GitHub - supabase/iceberg-js: A small, framework-agnostic JavaScript/TypeScript client for the Apache Iceberg REST Catalog.

iceberg-js

A small, framework-agnostic JavaScript/TypeScript client for the Apache Iceberg REST Catalog.

Motivation

This library provides JavaScript and TypeScript developers with a straightforward way to interact with Apache Iceberg REST Catalogs. It's designed as a thin HTTP wrapper that mirrors the official REST API, making it easy to manage namespaces and tables from any JS/TS environment.

Goals

• REST API wrapper: Provide a 1:1 mapping to the Iceberg REST Catalog API
• Type safety: Full TypeScript support with strongly-typed request/response models
• Minimal footprint: No engine-specific logic, no heavy dependencies
• Stability: Production-ready for catalog management operations
• Vendor-agnostic: Works with any Iceberg REST Catalog implementation

Non-Goals

This library intentionally does not support:

• Data operations: Reading or writing table data (Parquet files, etc.)
• Query execution: Use dedicated query engines (Spark, Trino, DuckDB, etc.)
• Engine integration: No Spark, Flink, or other engine-specific code
• Advanced features: Branching, tagging, time travel queries beyond metadata
• Views or multi-table transactions

These boundaries keep the library focused and maintainable. For data operations, pair this library with a query engine that supports Iceberg.

Features

• Generic: Works with any Iceberg REST Catalog implementation, not tied to any specific vendor
• Minimal: Thin HTTP wrapper over the official REST API, no engine-specific logic
• Type-safe: First-class TypeScript support with strongly-typed request/response models
• Fetch-based: Uses native fetch API with support for custom implementations
• Universal: Targets Node 20+ and modern browsers (ES2020)
• Catalog-only: Focused on catalog operations (no data reading/Parquet support in v0.1.0)

Documentation

📚 Full API documentation: supabase.github.io/iceberg-js

Installation

Quick Start

import { IcebergRestCatalog } from 'iceberg-js'

const catalog = new IcebergRestCatalog({
  baseUrl: 'https://my-catalog.example.com/iceberg/v1',
  auth: {
    type: 'bearer',
    token: process.env.ICEBERG_TOKEN,
  },
})

// Create a namespace
await catalog.createNamespace({ namespace: ['analytics'] })

// Create a table
await catalog.createTable(
  { namespace: ['analytics'] },
  {
    name: 'events',
    schema: {
      type: 'struct',
      fields: [
        { id: 1, name: 'id', type: 'long', required: true },
        { id: 2, name: 'timestamp', type: 'timestamp', required: true },
        { id: 3, name: 'user_id', type: 'string', required: false },
      ],
      'schema-id': 0,
      'identifier-field-ids': [1],
    },
    'partition-spec': {
      'spec-id': 0,
      fields: [],
    },
    'write-order': {
      'order-id': 0,
      fields: [],
    },
    properties: {
      'write.format.default': 'parquet',
    },
  }
)

API Reference

Constructor

new IcebergRestCatalog(options)

Creates a new catalog client instance.

Options:

• baseUrl (string, required): Base URL of the REST catalog
• auth (AuthConfig, optional): Authentication configuration
• catalogName (string, optional): Catalog name for multi-catalog servers. When specified, requests are sent to {baseUrl}/v1/{catalogName}/.... For example, with baseUrl: 'https://host.com' and catalogName: 'prod', requests go to https://host.com/v1/prod/namespaces
• fetch (typeof fetch, optional): Custom fetch implementation
• accessDelegation (AccessDelegation[], optional): Access delegation mechanisms to request from the server

Authentication types:

// No authentication
{ type: 'none' }

// Bearer token
{ type: 'bearer', token: 'your-token' }

// Custom header
{ type: 'header', name: 'X-Custom-Auth', value: 'secret' }

// Custom function
{ type: 'custom', getHeaders: async () => ({ 'Authorization': 'Bearer ...' }) }

Access Delegation:

Access delegation allows the catalog server to provide temporary credentials or sign requests on your behalf:

import { IcebergRestCatalog } from 'iceberg-js'

const catalog = new IcebergRestCatalog({
  baseUrl: 'https://catalog.example.com/iceberg/v1',
  auth: { type: 'bearer', token: 'your-token' },
  // Request vended credentials for data access
  accessDelegation: ['vended-credentials'],
})

// The server may return temporary credentials in the table metadata
const metadata = await catalog.loadTable({ namespace: ['analytics'], name: 'events' })
// Use credentials from metadata.config to access table data files

Supported delegation mechanisms:

• vended-credentials: Server provides temporary credentials (e.g., AWS STS tokens) for accessing table data
• remote-signing: Server signs data access requests on behalf of the client

Namespace Operations

listNamespaces(parent?: NamespaceIdentifier): Promise<NamespaceIdentifier[]>

List all namespaces, optionally under a parent namespace.

const namespaces = await catalog.listNamespaces()
// [{ namespace: ['default'] }, { namespace: ['analytics'] }]

const children = await catalog.listNamespaces({ namespace: ['analytics'] })
// [{ namespace: ['analytics', 'prod'] }]

createNamespace(id: NamespaceIdentifier, metadata?: NamespaceMetadata): Promise<void>

Create a new namespace with optional properties.

await catalog.createNamespace({ namespace: ['analytics'] }, { properties: { owner: 'data-team' } })

dropNamespace(id: NamespaceIdentifier): Promise<void>

Drop a namespace. The namespace must be empty.

await catalog.dropNamespace({ namespace: ['analytics'] })

loadNamespaceMetadata(id: NamespaceIdentifier): Promise<NamespaceMetadata>

Load namespace metadata and properties.

const metadata = await catalog.loadNamespaceMetadata({ namespace: ['analytics'] })
// { properties: { owner: 'data-team', ... } }

Table Operations

listTables(namespace: NamespaceIdentifier): Promise<TableIdentifier[]>

List all tables in a namespace.

const tables = await catalog.listTables({ namespace: ['analytics'] })
// [{ namespace: ['analytics'], name: 'events' }]

createTable(namespace: NamespaceIdentifier, request: CreateTableRequest): Promise<TableMetadata>

Create a new table.

const metadata = await catalog.createTable(
  { namespace: ['analytics'] },
  {
    name: 'events',
    schema: {
      type: 'struct',
      fields: [
        { id: 1, name: 'id', type: 'long', required: true },
        { id: 2, name: 'timestamp', type: 'timestamp', required: true },
      ],
      'schema-id': 0,
    },
    'partition-spec': {
      'spec-id': 0,
      fields: [
        {
          source_id: 2,
          field_id: 1000,
          name: 'ts_day',
          transform: 'day',
        },
      ],
    },
  }
)

loadTable(id: TableIdentifier): Promise<TableMetadata>

Load table metadata.

const metadata = await catalog.loadTable({
  namespace: ['analytics'],
  name: 'events',
})

updateTable(id: TableIdentifier, request: UpdateTableRequest): Promise<CommitTableResponse>

Update table metadata (schema, partition spec, or properties).

const updated = await catalog.updateTable(
  { namespace: ['analytics'], name: 'events' },
  {
    properties: { 'read.split.target-size': '134217728' },
  }
)

dropTable(id: TableIdentifier): Promise<void>

Drop a table from the catalog.

await catalog.dropTable({ namespace: ['analytics'], name: 'events' })

Error Handling

All API errors throw an IcebergError with details from the server:

import { IcebergError } from 'iceberg-js'

try {
  await catalog.loadTable({ namespace: ['test'], name: 'missing' })
} catch (error) {
  if (error instanceof IcebergError) {
    console.log(error.status) // 404
    console.log(error.icebergType) // 'NoSuchTableException'
    console.log(error.message) // 'Table does not exist'
  }
}

TypeScript Types

The library exports all relevant types:

import type {
  NamespaceIdentifier,
  TableIdentifier,
  TableSchema,
  TableField,
  IcebergType,
  PartitionSpec,
  SortOrder,
  CreateTableRequest,
  TableMetadata,
  AuthConfig,
  AccessDelegation,
} from 'iceberg-js'

Supported Iceberg Types

The following Iceberg primitive types are supported:

• boolean, int, long, float, double
• string, uuid, binary
• date, time, timestamp, timestamptz
• decimal(precision, scale), fixed(length)

Compatibility

This package is built to work in all Node.js and JavaScript environments:

Package exports:

• ESM: dist/index.mjs with dist/index.d.ts
• CommonJS: dist/index.cjs with dist/index.d.cts
• Proper exports field for Node.js 12+ module resolution

All scenarios are tested in CI on Node.js 20 and 22.

Browser Usage

The library works in modern browsers that support native fetch:

import { IcebergRestCatalog } from 'iceberg-js'

const catalog = new IcebergRestCatalog({
  baseUrl: 'https://public-catalog.example.com/iceberg/v1',
  auth: { type: 'none' },
})

const namespaces = await catalog.listNamespaces()

Node.js Usage

Node.js 20+ includes native fetch support. For older versions, provide a custom fetch implementation:

import { IcebergRestCatalog } from 'iceberg-js'
import fetch from 'node-fetch'

const catalog = new IcebergRestCatalog({
  baseUrl: 'https://catalog.example.com/iceberg/v1',
  auth: { type: 'bearer', token: 'token' },
  fetch: fetch as any,
})

Development

# Install dependencies
pnpm install

# Build the library
pnpm run build

# Run unit tests
pnpm test

# Run integration tests (requires Docker)
pnpm test:integration

# Run integration tests with cleanup (for CI)
pnpm test:integration:ci

# Run compatibility tests (all module systems)
pnpm test:compatibility

# Format code
pnpm run format

# Lint and test
pnpm run check

Testing with Docker

Integration tests run against a local Iceberg REST Catalog in Docker. See TESTING-DOCKER.md for details.

# Start Docker services and run integration tests
pnpm test:integration

# Or manually
docker compose up -d
npx tsx test/integration/test-local-catalog.ts
docker compose down -v

Compatibility Testing

The test:compatibility script verifies the package works correctly in all JavaScript/TypeScript environments:

• Pure JavaScript ESM - Projects with "type": "module"
• Pure JavaScript CommonJS - Traditional Node.js projects
• TypeScript ESM - TypeScript with module: "ESNext"
• TypeScript CommonJS - TypeScript with module: "CommonJS"

These tests ensure proper module resolution, type definitions, and runtime behavior across all supported environments. See test/compatibility/README.md for more details.

License

MIT

Releases

This project uses release-please for automated releases. Here's how it works:

1. Commit with conventional commits: Use Conventional Commits format for your commits:

   • feat: for new features (minor version bump)
   • fix: for bug fixes (patch version bump)
   • feat!: or BREAKING CHANGE: for breaking changes (major version bump)
   • chore:, docs:, test:, etc. for non-release commits

2. Release PR is created automatically: When you push to main, release-please creates/updates a release PR with:

   • Version bump in package.json
   • Updated CHANGELOG.md
   • Release notes

3. Merge the release PR: When you're ready to release, merge the PR. This will:

   • Create a GitHub release and git tag
   • Automatically publish to npm with provenance (using trusted publishing, no secrets needed)

Example commits:

git commit -m "feat: add support for view operations"
git commit -m "fix: handle empty namespace list correctly"
git commit -m "feat!: change auth config structure"

Contributing

Contributions are welcome! Please ensure your contributions align with the library's goals and non-goals. This library aims to remain a minimal, generic client for the Iceberg REST Catalog API.