SmartLead founder Vaibhav Namburi shares how 11 failed businesses, WhatsApp community presence, and platform-as-a-service thinking built an email infrastructure managing 5-7 million mailboxes and 110M+ daily warmup emails.
Vaibhav Namburi, founder of SmartLead, failed at 11 businesses over seven years before building one of the largest email infrastructure platforms in B2B. A mechanical engineer who failed his programming classes, he taught himself to code and now manages 5-7 million mailboxes sending over 110 million warmup emails daily.
Listen to this episode to learn why customer support beats Facebook ads for agency acquisition, how observing user behavior in WhatsApp groups drives product decisions that move deliverability metrics, and why treating your platform as infrastructure rather than traditional SaaS changes everything about customer relationships.
Vaibhav Namburi built SmartLead into one of the largest email infrastructure platforms serving agencies and SaaS companies worldwide. The platform processes 5-7 million mailboxes, sends 80-120 million warmup emails daily, and handles 7-32 million actual campaign emails per day.
Before SmartLead, Vaibhav ran a development agency for seven years while launching 11 failed products, including recruitment platforms, remote work tools, finance products, and e-commerce ventures. He was OpenAI user #900, building SmartRider (an early Clay-like orchestration tool) before pivoting to email infrastructure when customers repeatedly asked for a better sequencing solution.
[00:30] How SmartLead evolved from agency tool to enterprise platform serving companies doing hundreds of millions in ARR
[01:05] The upmarket shift: How agencies introduced SmartLead to enterprise clients with complex compliance requirements
[03:52] The status quo challenge: How Vaibhav builds features by observing user behavior patterns instead of waiting for requests
[06:32] WhatsApp as growth engine: Why dark social presence drives product decisions and business growth
[08:31] The platform-as-a-service mindset: Why SmartLead operates like AWS, not Amazon.com
[13:19] The anti-pattern founder: Mechanical engineering, failed programming classes, and learning to code for survival
[18:26] From football dreams to SaaS: International representation, music, and the winding path to entrepreneurship
[20:24] OpenAI user #900: How early GPT-3 API access led to SmartRider and eventually SmartLead
[22:38] The 11 failures: Seven years of products that didn't work and the lessons that made SmartLead possible
[24:12] Scale revealed: 5-7 million mailboxes, 110 million warmup emails daily, and billions of monthly API pings
[26:35] Full circle: From building OpenAI wrappers to becoming the platform others build wrappers on
"There's no amount of Facebook ads you can throw to get an agency to convert, in my opinion," Vaibhav explains. SmartLead's growth strategy centers on presence in customer communities rather than traditional marketing. This stems from recognizing they operate as platform-as-a-service rather than traditional SaaS.
"I can't operate as Amazon.com, which is here's where your order is. I need to operate as Amazon web services, which is something that breaks. I need to be there," Vaibhav notes. This philosophy extends beyond founder involvement to the entire team. For SaaS leaders selling to agencies and technical buyers, support-first culture drives retention and word-of-mouth growth more effectively than paid acquisition.
Rather than implementing requested features, the SmartLead team identifies patterns and builds solutions proactively. "The platform was built by the users and not by us, is generally just speaking to more and more people and not even asking questions, but just observing weird behaviors that each person's performing," Vaibhav explains.
When users created automations to pause campaigns on bounces, the team built bounce thresholds directly into the product. "Was there data behind that? Did anyone ask for it? No, it was just that when we speak to a bunch of people and we keep seeing that this is a repeated behavior and pattern, we're like, that sounds silly, we can just do that for you." This observation-based methodology produces features that solve actual workflow friction rather than perceived needs.
Vaibhav identifies a direct correlation between community presence and growth periods. "Whenever I look at low periods within the business, those are the times where I was not active on WhatsApp," he reveals. Even at a massive scale, he maintains direct presence in customer WhatsApp groups, responding to tags and participating in daily conversations.
This engagement provides real-time feedback loops informing immediate product decisions. The upcoming Outlook deliverability improvement came directly from a customer observation shared in these communities. As we discuss in the episode, SaaS leaders should consider how to maintain these feedback mechanisms as they scale, whether through founder involvement or systematic customer connection protocols.
"Every tool holds almost similar comparability. You can look at a 5% float up and down, which again, if you average that over like a six month window, it's actually all nullified to the same point," Vaibhav observes. In mature SaaS categories, technical capabilities converge, making pricing, convenience, and team relationships the deciding factors.
"Founders or businesses end up just deciding who to work with based upon pricing, convenience, and if they like the team, like the support side of things." This shifts competitive advantage from feature differentiation to customer experience. For SaaS companies in commoditizing markets, engineering resources matter less than being present for customers and building genuine community relationships.
Vaibhav's 11 failed businesses over seven years created the foundation for SmartLead. "Those nine, eight, nine years, whatever it was, was necessary because I feel like if I didn't get that preparation, I wouldn't have the right framework," he reflects. Failed attempts included recruitment platforms, remote work tools, finance products, developer tools, and multiple e-commerce ventures.
The experience taught perspective on customer complaints. "For me, it's a privilege when a customer complains. The disheartened meant I would feel when I would discover that bug saying that, that means basically no one used the application." Previous products had bugs nobody complained about because nobody used them. This reframe helps SaaS leaders view customer friction as engagement signals rather than purely negative feedback.
SmartLead's transformation happened through an unexpected API request. "Chris Fry reached out three years ago saying, hey, do you have an API that I can automate with? We didn't have an API. No one was asking for an API," Vaibhav recalls. Building the API despite lack of demand created the foundation for their platform-as-a-service model, now handling billions of monthly API pings.
At Understory, we see this pattern repeatedly: the tools that become foundational infrastructure for coordinated campaigns are those built API-first. Customers become development partners, building integrations that make switching costs prohibitive. SaaS leaders should consider how API access could transform their products from tools into platforms, even when customers aren't explicitly requesting programmatic access.
SmartLead's path to enterprise came through agency relationships. "We had some fun agencies and freelancer businesses who work with really large firms and they got to know about us a little sooner than usual," Vaibhav explains. Large enterprises hesitated to adopt directly due to compliance concerns, but agencies working with Fortune 500 companies became the natural bridge.
"Usually they wouldn't work with us directly because they're afraid to put their credit card inside there, they're not too sure what it is, software compliance blah blah,” These are issues that agencies solve by handling trust concerns. For technical SaaS tools, focusing on service providers who work with enterprise clients creates an indirect but effective path to larger deals without building expensive enterprise sales teams.
Managing 5-7 million mailboxes means defending against constant attacks. "We have people try to bring our system down almost every other day. People trying to come in and scrape our warm-up pool, come in and try and sabotage the warm-up pool," Vaibhav reveals. At SmartLead's scale, the warmup network becomes a prime target for manipulation.
The team built machine learning models to identify bad actors creating mass accounts to disrupt service. "We figured out a way where they think they know, but they think they don't know," Vaibhav explains. SaaS leaders building critical infrastructure should plan for adversarial usage from day one, not after achieving scale.
Want more insight on building email infrastructure and SaaS platforms? Listen to the full episode on YouTube and subscribe to Understory's podcast for more founder stories and growth tactics.
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