@reventlessdev/rescript-moment

Reventless Core

Alpha release. Reventless is under active development on the alpha branch. APIs, package layouts, and on-disk formats can change without notice, and releases may include breaking changes between versions. Pin exact versions and expect churn.

Known issue — apps can't be created or run from the published packages yet. Package publishing to the registry is currently broken, so the @reventlessdev/* packages needed to scaffold and run a Reventless application aren't installable. This is being worked on and should be resolved soon. In the meantime you can still build and run the bundled hybrid example from source in this repo.

Reventless is a spec-driven, event-sourced CQRS platform for serverless applications. You describe your domain as commands, events, and projections in type-safe ReScript; the framework provisions and wires the infrastructure — queues, tables, functions, event routing, serialization, and the GraphQL and MCP APIs — with Pulumi.

Full documentation: docs.reventless.dev.

It is a holistic approach for building event-based business applications, consisting of:

• A Methodology (Event Storming–based) which covers the full delivery cycle
• A Programming Model which focuses on business value
• A Domain Independent reusable Framework to optimize operational costs

It enables developers to focus on business value and ship fast by providing a hierarchical component model that guides towards best-practice architectural patterns, with everything evolving around commands & events that are part of a ubiquitous language shared across all stakeholders.

Core Technologies & Patterns

Reventless leverages modern architectural patterns and technologies:

• Domain-Driven Design (DDD) - Aligns software design with business domains and ubiquitous language
• Event-Driven Architecture - Asynchronous message-based communication between components
• Event Sourcing - Stores application state as a sequence of events (source of truth)
• CQRS - Separates read and write operations for optimized performance and scalability
• ReScript - Type-safe functional programming language compiling to JavaScript, see here
• AWS Serverless - Cloud-native deployment using Lambda, DynamoDB, SQS, SNS, and more
• Infrastructure as Code (IaC) - Automated infrastructure provisioning and management using Pulumi
• Hierarchical Component Model - Modular, reusable architectural components with built-in infrastructure definitions (via Pulumi)

Packages

This is a pnpm + Lerna monorepo. Packages are grouped by type into four workspace folders:

Folder	Purpose
reventless/	Reventless framework + extension packages
rescript/	ReScript bindings for JS/npm libraries
examples/	Example applications
packages/	Build tooling and documentation only

Framework (reventless/)

• reventless-spec — type specifications and interfaces
• reventless-core — core framework (provider-agnostic)
• reventless-aws — AWS adapters (DynamoDB, Lambda, SQS, SNS, S3)
• reventless-local — local platform for local dev and testing
• reventless-infra, reventless-interop, reventless-gwt

ReScript bindings (rescript/)

rescript-aws-sdk, rescript-pulumi-aws, rescript-pulumi-pulumi, rescript-uuid, rescript-fast-csv, rescript-hash-object, rescript-node-streams, rescript-node-zlib, rescript-ssh2, rescript-graphql-yoga, rescript-moment (shared with the UI repo).

Examples (examples/)

• online-shop-hybrid — the canonical end-to-end example (aggregates and DCB slices); runs locally in-memory and deploys to AWS
• online-shop-aggregates, online-shop-dcb — single-style variants

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Getting Started

Prerequisites

• Node.js v22.17.1 — see .node-version. fnm / nvm will pick it up automatically.
• pnpm 10 — this repo enforces pnpm via packageManager + corepack. Enable with corepack enable. Do not use npm.
• Git.
• OCaml toolchain (opam + dune) — only if there is no prebuilt ReScript PPX binary for your platform (see PPX binary below). Prebuilt binaries cover Linux x64 and macOS arm64; other platforms build the PPX from source during setup.

Quick start (clone → running example)

git clone <repo-url> reventless-core
cd reventless-core
corepack enable          # ensures the pinned pnpm version

pnpm run setup           # one-command bootstrap (see below)

# Run the hybrid example backend (GraphQL + MCP; SQLite stores by default,
# or `pnpm run serve:memory` for in-memory):
cd examples/online-shop-hybrid/platform-local
pnpm run serve

Then log in to the Domain GraphQL server as admin / admin:

curl -s -X POST http://localhost:4000/__inmemory/login \
  -H 'content-type: application/json' \
  -d '{"username":"admin","password":"admin"}'

Endpoints once serve is running:

Service	URL
Domain GraphQL (+ /__inmemory/login, /sdl)	http://localhost:4000/graphql
Platform GraphQL (+ graphql-ws subscriptions)	http://localhost:4001/graphql
Domain MCP	http://localhost:3001/mcp
Platform MCP	http://localhost:3002/mcp

See examples/online-shop-hybrid/README.md for the full example (including the host-shell UI via pnpm run dev:full) and AWS deployment.

What pnpm run setup does

scripts/setup.mjs is idempotent and runs, in order:

1. Creates pnpm-workspace.yaml — it is gitignored (a symlink to pnpm-workspace.base.yaml, so the cross-repo dev overlay used by pnpm link:on / link:off can swap it). A fresh clone has none, so plain pnpm install would fail with ERR_PNPM_WORKSPACE_PKG_NOT_FOUND. (Manual equivalent: node scripts/workspace-setup.mjs.)
2. pnpm install — from the repo root.
3. Ensures the ReScript PPX binary for your platform (prebuilt, or built from source — see below).
4. Seeds examples/.../platform-local/.reventless/users.yaml from the committed users.example.yaml so local login works (admin/admin, user/user).
5. Builds the hybrid in-memory example (skip with pnpm run setup --no-build).

To build everything instead of just the example: pnpm run build. To run the full test suite: pnpm test.

PPX binary

Reventless uses a native ReScript PPX (@reventlessdev/reventless-ppx). Prebuilt per-platform binaries exist for Linux x64, macOS arm64, and macOS x64 — but they live on a private GitHub Packages registry, so installing them needs a GitHub token with read:packages (set GITHUB_TOKEN in your environment; see .npmrc).

Without a token, or on a platform with no prebuilt (e.g. Linux arm64), pnpm run setup automatically builds the PPX from source via opam exec -- dune build — this is the zero-config path and just needs the OCaml toolchain installed. Manual build:

(cd packages/reventless-ppx/src && opam exec -- dune build)
cp packages/reventless-ppx/src/_build/default/bin/bin.exe \
   packages/reventless-ppx/ppx-osx-x64.exe   # name depends on platform; see packages/reventless-ppx/bin

Windows: build and run inside WSL2 (it presents as Linux x64); there is no native Windows binary.

For detailed development workflow and contributing guidelines, see CONTRIBUTING.md.

Documentation

Full documentation is published at docs.reventless.dev.

It is a Docusaurus site under packages/doc/ — to run it locally:

pnpm --filter ./packages/doc run start   # dev server with hot reload

See CLAUDE.md for build commands and an architecture overview.

Related Repositories

• reventless-ui — a companion React component/UI library for Reventless applications, distributed separately. It consumes rescript-moment from this repo.

Architecture

Reventless is an event-sourced CQRS framework designed for serverless infrastructure, written in ReScript.

Package Hierarchy

reventless-spec (foundation)
  ↓
reventless (core framework + all bindings)
  ↓
reventless-aws (AWS adapters)

Key Components

• Aggregate - Event-sourced aggregate root with CommandTopic, EventLog, CommandGenerator
• ReadModel - Query-side projection consuming events via EventCollector
• Plugin - Deployable unit containing aggregates, read models, extension points
• Core - Application core orchestrating all components

Adapter Pattern

The framework separates deploy-time (Pulumi infrastructure) from runtime (Lambda handlers):

• src/adapter/ - Deploy-time adapter interfaces
• src/adapter/Runtime/ - Runtime builders (Single, PerAggregate, Micro)

AWS adapters implement:

• EventLog storage → DynamoDB
• CommandTopic/EventTopic channels → SQS (FIFO), SNS
• QueryDb → DynamoDB
• Task buckets → S3

License

Reventless is licensed under the Apache License 2.0.

Provenance

Reventless was originally developed (2019–2025) by Atos Austria GmbH / Eviden Austria GmbH and used in production before its open-source release. The intellectual-property rights were subsequently transferred to Martin Lorenz, who released it under the Apache License 2.0 in 2026. See NOTICE for original-author attribution.

Contributing

We welcome contributions! Please see CONTRIBUTING.md for detailed guidelines on:

• Setting up your development environment
• Making changes and submitting pull requests
• Commit message conventions (Conventional Commits)
• Package management with Lerna
• Publishing packages to GitHub Registry

For release process documentation, see RELEASE.md.