Your newsletter grows on autopilot
An AI agent that watches your RSS feed, converts every edition into social posts, schedules them at peak times, and publishes across X & LinkedIn — while you sleep.
New edition detected
Generated 6 posts
Scheduled across 5 days
Auto-publishing enabled
I've worked with 200+ SaaS founders.
The #1 thing that kills startups?
It's not the product.
It's not the market.
It's building without talking to users...
After mentoring 200+ founders, here are the 5 mistakes that kill SaaS startups:
1. Building without user interviews
2. Scaling before PMF
3. Ignoring churn signals...
45.8K
Impressions
+32%
+247
New Followers
+18%
4.7%
Engagement
+0.8%
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Everything newsletter creators need to grow
Analytics, AI content, and automation — all in one place
Set it once. It runs forever.
Connect your newsletter RSS feed and flip on Agent Mode. Letterly monitors every new edition, generates a week of social posts in your voice, schedules them, and publishes — completely hands-free.
RSS Auto-Detection
The agent watches your feed and triggers automatically every time you publish a new edition
Zero-Touch Publishing
In full auto mode, posts go live without any input from you — or review first in the queue before approving
Configurable Automation Level
Choose full auto, review-before-publish, or manual — you control how much the agent does
Agent Activity
Running24
Editions processed
167
Posts published
48h
Hours saved
Your Writing Persona
Analyzed from 120 posts
AI-generated draft
Matches your persona
I spent 3 years getting this wrong. Here's what finally clicked about growing a newsletter past 10K subscribers without burning out.
Content that sounds exactly like you
Letterly analyzes your existing posts to build a deep persona — your tone, hook patterns, length preferences, CTA style. Every generated post is indistinguishable from something you'd write yourself.
Deep Persona Analysis
Scan your LinkedIn or X profile to extract your writing fingerprint — tone, rhythm, vocabulary, and structure
Model Any Creator
Build personas from any public LinkedIn or X profile to draw inspiration from creators whose style resonates with you
Consistent Across Platforms
The same authentic voice across X threads, LinkedIn posts, and every platform — no manual rewriting
Stay in control. Track everything.
Review AI-generated posts before they go live, monitor follower growth across platforms, and see exactly which content drives newsletter conversions.
Post Review Queue
See every pending post, approve or edit in one click, or let the agent auto-approve and publish on schedule
Unified Growth Dashboard
Track X and LinkedIn follower growth, post impressions, engagement rate, and newsletter subscriber trends in one view
CTA Conversion Tracking
See which social posts drive the most newsletter sign-ups with link-level click tracking and conversion attribution
Review Queue
3 pending5 brutal truths about SaaS that nobody talks about. I learned these the hard way...
The biggest mistake early-stage founders make with pricing (and how to fix it)
Your newsletter is your most underrated growth asset. Here's why...
X
4,821
+214
2,340
+118
How It Works
From setup to autopilot in under 10 minutes
Connect your newsletter RSS feed
Paste your newsletter RSS URL — Substack, Beehiiv, Ghost, ConvertKit, or any platform. Letterly starts monitoring it immediately and detects every new edition you publish.
- Works with Substack, Beehiiv, Ghost, ConvertKit & more
- Auto-detects new editions as soon as you publish
- One-time setup, runs forever after that
Feed connected
Last edition: 2 days ago · Monitoring active
Substack
Beehiiv
Ghost
Persona Setup
AI AnalysisPersona built from 94 posts
Persona saved — agent will use this voice
Build your AI persona
Point Letterly at your LinkedIn or X profile and it analyzes your existing posts to capture your unique writing voice — hook style, tone, length, vocabulary. Every generated post sounds like you wrote it.
- Analyze your own profile for your exact voice
- Or model any creator whose style you admire
- Multiple personas — switch per post type
- Fine-tune with attitude, CTA frequency & more
Turn on Agent Mode
Flip the switch and Letterly's agent takes over. Every time you publish a newsletter, it automatically generates posts, fills your content calendar, and publishes at optimal times.
- Full auto: publish without lifting a finger
- Review mode: approve each post before it goes live
- Configure post frequency and scheduling windows
- Supports X threads and long-form LinkedIn posts
Agent Settings
ActiveAgent generated 6 posts from your latest edition
Scheduled Mon–Sat · No action needed
Growth Dashboard
Newsletter subs
3,240
+14% this month
X followers
4,821
+9% this month
Impressions
52K
+27% this month
CTA clicks
1,580
+19% this month
Watch your audience grow
Track follower growth, post performance, and newsletter conversions all in one dashboard. See exactly which posts drove sign-ups, so you can double down on what works.
- X and LinkedIn follower growth charts
- Post impressions and engagement tracking
- CTA click attribution to newsletter sign-ups
- Weekly digest of your top-performing content
Loved by creators worldwide
Join newsletter creators who trust Letterly to grow their audience
"It's like hiring a junior content manager who does 90% of the work, but you always get the final say."
ChatGPT
LLM
"You're a fucking genius and I love you."
Affectionate-Turn495
Reddit User
"The service you provide is a great idea. I've always thought i'd love to help our SEO clients turn the articles we create for them into social posts as well."
Rob Hoffman
CEO @ Contact.so | Mentions.so | Kleo.so
"Letterly turned my newsletter into a real growth engine. I went from posting randomly to having a full weekly plan that actually performs."
Letterly User
Newsletter Creator
"I used to spend hours rewriting my newsletter for socials. Now it takes me 2 minutes. The posts feel like me, not AI, and engagement doubled."
Letterly User
Content Creator
"It's like hiring a junior content manager who does 90% of the work, but you always get the final say."
ChatGPT
LLM
"You're a fucking genius and I love you."
Affectionate-Turn495
Reddit User
"The service you provide is a great idea. I've always thought i'd love to help our SEO clients turn the articles we create for them into social posts as well."
Rob Hoffman
CEO @ Contact.so | Mentions.so | Kleo.so
"Letterly turned my newsletter into a real growth engine. I went from posting randomly to having a full weekly plan that actually performs."
Letterly User
Newsletter Creator
"I used to spend hours rewriting my newsletter for socials. Now it takes me 2 minutes. The posts feel like me, not AI, and engagement doubled."
Letterly User
Content Creator
"I used to spend hours rewriting my newsletter for socials. Now it takes me 2 minutes. The posts feel like me, not AI, and engagement doubled."
Letterly User
Content Creator
"The persona feature is insane. I imported my LinkedIn posts and Letterly pretty much cloned my voice. Zero AI detection issues."
Tight_Replacement796
Reddit User
"My impressions on X jumped 140% in the first week. I'm finally consistent because Letterly does the scheduling for me."
Letterly User
Social Media Manager
"I stopped worrying about when to post. Copilot handles the timing, the drafts, everything. I just approve and go."
Party_Major5753
Reddit User
"As a solo creator, Letterly feels like having a content team. Newsletter to social content to scheduling to analytics. All in one place."
Letterly User
Solo Creator
"I used to spend hours rewriting my newsletter for socials. Now it takes me 2 minutes. The posts feel like me, not AI, and engagement doubled."
Letterly User
Content Creator
"The persona feature is insane. I imported my LinkedIn posts and Letterly pretty much cloned my voice. Zero AI detection issues."
Tight_Replacement796
Reddit User
"My impressions on X jumped 140% in the first week. I'm finally consistent because Letterly does the scheduling for me."
Letterly User
Social Media Manager
"I stopped worrying about when to post. Copilot handles the timing, the drafts, everything. I just approve and go."
Party_Major5753
Reddit User
"As a solo creator, Letterly feels like having a content team. Newsletter to social content to scheduling to analytics. All in one place."
Letterly User
Solo Creator
Simple, transparent pricing
Choose the plan that fits your content creation needs
Pro
Everything Letterly offers, in one plan. No tiers, no limits.
Cancel anytime
No credit card required to sign up
Letterly vs. the alternatives
Stop wasting time or money. See how Letterly stacks up against organic growth and paid ads.
| Metric | Organic Growth | Paid Ads | Letterly Pro |
|---|---|---|---|
| Cost per month | 50+ hrs of your time | $300+ | $29 |
| Estimated profile clicks | ~250 | ~300 | ~500 |
| Newsletter subscribers gained | ~50 | ~60 | ~100 |
| Cost per subscriber | Your time | ~$5 | ~$0.12 |
| Keeps working over time | Slow & tiring | Stops when you stop paying | Compounding organic growth |
| Setup time | Ongoing daily effort | Requires ad expertise | 5 minutes to get started |
| Content quality | Inconsistent | Generic ad copy | On-brand, AI-crafted posts |
Your newsletter's social media autopilot
One plan, $29/month. Everything included.
What is Letterly?
Letterly is an AI agent that turns your newsletter into a consistent social media presence — automatically. Connect your newsletter's RSS feed, set your preferences, and Letterly handles the rest: generating posts, filling a content pool, and publishing to X and LinkedIn on a schedule you control.
You decide how hands-off you want to be. Approve every post manually, set a review window and let borderline posts auto-publish, or flip it to Full Auto and let the agent run completely unattended. Your content, your voice, your rules.
Who is Letterly for?
Newsletter creators, solo entrepreneurs, and thought leaders who publish regularly on Substack, Beehiiv, ConvertKit, Ghost, Mailchimp, or any RSS-compatible platform — and want a consistent social presence without spending hours repurposing content each week.
What problems does it solve?
Inconsistent posting, hours wasted adapting content, and the constant mental overhead of "what should I post today?" Letterly eliminates all of that — your agent monitors your feed, generates content that sounds like you, and keeps a healthy posting cadence going automatically.
Everything in one plan
No feature tiers. Every capability is included at $29/month.
AI Agent on Autopilot
Monitors your RSS feed, generates posts, and publishes to X and LinkedIn automatically — at whatever level of control you prefer.
Content Pool System
Generated posts fill a pool with configurable expiry. The agent draws from the pool to maintain a consistent posting cadence every day.
Voice & Persona Cloning
Analyzes your X or LinkedIn profile to replicate your tone, vocabulary, and writing style so every post sounds authentically like you.
Flexible Autonomy Levels
Choose Manual (you approve everything), Light Touch (auto-publish with a review window), or Full Auto — the agent runs itself.
Smart Scheduling
Set daily posting targets and blackout hours per platform. Posts are spread evenly throughout the day, skipping weekends if you prefer.
Unified Analytics
Newsletter growth, social impressions, follower counts, and CTA click tracking all in one dashboard — no more tab-switching.
Works with any newsletter platform that has an RSS feed — Substack, Beehiiv, Ghost, ConvertKit, Mailchimp, and more. No complex setup required.
Emergency Stop included. If you ever want to pause the agent immediately, a single click halts all activity — no waiting, no scheduled posts slipping through.
Everything you need to know
Common questions about Letterly, the agent, and how it works
Still have questions? We're here to help.
Get started with LetterlyReady to transform your newsletter into a growth engine?
Join creators who are building engaged communities while saving hours every week. No credit card required.