The best open-source Marketing Ops tools, curated: 13 in the registry, including Apache Unomi, AtroCore, ResourceSpace. Every tool is open-source; each entry lists license, self-hostability, and links.
Usertour— tool, 2026-09-03 OSS alt to Userflow; ~2137 stars; via openalternative.co
Vikunja— tool, 2026-09-03 Lightest; Calendar+CalDAV for editorial
GeoLift— tool, 2026-08-25 Meta's geo-experiment framework (Synthetic Control Methods) for estimating the true incremental lift of ad campaigns when platform-reported conversions aren't enough.
Google Ads API Python Client— tool, 2026-08-25 Google's official Python client for the Google Ads API — build reporting, budget monitoring, anomaly detection, and controlled account-management (write-capable; gate mutations behind approval).
GrowthBook— tool, 2026-08-25 Open-source feature flags, A/B experimentation, and product analytics across 11 warehouse sources — prove whether an LLM-generated variation actually performs better.
Marketing Skills— tool, 2026-08-25 A collection of AI-agent skills for marketing tasks — CRO, copywriting, SEO, paid ads, analytics, launches, pricing, and lifecycle/growth marketing.
Meridian— tool, 2026-08-25 Google's media-mix-modeling (MMM) framework for measuring channel contribution and modeling budget allocation — privacy-safe marketing science, not ad-copy generation.
PyMC-Marketing— tool, 2026-08-25 Bayesian marketing toolbox in PyMC: media-mix modeling (MMM), customer lifetime value (CLV), and buy-till-you-die (BTYD) retention models.
Robyn (MMM)— tool, 2026-08-25 Meta's experimental marketing-mix-modeling package — models diminishing returns, response curves, and budget allocation across channels using ML.
TikTok Business API SDK— tool, 2026-08-25 TikTok's official SDK (Java/Python/JS) for its Business API — auth, campaign creation, reporting, and Business Center workflows. Apply the same test-account + approval rules to mutations.