If you’re in sales, you already know the grind. Sending connection requests one by one. Copy-pasting follow-up messages. Trying to remember who replied, who ghosted, and who said “maybe next month.” And by the time you’ve done all of that manual work, the week is over and your calendar is still half-empty.
That’s the exact problem Sbl.so was built to solve — and it does it remarkably well.
In this review, we’re going to take a deep dive into what Sbl.so actually is, who it’s best for, what makes it stand out from every other LinkedIn automation tool on the market, and whether the AppSumo lifetime deal is worth jumping on. Spoiler: it probably is.
What Is Sbl.so?
Sbl.so (short for Second Brain Labs) is an AI-powered LinkedIn outreach and sales automation platform. It doesn’t just automate the boring stuff — it handles the intelligent stuff too. We’re talking about AI that reads replies, handles objections, qualifies prospects, and books sales calls directly onto your calendar. All on autopilot.
The brains behind this tool are Shubham Kumar and Ayush Singh, two co-founders out of Karnataka, India, who got frustrated watching sales teams burn hours on repetitive outreach that wasn’t converting. Their insight was simple but powerful: existing tools were built around bulk messaging, not genuine conversation. So they built something different — a platform trained on over a million real sales conversations, powered by what they call a Persuasion Chat Model.
The result? A tool that doesn’t just send messages. It talks to your leads.
Who Is Sbl.so Built For?
This tool is a perfect fit for:
Solopreneurs and freelancers who need a steady stream of leads but don’t have time to manually work LinkedIn every single day. Sbl.so essentially gives you the output of a full-time sales development rep without the $60,000/year salary.
Sales managers and sales teams who want to scale outreach across multiple LinkedIn profiles without managing a maze of spreadsheets and CRMs. The unified inbox and multi-account support make it incredibly manageable.
Marketing agencies running lead gen campaigns for multiple clients. The multi-workspace support (especially at higher tiers) makes it easy to keep campaigns clean, organized, and separated by client.
If you’re a founder who wears too many hats, a B2B consultant trying to fill a pipeline, or a sales team lead looking to increase meetings without increasing headcount — Sbl.so was made for you.
Core Features That Actually Matter
1. AI-Powered Lead Generation with ICP Prompting
One of the coolest things about Sbl.so is how it handles lead sourcing. You don’t go hunting for prospects manually. Instead, you simply describe your ideal customer profile (ICP) — something like “SaaS founders in the US with 10-50 employees who are actively hiring sales reps” — and the platform pulls a targeted lead list automatically.
It even layers in intent signals. For example, it can trigger outreach when someone likes or comments on a competitor’s post, or when a company posts a hiring signal like “We’re looking for a Head of Sales.” These aren’t cold leads you’re interrupting — these are warm prospects who are already thinking about the problem you solve. That’s a game-changer for reply rates.
Higher tiers also unlock Curated Leads, which pulls from multiple premium data sources for niche ICPs where data quality really matters. Tier 1 users get 4,000 curated leads, Tier 2 gets 10,000, and Tier 3 gets 15,000 — all lifetime credits.
2. Fully Automated Outreach That Sounds Human
This is where Sbl.so separates itself from tools like Waalaxy, Expandi, or HeyReach. Those platforms are essentially message schedulers — they send your pre-written sequence and hope someone responds. Sbl.so goes further.
Once a prospect accepts your connection request, the AI takes over. It sends a personalized opener, monitors engagement, and if someone replies — even with an objection — the AI reads the reply and responds intelligently. It can answer questions about your product, handle pushback, qualify the lead further, and ultimately move the conversation toward booking a call.
You can also drop in rich media at scale — AI-cloned voice notes, videos, PDFs, images, or links — to make your outreach feel personal and high-touch even when it’s running completely automatically.
And if a lead gets really hot, you can manually intervene without losing campaign momentum. The system is smart enough to pause automation when you step in and resume when you’re done.
3. Smart Follow-Up Sequences
Follow-ups are where most salespeople drop the ball — not because they don’t want to follow up, but because life gets busy. Sbl.so handles this with sequenced follow-ups and custom delays. The system monitors replies, engagement levels, and inactivity, and adjusts accordingly.
Didn’t reply in three days? It sends a gentle nudge. Opened the message but didn’t respond? Different message. Replied but went cold? Another touchpoint. The AI keeps the conversation alive so you don’t have to.
4. Calendar Booking on Autopilot
Here’s the part that makes this tool genuinely special: Sbl.so doesn’t just warm up leads — it books calls directly onto your calendar. Once the AI has qualified a prospect and they’ve expressed interest, it handles the scheduling. You literally just show up to the call ready to close.
This is what the founders mean when they say “fill your calendar with AI-booked sales calls.” It’s not a marketing tagline. It actually does this.
5. Multi-Account Scaling With LinkedIn Safety Built In
One of the biggest concerns with LinkedIn automation is getting your account flagged or banned. Sbl.so takes this seriously. The platform runs safe, platform-compliant sequences that automatically respect LinkedIn’s daily and weekly limits.
Better yet, you can add unlimited sender accounts into one workspace, and the system auto-rotates between them the moment one hits its limit. This means you can scale outreach to hundreds or even thousands of new prospects per month without ever putting a single account at risk. Each sender profile can reach up to 800 new prospects per month, and with multiple accounts, that number compounds fast.
6. MCP Server Integration — Truly Next-Level Stuff
In a move that sets Sbl.so apart from practically every other sales tool out there, they’ve launched an MCP (Model Context Protocol) server. This means you can connect Sbl.so directly into Claude, ChatGPT, Gemini, or any AI assistant that supports MCP.
What does that mean in practice? You can manage campaigns, check your reply queues, and run your entire outreach operation from inside your AI workspace — without ever opening another tab. You could literally type “Build me a campaign for SaaS founders in the US, book a demo call” into Claude and it just does it.
For AppSumo lifetime users, MCP access is completely free with unlimited usage.
7. Content Engine (New!)
On top of outreach, Sbl.so recently launched a Content Engine — a self-improving content system that generates LinkedIn posts in your exact voice. You give it a content pillar (like “AI in B2B sales”), it scrapes the web for trending angles, drafts 20+ post ideas, and writes full posts that sound like you — not a robot.
It learns from your edits using reinforcement learning, so the more you use it, the better it gets. You can even schedule directly from inside the tool.
Tier 1 users get 1 pillar/month, Tier 2 gets 3, and Tier 3 gets 6. A nice bonus on top of already-strong outreach capabilities.
The AppSumo Deal: Is It Worth It?
Let’s talk numbers, because the AppSumo pricing here is genuinely exceptional.
Tier 1 — $89 (one-time) 10,000 outreach credits, 1 active LinkedIn account, basic campaign performance metrics, ICP leads, unified inbox, campaign sequence builder, AI training on your product and tone, A/B testing, simulate AI replies, and full Sbl App access.
Tier 2 — $249 (one-time) 30,000 outreach credits, 40 active LinkedIn accounts, advanced metrics, 2 workspaces, lead scoring, Sales Navigator integration, and intent signals. This is the recommended tier for agencies or anyone running campaigns for multiple clients.
Tier 3 — $599 (one-time) 75,000 outreach credits, 80 active LinkedIn accounts, advanced metrics, 4 workspaces, and everything else.
Compare this to paying $99–$199/month for tools like Expandi or Waalaxy — the Sbl.so lifetime deal pays for itself within a few months at most. And if you need more credits down the road, top-ups are available at just $60 per 10,000 credits ($0.006 per prospect reached). The first 100 AppSumo buyers even get a special rate of $20 per 10,000 credits as a thank-you.
All plans come with lifetime access, all future plan updates, and a 60-day money-back guarantee through AppSumo. That’s two full months to run campaigns and decide if it’s working for you — with zero risk.
What Real Users Are Saying
Sbl.so currently holds a 4.82 out of 5 star rating on AppSumo based on 38 reviews — which is remarkably high for a sales automation tool that often comes with steep learning curves. The AI-summarized feedback from AppSumo highlights three areas of consistent praise: exceptional AI conversation handling, effortless lead sourcing, and the unified inbox for multi-account management.
Minor critiques include a slight learning curve when getting started, and occasional UI glitches — which is pretty expected for a startup-stage product that’s actively shipping updates. The founders are clearly listening to community feedback; recent updates including curated leads, MCP integration, intent signals, and the content engine all came directly from user requests.
What Makes Sbl.so Different From the Competition?
Let’s be honest — there are a lot of LinkedIn automation tools out there. Here’s why Sbl.so stands out:
Most tools are just message schedulers. They send your pre-written scripts and leave the real work to you. Sbl.so is different because the AI is doing the actual selling — reading replies, handling objections, qualifying prospects, and booking calls. It’s not just automation; it’s an AI sales rep.
The intent signal feature is genuinely rare. Most tools can’t tell you when a prospect just interacted with your competitor or posted a hiring signal. Sbl.so can, and it lets you time your outreach for maximum relevance.
The MCP server integration is ahead of its time. As AI assistants become a bigger part of how people work, being able to control your outreach pipeline from inside Claude or ChatGPT is a massive productivity unlock.
And the active, responsive founding team makes a real difference. Shubham and Ayush are in the AppSumo community, responding to questions, shipping updates, and treating their early customers like partners. That energy matters for a tool you’re depending on to grow your business.
Minor Things to Keep in Mind
No product is perfect, and Sbl.so is no exception. A few things worth knowing:
Credits are consumed when you send a new LinkedIn connection request — everything after that (follow-ups, AI replies, objection handling, call booking) is free. So you’ll want to keep an eye on your credit balance and top up as needed.
The platform is best suited for LinkedIn outreach specifically. WhatsApp outreach is listed as coming soon in some documentation. If you need deep CRM integrations or email outreach as a core feature right now, this may not be your all-in-one solution yet — though the team is clearly building fast.
There’s also a learning curve when setting up your first campaign and training the AI on your product and tone. Budget an hour or two for initial setup, and you’ll be rewarded with a pipeline that basically runs itself.
Final Verdict: Should You Buy Sbl.so?
If you do any B2B sales on LinkedIn — and most professionals do — Sbl.so is one of the most compelling tools on the market right now. The combination of automated lead sourcing, AI-driven conversations, intent signals, calendar booking, and multi-account scaling in a single platform is genuinely rare.
At $89 for lifetime access on Tier 1, this is a no-brainer for solopreneurs and consultants. At $249 for Tier 2, it’s one of the best investments a sales team or agency can make. The 60-day money-back guarantee means there’s essentially zero risk in trying it.
If you’ve been spending hours a week on manual LinkedIn outreach and still not filling your calendar the way you want to — Sbl.so might just be the tool that changes that.
Rating: 4.8/5 ⭐
Available now on AppSumo with lifetime pricing. Deal terms require new users only, and licenses must be activated within 60 days of purchase.
