Best Newsletters for Side Hustles and AI Tool Sponsorships: beehiiv vs Substack for Monetized Newsletters 

beehiiv is the better choice for a side hustle newsletter built around AI tool sponsorships, while Substack is better for writers who want the simplest paid newsletter setup. If your goal is to sell ad spots to AI SaaS brands, track clicks, grow with referrals, and package your audience like a media asset, beehiiv gives you more room to operate.

TLDR: Choose beehiiv if you want sponsorships, growth tools, audience segmentation, and ad-friendly analytics. Choose Substack if you want to publish fast, charge readers, and avoid fiddly setup. For example, a weekly AI tools newsletter with 5,000 subscribers and a 45% open rate could pitch sponsors on roughly 2,250 opens per issue; beehiiv makes that easier to package, while Substack makes publishing the issue easier. If you earn $2,000 per month from paid readers, Substack takes 10%, while beehiiv charges no platform cut but requires a paid software plan for many monetization features.

Why AI Tool Newsletters Are a Strong Side Hustle

AI tool newsletters work because the reader has a clear intent: save time, find useful apps, and avoid wasting money on overhyped software. That makes the audience attractive to sponsors. AI writing tools, automation platforms, coding assistants, meeting bots, design apps, and sales tools all want access to people who test products early.

The format is also simple. A strong issue might include:

• One featured AI tool with a short review.
• Three quick finds for productivity, marketing, or coding.
• A sponsored slot clearly marked as paid.
• A short tutorial showing a real workflow.
• A reader poll to collect buying intent.

This is why platform choice matters. A personal essay newsletter and a sponsorship-driven AI newsletter do not need the same machine behind them.

beehiiv: Built for Growth and Sponsorship Revenue

beehiiv feels built for people who treat a newsletter like a small media company. It gives you publishing tools, a website, email capture forms, referral programs, audience segments, automations, and monetization tools in one place.

The biggest reason side hustlers like beehiiv is the growth engine. You can create referral rewards, recommend other newsletters, run audience surveys, and track performance without stitching together five tools. That matters when you are working nights and weekends. Nobody wants their “simple side project” to turn into a pile of browser tabs.

For sponsorships, beehiiv has a clear edge. Its ad network can connect eligible newsletters with sponsors. You can also sell your own placements and support them with useful metrics, such as opens, clicks, subscriber growth, and engagement by segment. If you write about AI tools for founders, marketers, or developers, those segments matter. An advertiser will pay more for 3,000 startup founders than for 30,000 random inboxes.

The catch is… beehiiv can feel busy at first. Some settings sit deeper than expected, and setting up automations or referral rewards may take more clicks than a beginner wants. Expect to spend a few hours getting the account, domain, forms, and monetization setup right. After that, it becomes a very capable system.

Substack: Simple, Fast, and Reader Friendly

Substack wins on ease. You can start writing, publish to email and web, and turn on paid subscriptions quickly. The editor is clean. The reading experience is familiar. The social features help readers comment, like, share, and discover other writers.

Substack is especially strong if your side hustle is built around your voice. If you write sharp analysis about AI trends, weekly tool reviews, or opinionated breakdowns of new product launches, Substack can work well. Readers often subscribe because they like the person behind the publication.

Substack also has a recommendation system. Other writers can recommend your publication, and that can send meaningful subscriber growth if your topic fits their audience. For solo creators, this is appealing. You are not starting from a blank page.

But for AI tool sponsorships, Substack feels limited. You can sell ads manually, sure. You can add sponsor copy into posts. Yet you do not get the same built-in sponsorship workflow, advanced segmentation, or growth mechanics. Honestly, it feels like Substack wants you to earn from readers first and sponsors second.

Monetization: Paid Readers vs Sponsors

The key question is not “Which platform is better?” It is “How do you plan to make money?”

If you want reader revenue, Substack is hard to beat. You can charge $5, $10, or $15 per month and place premium content behind a paywall. The downside is the 10% platform fee, plus payment processing. That is not painful at $100 per month. It stings more at $5,000 per month.

beehiiv has no platform fee on subscription revenue, but many serious features sit behind paid plans. So the math changes by stage. At low revenue, Substack may be cheaper. At higher revenue, beehiiv can keep more money in your pocket.

For sponsorship revenue, beehiiv is stronger. AI tool brands usually care about email performance, audience quality, and click intent. beehiiv makes it easier to show those numbers. You can build a sponsor page that says, for example: “12,400 subscribers, 41% average open rate, 3.8% average click rate, 68% founders and marketers.” That is a much better sales asset than “I have a newsletter.”

Which Platform Fits Each Side Hustle?

Pick beehiiv if your newsletter is one of these:

• AI tools directory newsletter: weekly tool rankings, discounts, and tutorials.
• Founder productivity newsletter: automation workflows and SaaS recommendations.
• Marketing AI newsletter: prompts, campaign ideas, and creative software reviews.
• B2B tech digest: sponsor-friendly and focused on decision makers.

Pick Substack if your newsletter is closer to these:

• Personal AI essays: analysis, opinions, and predictions.
• Paid research notes: premium posts for loyal readers.
• Creator-led commentary: your personality is the main product.
• Community writing: discussion threads and reader replies matter most.

Analytics and Sponsor Reporting

Sponsors do not want vague promises. They want numbers. This is where beehiiv has a practical advantage.

A good sponsor report should include:

• Total sends for the sponsored issue.
• Open rate and unique opens.
• Click count on the sponsor link.
• Click through rate for the placement.
• Audience notes, such as job roles or interests.

With beehiiv, this type of reporting feels more natural. With Substack, you can still pull useful numbers, but sponsorship reporting is not the main focus. It drives me crazy that simple creator tools often treat advertisers like an afterthought. If you are taking real sponsor money, you need clean reporting.

Growth Tools: Where beehiiv Pulls Ahead

Growth is the hard part. Writing is only half the game. You also need people to find the newsletter, trust it, and share it.

beehiiv gives you more tools for that job. Referral programs can reward readers for sharing. Signup forms can be placed across landing pages. Audience polls can help qualify subscribers. Automations can welcome new readers and pitch a paid product or sponsor offer later.

Substack growth is more social. Recommendations, notes, comments, and writer networks can drive discovery. That is useful, but less controlled. You may get a burst of subscribers from a recommendation, then nothing for weeks. Great when it works. Annoying when it does not.

Pricing: The Quick Read

Substack is attractive because it costs nothing to start. You pay when you earn from subscriptions. That makes it beginner friendly. If your newsletter never makes money, you do not lose money on software.

beehiiv can cost more upfront, especially when you want advanced growth and monetization features. But it can make more sense once your newsletter becomes a real asset. If you plan to sell sponsorships, build segments, and optimize growth, the software cost can be worth it.

Final Recommendation

If your main goal is AI tool sponsorships, choose beehiiv. It gives you better tools for growth, sponsor packaging, analytics, and long-term monetization. It is the stronger pick for a side hustle that you want to turn into a media business.

If your main goal is paid writing, choose Substack. It is easier, cleaner, and faster for publishing to a loyal audience. Just remember that the 10% fee becomes more noticeable as revenue grows.

The smartest path for many creators is simple: start where your monetization model fits. For ad sales and AI tool sponsors, beehiiv wins. For paid essays and reader-funded writing, Substack still makes a lot of sense.