Abby is an open-source, TypeScript feature management and A/B testing platform that pairs statically typed SDKs for core JavaScript, React, Next.js, Angular and Svelte with a dashboard the non-developers on a team can use, aimed at developers who want feature flags and remote config without sending user data to a third party.

What it is

Abby is an open-source feature management and A/B testing platform written entirely in TypeScript. It provides a statically typed API for feature management and experimentation, backed by official SDKs for core JavaScript, React, Next.js, Angular and Svelte, all sharing one core package. Alongside those SDKs it offers a dashboard that the non-developers on a team can operate, so flags and experiments do not require an engineering ticket. The codebase is a Turborepo managed with pnpm, containing a documentation site built with Next.js and Nextra and a web application built on the T3 Stack with tRPC and Tailwind CSS.

The concrete problem it solves is the ordinary one that pushes teams toward a hosted feature-flag vendor: gating features, running A/B tests and changing remote configuration without redeploying. Hosted services of that kind mean shipping user data to a third party and accepting a subscription or usage-based cost. Abby replaces that arrangement with something self-hostable and privacy-focused — it does not track personalized user data and uses no marketing cookies — while keeping the developer experience typed, so flag reads are checked rather than guessed at.

Key capabilities

• Statically typed API for feature management and A/B testing, so flag definitions carry types through to the read site.
• Five official SDKs over one shared core: core, react, next, angular and svelte.
• Dashboard designed for non-developers to manage flags, remote config and experiments.
• Privacy-first operation: no personalized user data tracked and no marketing cookies used.
• Two deployment paths, self-hosted or the hosted version at tryabby.com.
• Turborepo monorepo layout with a web app on the T3 Stack (tRPC, Tailwind CSS) and a docs app on Next.js with Nextra.
• Local development mail interception through a MailHog instance declared in docker-compose.yml at localhost:8025, which catches the one-time verification link.

Who uses it and how

• Product teams where non-engineers need to toggle flags and adjust remote configuration without developer involvement.
• Next.js and T3 Stack projects, which get a dedicated next SDK and match the stack the web application itself is built on.
• Teams on other frontend frameworks, covered by the Angular and Svelte SDKs sharing the same core.
• Privacy-conscious organisations that cannot send user data to third-party flag vendors and prefer to run the platform themselves.
• Self-hosters who clone the monorepo and run the whole stack on their own infrastructure, supplying their own database and mail setup.

Getting started

Clone [email protected]:tryabby/abby.git, then run pnpm i, pnpm build:packages, pnpm db:start, copy apps/web/.env.example to apps/web/.env, run pnpm db:migrate and start with pnpm dev. A hosted version is also available at tryabby.com.

How it compares

No list of paid products and no similar tools are named in the facts provided, so Abby stands alone in this registry; nothing here is documented as a direct equivalent.

When to use it — and when not to

Self-hosting means operating a database, since the setup runs pnpm db:start and pnpm db:migrate, and an email path for account verification, where the bundled docker-compose.yml supplies MailHog at localhost:8025 — a development convenience rather than production mail. The licence is AGPL-3.0, a strong copyleft that will not suit teams embedding the code in proprietary products without meeting its terms. Teams that need vendor-managed hosting, SLAs or commercial support should choose a paid service instead, and the project currently carries 31 open issues, so expect an active but not fully settled codebase.

git clone [email protected]:tryabby/abby.git
pnpm i
pnpm build:packages
pnpm db:start
cp apps/web/.env.example apps/web/.env
pnpm db:migrate
pnpm dev