Remult

Full-stack CRUD, simplified, with SSOT TypeScript entities

Remult is a full-stack CRUD framework that uses your TypeScript entities as a single source of truth for your API, frontend type-safe API client and backend ORM.

• ⚡ Zero-boilerplate CRUD API routes with paging, sorting, and filtering for Express / Fastify / Next.js / NestJS / Koa / others...
• 👌 Fullstack type-safety for API queries, mutations and RPC, without code generation
• ✨ Input validation, defined once, runs both on the backend and on the frontend for best UX
• 🔒 Fine-grained code-based API authorization
• 😌 Incrementally adoptable
• 🚀 Production ready
• 📣 NEW - Zero-boilerplate realtime live-queries

Remult is production-ready and, in fact, used in production apps since 2018. However, we’re keeping the major version at zero so we can use community feedback to finalize the v1 API.

Full-stack web development is (still) too complicated. Simple CRUD, a common requirement of any business application, should be simple to build, maintain, and extend when the need arises.

Remult abstracts away repetitive, boilerplate, error-prone, and poorly designed code on the one hand, and enables total flexibility and control on the other. Remult helps building fullstack apps using only TypeScript code you can easily follow and safely refactor, and fits nicely into any existing or new project by being minimalistic and completely unopinionated regarding the developer’s choice of other frameworks and tools.

Other frameworks tend to fall into either too much abstraction (no-code, low-code, BaaS) or partial abstraction (MVC frameworks, GraphQL, ORMs, API generators, code generators), and tend to be opinionated regarding the development tool-chain, deployment environment, configuration/conventions or DSL. Remult attempts to strike a better balance.

The remult package is one and the same for both the frontend bundle and the backend. Install it once for a monolith project or per-repo in a monorepo.

npm i remult

// shared/product.ts

import { Entity, Fields } from "remult"

@Entity("products", {
  allowApiCrud: true
})
export class Product {
  @Fields.string()
  name = ""

  @Fields.number()
  unitPrice = 0
}

// backend/index.ts

import express from "express"
import { remultExpress } from "remult/remult-express"
import { Product } from "../shared/product"

const port = 3001
const app = express()

app.use(
  remultExpress({
    entities: [Product]
  })
)

app.listen(port, () => {
  console.log(`Example API listening at https://localhost:${port}`)
})

> curl https://localhost:3001/api/products

[{"name":"Tofu","unitPrice":5}]

// frontend/code.ts

import { remult } from "remult"
import { Product } from "../shared/product"

async function increasePriceOfTofu(priceIncrease: number) {
  const productsRepo = remult.repo(Product)

  const product = await productsRepo.findFirst({ name: "Tofu" }) // filter is passed through API request all the way to the db
  product.unitPrice += priceIncrease
  productsRepo.save(product) // mutation request updates the db with no boilerplate code
}

@BackendMethod({ allowed: Allow.authenticated })
static async increasePriceOfTofu(priceIncrease: number) {
  const productsRepo = remult.repo(Product);

  const product = await productsRepo.findFirst({ name: 'Tofu' }); // use Remult in the backend as an ORM
  product.unitPrice += priceIncrease;
  productsRepo.save(product);
}

import { Entity, Fields, Validators } from "remult"

@Entity("products", {
  allowApiCrud: true
})
export class Product {
  @Fields.string({
    validate: Validators.required
  })
  name = ""

  @Fields.string<Product>({
    validate: (product) => {
      if (product.description.trim().length < 50) {
        throw "too short"
      }
    }
  })
  description = ""

  @Fields.number({
    validate: (_, field) => {
      if (field.value < 0) {
        field.error = "must not be less than 0" // or: throw "must not be less than 0";
      }
    }
  })
  unitPrice = 0
}

const product = productsRepo.create()

try {
  await productsRepo.save(product)
} catch (e: any) {
  console.error(e.message) // Browser console will display - "Name: required"
}

> curl https://localhost:3001/api/products -H "Content-Type: application/json" -d "{""unitPrice"":-1}"

{"modelState":{"unitPrice":"must not be less than 0","name":"required"},"message":"Name: required"}

@Entity<Article>("Articles", {
  allowApiRead: true,
  allowApiInsert: (_, remult) => remult.authenticated(),
  allowApiUpdate: (article, remult) => article.author.id == remult.user.id
})
export class Article {
  @Fields.string({ allowApiUpdate: false })
  slug = ""

  @Field(() => Profile, { allowApiUpdate: false })
  author!: Profile

  @Fields.string()
  content = ""
}

While simple CRUD shouldn’t require any backend coding, using Remult means having the ability to handle any complex scenario by controlling the backend in numerous ways:

• Backend computed (read-only) fields - from simple expressions to complex data lookups or even direct db access (SQL)
• Custom side-effects with entity lifecycle hooks (before/after saving/deleting)
• Backend only updatable fields (e.g. “last updated at”)
• Many-to-one relations with lazy/eager loading
• Roll-your-own type-safe endpoints with Backend Methods
• Roll-your-own low-level endpoints (Express, Fastify, koa, others…)

The best way to learn Remult is by following a tutorial of a simple Todo web app with a Node.js Express backend.

• Tutorial with React
• Tutorial with Angular
• Tutorial with Vue
• Tutorial with Next.js

The documentation covers the main features of Remult. However, it is still a work-in-progress.

• Fullstack TodoMVC example with React and Express. (Source code | CodeSandbox)

• CRM demo with a React + MUI front-end and Postgres database.

Contributions are welcome. See CONTRIBUTING.md.

• 💬 Any feedback or suggestions? Start a discussion.
• 💪 Want to help out? Look for "help wanted" labeled issues.
• ⭐ Give this repo a star.

Remult is MIT Licensed.