About
Attrifast is a Stripe-native revenue attribution tool. It answers one question — which marketing channel actually drove this payment — without third-party cookies, without consent banners, and without the $200-$500/mo enterprise price tag.
For two years I ran growth and analytics for two bootstrapped SaaS products. Both used Stripe. Both used GA4. Neither could answer the simplest question a founder ever asks: which marketing channel actually drove this paid customer?
The technical reason is real. Safari blocked third-party cookies in March 2020. Firefox followed in June 2022. Chrome restricted them through 2024-2025. By 2026, roughly 50-65% of US web traffic and 60-75% of EU traffic moves through browsers that drop the very cookies GA4 needs for cross-session attribution. The $30 ad click on Monday and the $49 Stripe payment on Friday are no longer connected from inside any cookie-based tool. They show up as two unrelated events, and Stripe payouts stop matching Google Ads dashboards by 20-40% on cookie-blocking traffic.
I duct-taped a fix together with custom webhooks, a server-side UTM store, and a BigQuery join. It worked. It was also brittle, took two engineering days a quarter to maintain, and was embarrassing to demo to anyone outside the engineering team.
Attrifast is what that internal stack looks like when you spend nine months hardening it for somebody else's site. A 4kb first-party script captures UTMs into your own domain. A server-side webhook joins Stripe payment events to the original session. Revenue gets attributed to the channel that actually earned it — even when the user came back six days later on a different device.
This is a one-person company. I write the product, the docs, the blog, and the SQL on customer support. There is no marketing team and no AI ghostwriter pumping out 50 SEO articles a month. Every blog post on this site is something I have personally tested against my own data, my customers' data, or a real internal measurement — never a reheated summary of someone else's post.
When I quote a number — "Stripe payouts diverge from Google Ads dashboards by 20-40% on cookie-blocking traffic", "Safari + Firefox = 50-65% of US desktop traffic", "the average return-visit delay penalty is 0.55 at 6 days" — it comes either from a primary source I link to inline or from measurements I ran on real properties. If I do not have a source or a measurement, the number does not get into the post.
If you ever find a wrong number on this site, email me at vincent@sproutfi.xyz and I will fix it within 24 hours, with a public correction note on the article. That is the editorial policy.
Attrifast does not load any third-party scripts. It does not use cookies that survive a session reload, does not fingerprint visitors, and does not share data with ad networks. It captures UTM parameters into a first-party identifier scoped to your domain, then joins that identifier to Stripe payment events on the server. The full data inventory is in the privacy policy.
I think of revenue attribution as a small problem with a large shadow: getting it right unlocks honest budget decisions, and getting it wrong (or paying $300/mo for a tool to get it mediocre) is the default state for most bootstrapped founders. Attrifast is opinionated about that default being fixable.
Email vincent@sproutfi.xyz. I read everything personally. If you are evaluating Attrifast for a specific Stripe stack and want me to look at your dashboard, I am happy to do that on a 20-minute call — just include "Attrifast eval" in the subject line.
Connect on LinkedIn — that is where I post when I have shipped something interesting.