Question: Is there a tool that allows me to write and design newsletters in a flexible and customizable way?

If you want a newsletter tool that's flexible and can be customized to your liking, Notocat is a great option. Built on the Notion productivity tool, you can create, manage and send newsletters within the Notion interface. Notocat has templates, multimedia support, customization options, and tracking for opens and clicks, custom sign-up forms and scheduled email sending. It also supports custom domains for better deliverability and has flexible pricing options, including a free trial.

Another option is Mailercloud, an all-in-one email marketing tool. It's got a drag-and-drop template builder, custom HTML editing and advanced reporting with open and click tracking. Mailercloud also has automated campaigns, autoresponders and A/B testing, so it's a good option for newsletter management. It's got a free plan with 12,000 emails per month and a premium plan starting at $10 per month.

If you're interested in AI-powered tools, Bloom is worth a look. It uses AI to help you create and style newsletters that are tailored to your audience. Bloom automates much of the manual work, letting you personalize content quickly while keeping control. It's geared for real estate agents and small business owners, with a subscription-based model to use its features.

Last, Mailsplash is an AI-powered tool for e-commerce brands, with retention-focused templates and customizable graphic design elements. It's designed to save you time and money on email marketing by rapidly creating attention-grabbing emails that fit your brand's style. Mailsplash has three pricing tiers, so it's an option for freelancers and small agencies.