DynamoDB scales to basically infinity and costs pennies to start. But if you've built on it with TypeScript, you know the day-to-day is rough:

  • You build partition/sort key strings by hand (USER#${username}) and typo them.
  • You marshal and unmarshal every attribute ({ S: ... }, { N: ... }).
  • You get zero type safety — the SDK returns Record<string, AttributeValue> | undefined and wishes you luck.
  • Single-table design — the thing you're supposed to do — is all in your head.

I got tired of it, so I built Dynatable: a type-safe, functional TypeScript library for Amazon DynamoDB, with first-class single-table design and safe schema migrations. It's built on the AWS SDK v3.

The problem, in code

Here's a simple "get one user" with the raw SDK:

import { DynamoDBClient, GetItemCommand } from '@aws-sdk/client-dynamodb';

const res = await client.send(
  new GetItemCommand({
    TableName: 'MyApp',
    Key: {
      PK: { S: `USER#${username}` },
      SK: { S: 'PROFILE' },
    },
  }),
);

// unmarshall by hand — no types, easy to typo keys
const age = res.Item?.age?.N ? Number(res.Item.age.N) : undefined;

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Keys built by hand. Attributes unwrapped by hand. age is any-ish. Multiply that across every access pattern in your app.

The same thing, with Dynatable 

import { table } from './db';

const user = await table.entities.User
  .get({ username })
  .execute();

// user: User | undefined — fully typed, keys built for you
const age = user?.age;

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Keys are generated from your schema. The result is typed. Done.

Define your schema once

Everything flows from a single schema definition. Types are inferred from it — no code generation step:

import { Table } from '@ftschopp/dynatable-core';
import { DynamoDBClient } from '@aws-sdk/client-dynamodb';

const schema = {
  format: 'dynatable:1.0.0',
  version: '1.0.0',
  indexes: {
    primary: { hash: 'PK', sort: 'SK' },
    gsi1: { hash: 'GSI1PK', sort: 'GSI1SK' },
  },
  models: {
    User: {
      key: {
        PK: { type: String, value: 'USER#${username}' },
        SK: { type: String, value: 'PROFILE' },
      },
      attributes: {
        username: { type: String, required: true },
        email: { type: String },
        age: { type: Number },
        followerCount: { type: Number, default: 0 },
      },
    },
  },
  params: { timestamps: true }, // auto createdAt / updatedAt
} as const;

const table = new Table({
  name: 'MyApp',
  client: new DynamoDBClient({ region: 'us-east-1' }),
  schema,
});

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Fully typed CRUD 

// Create (with a conditional write)
await table.entities.User
  .put({ username: 'alice', email: '[email protected]', age: 30 })
  .ifNotExists()
  .execute();

// Read
const user = await table.entities.User.get({ username: 'alice' }).execute();

// Update — set, add, and return the new item
await table.entities.User
  .update({ username: 'alice' })
  .set('email', '[email protected]')
  .add('followerCount', 1)
  .returning('ALL_NEW')
  .execute();

// Delete
await table.entities.User.delete({ username: 'alice' }).execute();

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The query builder is immutable and chainable, so you can compose queries safely:

// Scan with a typed filter — no raw expression strings
const adults = await table.entities.User
  .scan()
  .filter((a, op) => op.gt(a.age, 18))
  .execute();

const base = table.entities.Post
  .query()
  .where((attr, op) => op.eq(attr.username, 'alice'));

// derive variations without mutating the original
const recent = await base.limit(10).scanIndexForward(false).execute();
const all = await base.execute();

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You also get transactions (TransactWrite), batch operations (BatchGet / BatchWrite), ULID/UUID generation, and runtime Zod validation on put():

await table.entities.User.put({
  username: 'alice',
  age: '30', // ❌ throws ZodError: Expected number, got string
}).execute();

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Single-table design, first-class

Model many entities in one table the DynamoDB way — composite keys, GSIs, one-to-many and many-to-many — without hand-writing key strings. That's the whole point of the library, not an afterthought.

The part nobody talks about: migrations

DynamoDB is schemaless, but your data still has a shape. When you need to add a field, reshape a key, or backfill data across environments, you want that to be as safe as a code change.

@ftschopp/dynatable-migrations gives you versioned, reversible migrations with a full CLI:

# scaffold migrations in your project
npx dynatable-migrate init

# create a versioned migration (semver bump)
npx dynatable-migrate create add_user_email --type minor

# preview changes — nothing is written
npx dynatable-migrate up --dry-run

# apply: distributed lock + history stored in your table
npx dynatable-migrate up

# roll back if you need to
npx dynatable-migrate down --steps 1

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A migration is just an up/down pair:

import { Migration } from '@ftschopp/dynatable-migrations';

export const migration: Migration = {
  version: '0.2.0',
  name: 'add_user_email',
  description: 'Backfill email on existing users',
  async up({ client, tableName, dynamodb }) {
    // scan + update items here
  },
  async down({ client, tableName, dynamodb }) {
    // reverse it
  },
};

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Migration history lives inside your existing table (single-table style) — no extra tracking table, plus dry-run mode and distributed locking so two deploys never race.

Why Dynatable

  • 🛡️ End-to-end type safety — inferred from your schema, no codegen
  • 📊 Single-table design built in — GSIs, composite keys, relationships
  • 🔍 Fluent, immutable query builder — no raw expression strings
  • 🔄 Safe schema migrations — up/down, dry-run, locking, CLI
  • ✅ Runtime validation with Zod on writes
  • 🧱 No decorators, no classes — plain, immutable TypeScript objects
  • 🚀 Built on AWS SDK v3 — transactions, batch, conditional writes

Get started 

npm install @ftschopp/dynatable-core
# migrations (optional)
npm install -D @ftschopp/dynatable-migrations

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If you've ever hand-written a USER#${id} key at 2am, give it a try — and if it saves you some pain, a ⭐ on GitHub genuinely helps.

What would you want a DynamoDB library to handle for you? Let me know in the comments.