LetsFG — Your AI agent just learned to book flights. (Node.js)

200+ airline connectors. Real prices. One function call. Search 400+ airlines at raw airline prices — $20–$50 cheaper than Booking.com, Kayak, and other OTAs. Zero dependencies. Built for AI agents.

Three ways to use LetsFG

| | Local (this SDK) | letsfg.co (website / agent API) | Developer API | |---|---|---|---| | Search cost | Free | Free | Prepaid credits | | Booking URL | 1% concierge fee (min $3) via letsfg.co | 1% concierge fee (min $3) via letsfg.co | Direct airline URL, no fee | | Speed | 1–15 min (local browsers) | Seconds | Seconds | | Setup | npm install letsfg | letsfg.co | letsfg.co/developers |

Want direct airline URLs without any per-booking fee? Use the Developer API — prepaid credits, results in seconds, no checkout step.

Install

npm install letsfg

Quick Start (SDK)

import { LetsFG, cheapestOffer, offerSummary } from 'letsfg';

// Register (one-time)
const creds = await LetsFG.register('my-agent', '[email protected]');
console.log(creds.api_key); // Save this

// Use
const bt = new LetsFG({ apiKey: 'trav_...' });

// Search — FREE
const flights = await bt.search('GDN', 'BER', '2026-03-03');
const best = cheapestOffer(flights);
console.log(offerSummary(best));

// Unlock
const unlock = await bt.unlock(best.id);

// Book
const booking = await bt.book(
  best.id,
  [{
    id: flights.passenger_ids[0],
    given_name: 'John',
    family_name: 'Doe',
    born_on: '1990-01-15',
    gender: 'm',
    title: 'mr',
    email: '[email protected]',
  }],
  '[email protected]'
);
console.log(`PNR: ${booking.booking_reference}`);

Quick Start (CLI)

export LETSFG_API_KEY=trav_...

letsfg search GDN BER 2026-03-03 --sort price

# Fast mode — OTAs + key airlines only (~25 connectors, 20-40s)
letsfg search GDN BER 2026-03-03 --mode fast
letsfg search LON BCN 2026-04-01 --json  # Machine-readable
letsfg unlock off_xxx
letsfg book off_xxx -p '{"id":"pas_xxx","given_name":"John",...}' -e [email protected]

API

new LetsFG({ apiKey, baseUrl?, timeout? })

bt.search(origin, destination, dateFrom, options?)

bt.resolveLocation(query)

bt.unlock(offerId)

bt.book(offerId, passengers, contactEmail, contactPhone?)

bt.setupPayment(token?)

bt.me()

LetsFG.register(agentName, email, baseUrl?, ownerName?, description?)

Helpers

• offerSummary(offer) — One-line string summary
• cheapestOffer(result) — Get cheapest offer from search

searchLocal(origin, destination, dateFrom, options?)

Search 200 airline connectors locally (no API key needed). Requires Python + letsfg installed.

Note: Local search results return masked booking links by default. Each offer includes offer_ref and payment_token fields. To get a direct airline booking URL, use the concierge unlock flow (1% fee, min $3 — no API key needed) or sign up for the Developer API at letsfg.co/developers for fee-free direct links.

import { searchLocal } from 'letsfg';

const result = await searchLocal('GDN', 'BCN', '2026-06-15');
console.log(result.total_results);

// Limit browser concurrency for constrained environments
const result2 = await searchLocal('GDN', 'BCN', '2026-06-15', { maxBrowsers: 4 });

Unlocking offer results

Local search results include offer_ref and payment_token on each offer. Use these to retrieve the direct airline booking URL via the concierge flow (no API key required):

import { searchLocal } from 'letsfg';

const result = await searchLocal('GDN', 'BCN', '2026-06-15');
const offer = result.offers[0];

// 1. Initiate checkout — fee = max(price × 1%, $3.00). No API key needed.
const checkoutRes = await fetch('https://letsfg.co/api/developers/checkout', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    offer_id:      offer.id,
    offer_ref:     offer.offer_ref,
    payment_token: offer.payment_token,
    currency:      offer.currency,
    price:         String(offer.price),
  }),
});
const { checkout_url } = await checkoutRes.json();

// 2. Present checkout_url to the user (or open it programmatically)
console.log(`Pay here: ${checkout_url}`);

// 3. Poll until payment is confirmed
async function pollVerify(token: string): Promise<string> {
  while (true) {
    await new Promise(r => setTimeout(r, 3000));
    const res = await fetch(
      `https://letsfg.co/api/developers/payment-verify?token=${token}`
    );
    const data = await res.json();
    if (data.verified) return data.booking_url;
  }
}

// 4. booking_url is the direct airline link — no further fees
const bookingUrl = await pollVerify(offer.payment_token);
console.log(`Book here: ${bookingUrl}`);

To skip the per-booking fee entirely, use the Developer API — it returns direct airline booking URLs on every search result.

systemInfo()

Get system resource profile and recommended concurrency settings.

import { systemInfo } from 'letsfg';

const info = await systemInfo();
console.log(info);
// { platform: 'win32', cpu_cores: 16, ram_total_gb: 31.2, ram_available_gb: 14.7,
//   tier: 'standard', recommended_max_browsers: 8, current_max_browsers: 8 }

Zero Dependencies

Uses native fetch (Node 18+). No axios, no node-fetch, nothing. Safe for sandboxed environments.

Performance Tuning

Local search auto-scales browser concurrency based on available RAM. Override with maxBrowsers:

// Limit to 4 concurrent browsers
await searchLocal('LHR', 'BCN', '2026-04-15', { maxBrowsers: 4 });

Or set the LETSFG_MAX_BROWSERS environment variable globally.

Also Available As

• MCP Server: npx letsfg-mcp — npm
• Python SDK + CLI: pip install letsfg — PyPI
• Try without installing: letsfg.co — search instantly in your browser
• GitHub: LetsFG/LetsFG

⭐ Star the repo — we appreciate the support.

License

MIT