About
Nikita Balanov is the founder of TechStackReviews and has spent 14+ years in B2B sales. Most recently at Deel (YC W19) where he earned the GOAT23 award, with prior roles at FullEnrich and Brite Payments — building AI-native GTM systems for B2B scaleups across outbound, RevOps and workflow automation. He started TechStackReviews because most "best of" lists for sales tools are written by people who have never run a sequence — these reviews come from someone who has actually used these tools to hit quota.
Areas of expertise
Reviews
Apollo.io Review
Apollo.io is the most popular all-in-one sales engagement platform on the market — combining a 275M+ contact B2B database, multichannel sequencer, dialer and an AI assistant in a single workspace. For most founders, SDR teams and agencies it offers the strongest price-to-power ratio of any cold email software, and replaces the classic ZoomInfo + Outreach + Lemlist stack. This Apollo.io review breaks down where it shines, where it falls short, and the alternatives worth considering.
Lemlist Review
Lemlist is one of the most polished AI sales engagement platforms for SMB and scale-up teams that want true multichannel outbound — email, LinkedIn, WhatsApp and calls — in a single sequencer. Beyond the multichannel core, it ships AI agents that detect buying signals, a 600M+ B2B lead database, the Lemwarm email warmup booster and an AI personalisation engine. This Lemlist review covers what it does best, where it stops being the right pick, and the strongest Lemlist alternatives on the market.
Instantly.ai Review
Instantly.ai is the most popular cold email software for agencies and high-volume outbound teams in 2026. It bundles unlimited sending inboxes, an AI-driven email warmup network of 1M+ accounts and inbox rotation that keeps deliverability high even at agency scale. This Instantly.ai review covers exactly when it's the right pick, where it falls short, and the best Instantly.ai alternatives.
Smartlead Review
Smartlead is the favourite cold email software for technical lead-gen agencies that want true unlimited mailboxes, granular control of inbox rotation and a powerful API. Together with the AI warmup network and master inbox, it's the closest direct competitor to Instantly.ai. This Smartlead review covers strengths, weaknesses, pricing and the best Smartlead alternatives.
HeyReach Review
HeyReach is the best LinkedIn automation tool for agencies and SDR teams that need to run LinkedIn campaigns across many sender accounts from a single dashboard. Where most LinkedIn tools are built for one user, HeyReach is built for multi-account outbound at scale — and that's why it's become the default LinkedIn layer for serious agencies. This HeyReach review covers strengths, weaknesses, pricing and the best HeyReach alternatives.
Reply.io Review
Reply.io is one of the most mature AI SDR + multichannel sales engagement platforms on the market. Its AI SDR Jason can autonomously research prospects, write personalised messages and book meetings, while the underlying sequencer handles email, LinkedIn and calls. This Reply.io review covers where Jason actually delivers, where Reply.io still trails its competitors, and the best Reply.io alternatives.
Best-of guides
Alternatives guides
Comparisons
Editorial independence. All reviews are written independently. Some links on this site are affiliate links — we may earn a commission at no extra cost to you. Commission size never influences rankings or recommendations. Read the full affiliate disclosure.