Show IH: I built a BuiltWith alternative solo in 90 days – 46M sites indexed, first paying customer
Hey IH,
I'm Sergey — solo founder. I've been building TechSpy for the last 90 days, and it just got its first paying customers. Sharing here because this community is where I've been learning how to build in public.
What it does
TechSpy lets you find companies by the technology they use. Type "Shopify" and get a list of Shopify stores. Combine "Klaviyo + NOT Attentive" and get every email-marketing brand that hasn't added SMS yet. Export to CSV for your SDR team.
BuiltWith does this — for $295/mo. Wappalyzer does a subset — but no multi-filter, no export on free. TechSpy starts at $49/mo, with a generous free tier (50 searches/day, no card).
The numbers
- 46M domains in the index (CommonCrawl + Majestic + Tranco)
- 557K+ active sites with detected technology data
- 1,319 unique technologies detected
- Re-crawls active sites weekly
- 6 HTTP crawlers + 2 Playwright (headless browser) workers across 2 servers
What I built it with
FastAPI, PostgreSQL, asyncpg, Playwright. My co-engineer: Claude. Genuinely — I'm not a backend dev by background, and I couldn't have shipped this without AI pair programming. The infra is more complex than anything I've built before.
What's working
The data is good. I published two free research reports from our own index — tech stack breakdowns of the top 50 US furniture brands and 55 DTC health & wellness brands. Both got decent organic pickup.
People searching for "BuiltWith alternative" land on our /vs/builtwith page and convert at a reasonable rate.
What's hard
Distribution. Zero followers on Twitter. HN and IH posts drafted but never shipped (until today). The product is ready — the gap is getting in front of the right people: SDRs, ecom agencies, growth teams who do competitor research.
Try it
techspy.pro — free to search, no card required.
Happy to answer anything about the build, the data, or the business. If you work in sales or ecommerce and this is useful, I'd love to know what's missing.
This is a stronger product than most “BuiltWith alternative” attempts because you already have two useful wedges: cheaper stack intelligence and actual prospecting use cases.
I’d be careful not to position TechSpy only as “BuiltWith but cheaper” though. That gets attention from comparison traffic, but the higher-intent buyer is probably not looking for a database. They’re looking for account lists they can act on immediately.
The Klaviyo + NOT Attentive example is the strongest part of the post because it shows a real outbound use case:
find ecommerce brands with one tool installed, missing another, then pitch the gap.
That is much sharper than generic tech lookup.
For distribution, I’d probably build around 2 or 3 repeatable prospecting plays rather than broad awareness:
ecom agencies finding brands missing retention tools
SDRs finding accounts with competitor/complementary stacks
growth teams doing market/account research before outreach
The real test is not “can TechSpy get traffic?” It is whether one of those groups sees a filtered list and immediately thinks: “I can use this to sell this week.”
Happy to put a tighter version in writing if useful. I’d map the best first buyer segment, the strongest outbound angle, and a simple 7-day plan to turn TechSpy from a search tool into a prospecting workflow.