenation and encoding.

4. 100-Year Expiration

Set certifications to expire in 2125. Because Post-it skills are timeless.

The Result

Now when users complete the training, they can click “Add to LinkedIn Profile” and get a properly formatted certification that shows:

  • Name: “Post-It Note Certified Applicator”
  • Organization: PostHog
  • Issue Date: Current month/year
  • Unique ID: Timestamp + random number
  • Expires: 100 years later

Lessons Learned

  1. Keep it simple: Dynamic doesn’t always mean complex state management
  2. JavaScript dates are cursed: That +1 for months will forever be annoying
  3. URLSearchParams is your friend: Let the browser handle URL encoding
  4. Unique IDs are easy: Timestamp + random number works great for non-sequential IDs

The entire implementation was just 15 lines of clean JavaScript - no frameworks, no state, just dynamic URL generation that creates real LinkedIn certifications.

Want to see this in action? Check out PostHog’s Post-it Training Academy and get yourself certified! 📝

Technical specs:

  • React/TypeScript
  • Gatsby framework
  • LinkedIn Add-to-Profile API
  • Zero additional dependencies
← Back to Writing