Growth loop: make every customer bring the next one
A growth loop is the system where what your customers produce brings in the next ones. You learn to tell it apart from a funnel and from a one-off push, to name its four parts and to spot the type of loop that fits your business.
What it solves
If every month you have to push just as hard to get customers, this is where you find the wheel your business already has: what a happy customer leaves behind, and how that can bring in the next one.
To get started
In 2018, Brian Balfour, Casey Winters, Kevin Kwok and Andrew Chen published an essay at Reforge with a deliberately provocative title: Growth Loops are the New Funnels. They defined a loop as a closed system where inputs, through some process, generate an output that can be reinvested as new input.
Behind that definition sits one question, and you'll use it throughout this course:
How does one group of customers lead to the next group of customers?
That group is a cohort: the people who started with you in the same period, for example everyone who signed up in March.

An excerpt from the concept's reading. You study the rest with your tutor, applied to your business.
What you learn
- The month that starts from zero
- What a loop is
- The four parts
- Types of loops, with real cases
You study it in the course
Growth loops: grow your company faster
Sources
Every number in the concept comes from these sources. Examples and assumptions are labeled as such.
- Jim Collins, Turning the Flywheel (2019) y el concepto del flywheelReference book
- Nubank (Brasil), prospecto F-1 de Nu Holdings (1-nov-2021)Official or regulatory filing
- Nubank (Brasil; opera también en México y Colombia), prospecto de salida a bolsa (424B1 / F-1, 9-dic-2021)Official or regulatory filing
- Nubank, informe anual 20-F de 2025 (presentado el 8-abr-2026)Official or regulatory filing
- Nubank, resultados del 2T-2026Official or regulatory filing
- Bold (Colombia), programa de referidos de comercios (términos V.1.1.1, publicados el 13-nov-2025, vigentes desde el 28-nov-2025; el programa inició el 12-dic-2020)Industry source
- Brian Balfour, Casey Winters, Kevin Kwok y Andrew Chen, Growth Loops are the New Funnels (Reforge, 31-jul-2018)Industry source
- Brian Balfour, The Racecar Growth FrameworkIndustry source
- Dropbox, condiciones actuales del referidoIndustry source
- Dropbox, programa de referidos (charla de Drew Houston en Startup Lessons Learned, abril de 2010)Industry source
- Elena Verna, “B2B Product-Led Growth Non-Negotiable: TEAM Network Effects” (16-feb-2024)Industry source
- Hotmart (Brasil), sistema de afiliadosIndustry source
- Pinterest, loop de contenido por buscadores (Casey Winters)Industry source
- Platzi (Colombia), referidosIndustry source
- Rappi (Colombia), caso de BranchIndustry source
- Rappi, el arranque (entrevista de Y Combinator a sus cofundadores, 17-oct-2018)Industry source