Last spring a client asked me to announce a new quoting tool to their sales team. Forty reps, one feature that would save each of them about an hour a week. I wrote a clear, friendly, plain-text email and sent it on a Tuesday morning.
By Friday, six people had opened it. Nobody replied. The next week two reps asked their manager whether the new tool was "a thing yet."
The email wasn't wrong. It just looked like every other email in their inbox, and the inbox is where announcements go to be archived.
A hundred pages from a hundred prompts
Around the same time, Mia (@MiaAI_lab) posted a gallery of 100 web pages that Claude built, each from one prompt. A brass orrery with the planets in their real positions for today's date. A chess set on a leather desk that you can actually play. A paper crane you fold step by step. Every one is a single HTML file with nothing loaded from anywhere else, and no two look alike.
One hundred pages, one prompt each
Every stamp opens its piece in Mia's gallery. Open one, then press its Prompt button to see exactly what produced it.
Collected by Mia (@MiaAI_lab) in September 2026. Browse the whole gallery.
I spent an evening clicking through them, and the obvious thought landed: an email is just a small HTML file. If Claude can build an orrery, it can build an announcement that looks worth announcing.
So I rewrote the quoting-tool email as a designed one. A bold header in the client's colors, one picture of the new screen, three short sections and one button. It took about twenty minutes, most of it me fussing over the headline. I sent it to the same forty reps.
Three of them replied within the hour asking for a demo.
Same news, two envelopes
Drag to compare the email I sent first with the one I sent second. Same facts, same forty reps. Halvard Supply is a stand-in for the real client.
Plain email is still the right tool for most of what I send. But when I need people to actually read something (a launch, an announcement, anything that's really marketing), a designed email earns its place. It can be beautiful, and beautiful stands out in an inbox full of gray text.
With AI it's easier than ever to make one. Claude writes the HTML file, you save it on your computer and double-click it, and you're looking at your email in the browser before anyone else sees it. The hard part is the last mile: getting that file into your email program without mangling it, so it lands cleanly in other people's inboxes. That's most of what follows.
How to make one
You don't need a designer or a marketing platform for a one-off. You need Claude, a browser and about twenty minutes.
- 1.
Write the message first, in plain words. Design can't rescue a vague message. Know the one thing you want the reader to do before anything gets colorful.
- 2.
Borrow a look. Open the gallery and find a piece whose mood fits your message. Each one has a Prompt button that shows exactly what produced it, and you can view the source of any page. Paste either into Claude and say, "Use this as visual inspiration for an email." You're borrowing a palette, a feel for type and a sense of composition, not the page itself.
- 3.
Tell Claude it's an email. This is the step people skip. Email programs are years behind web browsers, and a page that looks stunning in Chrome can fall apart in Outlook. Paste something like this alongside your message:
Build this as an HTML email, not a web page. One centered column 600 pixels wide, laid out with tables, every style inline. No JavaScript and no external stylesheets. Use web-safe fonts with fallbacks. Make the button a styled table cell with a link, not an image. Every image needs a public URL, a width and alt text. It has to read well on a phone and in dark mode, and stay under 100 KB.
That last number matters. Gmail clips any message over about 102 KB and hides the rest behind a "View entire message" link.
- 4.
Look at it, then tighten. Ask Claude to show it as an artifact, or save the file and open it in your browser, and narrow the window to phone width. Ask for changes the way you'd talk to a designer: the header is too tall, make the button the client's green, cut the third section.
- 5.
Put it in your drafts. Claude hands you a file, and this is where most designed emails get ruined. Attach the file and your readers get a download instead of a message. Paste it the wrong way and the colors and layout fall off. The clean route depends on what you send from.
- Apple Mail. Open the file in Safari, then choose File, Share, Email This Page. The design arrives as a new message you can address and edit.
- Gmail. Open the file in Chrome, select everything on the page, copy it and paste it into a new message. Inline styles survive the paste, which is why step 3 asks for them.
- Outlook for Windows. Start a new message, choose Insert, then Attach File, and pick the HTML file. Instead of clicking Insert, open the arrow beside it and choose Insert as Text.
- A coding agent. If you use Claude Code, ask it to put the email straight into your Gmail drafts through the Gmail API. It writes the short script, and you still read the draft in Gmail before anything goes out.
- A whole list. Most email marketing tools have a "paste your own code" template. Paste the HTML there and let the tool handle the unsubscribe link and the sending.
Five routes from a file to your drafts
Pick where you send from.
Whichever route you take, send it to yourself first.
- 6.
Send it to yourself first. Open it in Gmail and Outlook, on your phone, and once in dark mode. Images are the usual casualty. A picture sitting on your laptop doesn't travel with the email, so it has to live at a public web address. When in doubt, ask Claude to do the decorating with color and type instead of pictures. That never breaks.
Then it had to happen every week
The one-off worked well enough that the client asked for one with every release. That's where the twenty-minute method started to strain.
By the fourth email I was re-pasting the same footer, hunting for the unsubscribe link, re-uploading screenshots and re-explaining the client's voice to a fresh Claude chat. Each email came out a little different from the last. The only review step was me squinting at a draft before my first coffee.
So I built the repeatable version into Prosperion, the content platform we run our own marketing on and our clients run theirs on.
- The brand is written down once. Each organization has a brand guide (voice, audience, the words it never uses) that the drafting agent reads every time. I stopped re-explaining.
- A draft is only the message. The greeting, signature, footer, unsubscribe link and any required disclosures come from the organization's settings and wrap every email the same way. Nobody pastes a footer again.
- Screenshots go up once. They upload to hosted storage at email width, so they show up in every inbox.
- A person approves before anything sends. Drafts wait for review. For our financial advisory clients, a compliance reviewer signs off first. A draft existing never means a draft goes out.
- Each audience gets its own email. Lists and segments live in Prosperion, so the same news can go to exactly the people it matters to.
That last one changed release notes for me. When we ship a release of one client's platform, the release note gets written as part of shipping it. Prosperion turns that one note into a separate email for each team. The release this week had thirteen changes. The admins' email covers all thirteen. The quoting team's covers twelve, the sales reps' covers eight, and the service team's has exactly one, because only one change touched their work. Each lands in my review queue as a draft with its screenshots in place, and I read four short emails instead of writing them.
The sorting office
One release note in, one draft per team out. Nothing leaves until a person stamps it.
One release note, thirteen changes, and four teams who each care about some of them.
It turns out people read release notes when the release notes are about them.
Start with one
You don't need any of the platform to start. This week, write one email you'd actually want to open. Pick a piece from the gallery, tell Claude it's building an email, and send it to yourself before anyone else.
If your team sends the same kind of email every week and it's starting to feel like a chore, that's what we built Prosperion for. Schedule a free Discovery Session at keyelement.ai and I'll show you how it runs ours.
Let’s build something.
A free working call, not a pitch. Bring the email you keep rewriting every week.
Halvard Supply and Quick Quote are fictional stand-ins. Gallery pieces belong to their creator and open on her site.