Every newsletter placement gets its own tracking link. See clicks, conversions, and ROAS per send — not just open rates your ESP reports.
UTMs pass through automatically. Promo codes catch readers who convert later.
Unlike podcasts or YouTube, newsletter readers are already in a clicking context. That makes attribution significantly more accurate.
Email readers click links naturally — they are already on a screen with intent to act. Newsletter sponsor link CTR is 3–10x higher than podcast description link CTR.
Newsletter subscribers opted in to receive content in a specific niche. They are warmer audiences than social media followers — leading to higher conversion rates and ROAS.
Most newsletter opens happen within 24–72 hours of send. Conversions follow quickly. You see results within days, not weeks — making it easier to optimize your spend.
A unique tracking link per placement — with UTMs passed through and promo codes as a fallback.
castlytics.app/r/abc123 — one per newsletter, per issue
Every campaign gets a unique short link. Give a different link to each newsletter you sponsor. When readers click, Castlytics records the visit and holds it for conversion matching. Even if the same newsletter runs multiple issues, each gets its own link.
Best for: any clickable placement in email, web archive, or cross-post
utm_source, utm_medium, utm_campaign auto-appended
Castlytics automatically appends UTM parameters to the final destination URL. This means your Google Analytics or Plausible dashboard also sees the source — you get attribution in Castlytics and in your existing analytics stack.
Best for: teams using Google Analytics, Plausible, or Fathom alongside Castlytics
Reader uses MORNING15 at checkout — matched to the campaign
Some readers forward the email, save it for later, or share the promo code with a colleague. A promo code in the newsletter CTA ensures those conversions are still attributed to the placement — even without a link click.
Best for: high-consideration products, B2B newsletters, multi-step funnels
Use these ranges to evaluate whether a placement is performing well — and when to cut or scale.
1–8%
Sponsor link CTR
Niche B2B newsletters top 5–8%. Consumer newsletters average 1–3%.
2–5×
ROAS for niche B2B
High-intent audiences in specific verticals convert at higher rates, driving strong ROAS.
48 hrs
Conversion window peak
Most email-driven conversions happen within 48 hours of send time.
Create a campaign per placement and get a unique link in under 2 minutes.
Paste one script tag into your site's <head>. Captures conversions and matches them to newsletter-driven visitors.
<script src="https://castlytics.app/tracker.js" data-key="YOUR_KEY" async></script>Name the placement (newsletter name + issue date), set a promo code, and get your unique tracking link. Repeat for each placement.
Replace the destination URL in the sponsor brief with your Castlytics tracking link. Include the promo code in the CTA copy. That is all the newsletter needs to run.
Newsletter readers are already on a screen in a clicking context. Links are native and highly visible. This means tracking links capture a much higher share of conversions compared to audio-first channels where listeners cannot click in the moment.
Niche B2B newsletters often see 3–8% CTR on sponsor links. General consumer newsletters average 1–3%. High CTR does not always mean high ROAS — use Castlytics to track what actually converts, not just what gets clicked.
Most newsletter-driven conversions happen within 48–72 hours of send. We recommend a 7-day window as the default. For high-consideration B2B products, extend it to 30 days to catch readers who bookmarked the email and came back later.
Yes. Create a separate campaign for each issue. This lets you compare performance issue-by-issue — useful for understanding whether placement position, copy, or seasonality affects results.
Yes. Castlytics appends UTM parameters to the destination URL automatically. Your Google Analytics or Plausible dashboard will also see the source, so you get attribution in Castlytics and in your existing analytics stack simultaneously.
Free plan includes 3 campaigns, unlimited clicks, and 30-day attribution. No credit card required.
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