N2YO TypeScript Client

A strongly-typed, feature-complete TypeScript client for the N2YO.com satellite tracking API with comprehensive type safety and developer experience.

Features ✨

• Full API Coverage: All N2YO API endpoints with proper TypeScript typings
• Type Safety: Strict TypeScript types for all requests and responses
• Error Handling: Custom error classes for different failure scenarios
• Utility Functions: Helpers for working with TLE data and timestamps
• Well Documented: Comprehensive JSDoc comments and examples
• Modern JS/TS: ES Modules, async/await, and modern TypeScript features

Installation 📦

# npm
npm install n2yo-ts

# yarn
yarn add n2yo-ts

# pnpm
pnpm add n2yo-ts

Getting Started 🚀

First, obtain your API key from N2YO.com.

Basic Usage Example

import { N2YOClient } from 'n2yo-ts'

const client = new N2YOClient('YOUR_API_KEY', { debug: true })

// Fetch TLE for the ISS
const tle = await client.getTleByName('ISS')
console.log(tle.tle) // e.g., "1 25544U 98067A   ..."

// Predict ISS positions for the next 60 seconds
const positions = await client.getPositions(25544, 40.7128, -74.006, 0, 60)
console.log(positions.positions) // Array of positions

// Get visual passes for the ISS
const passes = await client.getVisualPasses(25544, 40.7128, -74.006, 0, 7, 30)
console.log(passes.passes) // Array of passes

// Convert UTC timestamp to local time
const localTime = client.utcToLocal(1711987840, 'America/New_York')
console.log(localTime) // e.g., "2024-04-01 15:30:40"

Configuration ⚙

const client = new N2YOClient('YOUR_API_KEY', {
  debug: true,
})

API Reference 📚

Client Methods

getTle(noradId: number)

Retrieve Two-Line Element (TLE) data for a satellite.

const tle = await client.getTle(25544) // ISS

getPositions(noradId: number, latitude: number, longitude: number, altitude: number, seconds: number)

Get satellite positions over time.

// Get ISS positions for next 5 minutes over London
const positions = await client.getPositions(25544, 51.5074, -0.1278, 0, 300)

getVisualPasses(noradId: number, latitude: number, longitude: number, altitude: number, days: number, minVisibility: number)

Predict visible satellite passes.

// Get visible ISS passes over Tokyo in next 3 days (minimum 5 minutes visibility)
const passes = await client.getVisualPasses(25544, 35.6762, 139.6503, 0, 3, 300)

getRadioPasses(noradId: number, latitude: number, longitude: number, altitude: number, days: number, minElevation: number)

Predict radio-visible satellite passes.

// Get radio passes for amateur radio satellite over Berlin
const passes = await client.getRadioPasses(42784, 52.52, 13.405, 0, 7, 30)

getAbove(latitude: number, longitude: number, altitude: number, searchRadius: number, categoryId?: number)

Find satellites currently overhead.

// Find all Starlink satellites above a 90-degree radius
const starlinks = await client.getAbove(34.0522, -118.2437, 0, 90, 52)

Utility Functions

import {
  calculateDistance,
  getAllCategories,
  splitTle,
  timestampToDate,
} from 'n2yo-ts'

// Split TLE into separate lines
const [line1, line2] = splitTle('1 25544U...\r\n2 25544...')

// Convert UNIX timestamp to Date object
const passTime = timestampToDate(1719878400)

// Get all satellite categories
const categories = getAllCategories()

const distance = calculateDistance(
  { lat: 40.7128, lng: -74.006 }, // New York City
  { lat: 51.5074, lng: -0.1278 }, // London
)
// Returns ~5570 km

Error Handling ⚠️

The library provides specific error classes:

Error Class	Description
N2YOError	Base error class for all N2YO errors
RateLimitError	Thrown when API rate limit is exceeded
InvalidParameterError	Thrown when invalid parameters are provided

try {
  await client.getPositions(25544, 91, 0, 0, 60) // Invalid latitude
} catch (error) {
  if (error instanceof InvalidParameterError) {
    console.error('Invalid parameter:', error.message)
  } else if (error instanceof RateLimitError) {
    console.error('Slow down! You hit the rate limit')
  } else {
    console.error('Unexpected error:', error)
  }
}

Rate Limits ⏱️

N2YO enforces the following rate limits:

Endpoint	Limit
Positions	1,000 requests/hour
Visual Passes	100 requests/hour
Radio Passes	100 requests/hour
Above	100 requests/hour

The client doesn't implement rate limiting internally - you should implement your own throttling.

Advanced Usage 🧠

TypeScript Types

All API response types are exported for your convenience:

import type { PositionsResponse, SatellitePass, TleResponse } from 'n2yo-ts'

function logPassDetails(pass: SatellitePass) {
  console.log(`Pass starts at ${new Date(pass.startUTC * 1000)}`)
}

Satellite Categories

The complete list of satellite categories is available:

import { SatelliteCategories } from 'n2yo-ts'

console.log(SatelliteCategories[18]) // "Amateur radio"

Command-Line Interface (CLI) 🖥️

The n2yo-ts package includes a powerful CLI for interacting with the N2YO API directly from your terminal. Install it globally to use the n2yo-ts command:

# Install globally with npm
npm install n2yo-ts -g

# Or with pnpm
pnpm install n2yo-ts -g

# Or with yarn
yarn global add n2yo-ts

CLI Usage

Run n2yo-ts --help to see all available commands and options. The CLI requires an N2YO API key, which you can obtain from N2YO.com. You can provide the API key in several ways:

1. Command-line option (highest priority):

n2yo-ts <command> --apiKey <your-api-key> [options]

2. Enviroment variable: Set the N2YO_API_KEY enviroment variable:

export N2YO_API_KEY=your-api-key
n2yo-ts <command> [options]

3. Configuration file: Create a file at ~/.n2yo-ts/config.json with the following content:

{ "apiKey": "your-api-key" }

Then run:

n2yo-ts <command> [options]

4. Interactive prompt: If no API key is provided via the above methods, the CLI will prompt you to enter it.

Global Options:

• --apiKey <key>: Your N2YO API key (required).
• -v, --verbose: Enable verbose output for debugging (optional).

Commands

tle --sat <name|noradId>

Retrieve the Two-Line Element (TLE) data for a satellite by its common name (e.g., ISS, HUBBLE) or NORAD ID.

n2yo-ts tle --sat ISS

Output:

TLE for ISS (ZARYA) (NORAD 25544)
1 25544U 98067A   24245.12345678  .00002134  00000-0  45678-4 0  9999
2 25544  51.6456 123.4567 0001234 123.4567 234.5678 15.12345678901234

positions --sat <name|noradId> --lat <latitude> --lng <longitude> [--alt <altitude>] [--seconds <seconds>]

Predict satellite positions for the specified location and time window.

• --sat <name|noradId>: Satellite name (e.g., ISS) or NORAD ID (required).
• --lat <latitude>: Observer latitude (-90 to 90 degrees, required).
• --lng <longitude>: Observer longitude (-180 to 180 degrees, required).
• --alt <altitude>: Observer altitude in meters (default: 0).
• --seconds <seconds>: Seconds of prediction (0–300, default: 60).

n2yo-ts positions --sat ISS --lat 40.7128 --lng -74.006 --alt 0 --seconds 60

Output:

Positions for ISS (ZARYA) (NORAD 25544):
Time: 2025-08-01 23:17:00 UTC, Lat: 40.12, Lng: -73.45, Alt: 420.34 km, Distance: 557.23 km
Time: 2025-08-01 23:17:01 UTC, Lat: 40.13, Lng: -73.44, Alt: 420.35 km, Distance: 556.89 km
...

visualpasses --sat <name|noradId> --lat <latitude> --lng <longitude> [--alt <altitude>] [--days <days>] [--min-visibility <seconds>] [--tz <timezone>]

Predict visible (sunlit) satellite passes for the specified location.

• --sat <name|noradId>: Satellite name or NORAD ID (required).
• --lat <latitude>: Observer latitude (-90 to 90 degrees, required).
• --lng <longitude>: Observer longitude (-180 to 180 degrees, required).
• --alt <altitude>: Observer altitude in meters (default: 0).
• --days <days>: Prediction window in days (1–10, default: 1).
• --min-visibility <seconds>: Minimum pass duration in seconds (default: 300).
• --tz <timezone>: Time zone for output (e.g., America/New_York, default: UTC).

n2yo-ts visualpasses --sat ISS --lat 35.6762 --lng 139.6503 --days 3 --min-visibility 300 --tz Asia/Tokyo

Output:

Visual passes for ISS (ZARYA) (NORAD 25544):
Start: 2025-08-02 20:15:30 Asia/Tokyo, End: 2025-08-02 20:21:45, Duration: 375s, Max Elevation: 45°, Magnitude: -2.5
...

radiopasses --sat <name|noradId> --lat <latitude> --lng <longitude> [--alt <altitude>] [--days <days>] [--min-elevation <degrees>] [--tz <timezone>]

Predict radio passes (no sunlight requirement) for the specified location.

• --sat <name|noradId>: Satellite name or NORAD ID (required).
• --lat <latitude>: Observer latitude (-90 to 90 degrees, required).
• --lng <longitude>: Observer longitude (-180 to 180 degrees, required).
• --alt <altitude>: Observer altitude in meters (default: 0).
• --days <days>: Prediction window in days (1–10, default: 1).
• --min-elevation <degrees>: Minimum max elevation in degrees (default: 0).
• --tz <timezone>: Time zone for output (e.g., America/New_York, default: UTC).

n2yo-ts radiopasses --sat 42784 --lat 52.52 --lng 13.405 --days 7 --min-elevation 30 --tz Europe/Berlin

Output:

Radio passes for AO-91 (NORAD 42784):
Start: 2025-08-02 14:30:00 Europe/Berlin, End: 2025-08-02 14:40:00, Max Elevation: 35°
...

above --lat <latitude> --lng <longitude> [--alt <altitude>] [--radius <degrees>] [--category <id>]

List satellites currently above a location.

• --lat <latitude>: Observer latitude (-90 to 90 degrees, required).
• --lng <longitude>: Observer longitude (-180 to 180 degrees, required).
• --alt <altitude>: Observer altitude in meters (default: 0).
• --radius <degrees>: Search radius in degrees (0–90, default: 90).
• --category <id>: Satellite category ID (0 for all, default: 1).

n2yo-ts above --lat 34.0522 --lng -118.2437 --radius 90 --category 52

Output:

Satellites above (Category: Starlink):
STARLINK-1234 (NORAD 45678): Lat: 34.10, Lng: -118.20, Alt: 550.00 km, Distance: 25.67 km
...

Error Handling

The CLI handles errors gracefully and provides clear messages:

• RateLimitError: "Rate limit exceeded"
• InvalidParameterError: "Invalid parameter"
• N2YOError: "API request failed"
• Other Errors: Descriptive error message

If an error occurs, the CLI exits with a non-zero status code.

Contributing 🤝

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Push to the branch
5. Open a pull request

License

MIT License © 2025 Daniel