EU-Hosted Feature Flags SaaS with 5 Published SDKs

A self-serve, B2B feature-flags SaaS: toggles, progressive rollout by percentage, targeting conditions, kill switches, and per-environment snapshots evaluated locally inside the SDK.

Stage: launched and running in production. A Go API on Cloud Run, a React console, an FR/EN marketing site and five client SDKs (JavaScript, Go, Python, PHP, .NET) are all deployed, and every SDK is published on its public registry — npm, PyPI, Packagist and NuGet. Infrastructure is fully described in Terraform, with Go unit and functional tests plus ~48 Playwright end-to-end scenarios. It runs unattended for about €25/month.

Revenue: pre-revenue. The free tier is open and the €49 / €99 plans are wired to Stripe, but the product shipped in August 2026 and was never marketed beyond SEO groundwork (6 indexed articles, sitemap, hreflang, JSON-LD, first-party analytics). No paying customers, so you are buying the build, not last month's income.

Niche: DevOps and infrastructure first — progressive delivery and release management for engineering teams — plus online developer tools. The commercial wedge is price and data residency: teams who find LaunchDarkly too expensive for toggles and rollouts, and European teams who want their flag data hosted in the EU (GCP europe-west1, no Google Analytics).

Handover includes the full source code, the domain, the GCP project transferred as-is, the Cloudflare zone, ownership of the four published SDK packages, the marketing site with its indexed articles, and the documentation (user guide FR/EN, admin API reference, architecture, deployment).

One thing I flag up front rather than let you find it later: the brand name is not a registered trademark, and an unrelated open-source library in the same field shares it.