letsfg/letsfg

MPP (updated 2026-07-30): the MPP (Machine Payments Protocol) 402 challenge is live, as a card-free enrolment lane for agents holding a Tempo wallet. It costs $0.01 once, as verification only — MPP has no zero-amount intent, so a card-free rail has to settle something. Search and booking stay free. Earlier revisions of this page described an MPP charge at unlock time; that never shipped. See .

⚠️ Agents: do not create a Developer API account

Do NOT call /developers/api/v1/agents/register or /developers/api/v1/agents/setup-payment, and do NOT run letsfg register or letsfg setup-payment. Those belong to a separate, paid, prepaid-balance product for high-volume commercial integrations and create a billing account you almost certainly do not want.

To search and book flights, run letsfg auth — a zero-amount card setup (nothing charged), then search and book. See .

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🏨 Hotels — new, and live

Your agent can now book hotels, not just flights. Same API key, same card on file.

from letsfg import LetsFG
lfg = LetsFG()

city = lfg.hotel_destinations("Warsaw")[0]
stays = lfg.search_hotels(
    city_id=city["Id"], city_name=city["Name"],
    check_in="2026-11-10", check_out="2026-11-12", adults=2,
)

hotel = stays["hotels"][0]
offer = hotel["offers"][0]
print(hotel["name"], offer["price"], stays["currency"])
# Hotel Gromada Warszawa Centrum 669.86 PLN

booking = lfg.book_hotel_and_wait(
    session_id=stays["session_id"],
    hotel_code=hotel["hotel_code"],
    combination_id_v2=offer["combination_id_v2"],
    expected_price=offer["price"],
    expected_balance=offer["balance_to_supplier"],
    city_id=city["Id"], city_name=city["Name"],
    check_in="2026-11-10", check_out="2026-11-12",
    guests=[{"title": "Mr", "first_name": "Jan", "last_name": "Kowalski"}],
    email="[email protected]", phone="512345678",
)
print(booking["confirmation"], booking["pay_link"])

How you pay

10% now, the rest to the hotel later. At booking we charge 10% of the price to your card as a reservation fee. The remaining balance is paid directly to the supplier through a pay_link we return — we never hold it.

balance_due_by is the supplier’s own auto-cancellation date, not a date we invent. Miss it and the room is released.

The 10% is non-refundable. Cancelling before balance_due_by costs nothing else; after it, the hotel’s own cancellation ladder applies and can reach 100%. That ladder ships in the booking’s terms, so you can always see the cost before you cancel.

Things worth knowing before you build

• A card on file is required for every hotel call, including search. That is unusual and it is deliberate: a hotel search opens a real session at the supplier, and booking blocks a real rate. We would rather refuse up front than let you reach the point of commitment and discover you cannot pay. The same card that authorises flight booking authorises hotels — there is no separate hotel signup.
• Only free-cancellation, pay-later rates are sold. Those are the rates where the balance can safely be settled with the supplier after booking, which is what makes 10%-now/rest-later work at all. You will see fewer results than a metasearch shows you. Every one of them can actually be booked.
• Booking is asynchronous. book_hotel returns a booking_job_id, not a booking — the real thing takes minutes. Poll hotel_booking(job_id) until status is succeeded or failed, or call book_hotel_and_wait and let the SDK do it. This is not ceremony: it is what makes it impossible to charge a card and then lose the confirmation to a timeout.
• The fee is charged before the room is committed. A declined card therefore costs nothing to unwind — no reservation exists and nothing is charged.
• Do not retry a booking blindly. Calling book_hotel twice for the same rate books the room twice and charges two reservation fees.
• price is what the guest pays. There is no wholesale figure in the response to quote by mistake.

JavaScript

import { LetsFG } from 'letsfg';
const lfg = new LetsFG({ apiKey: process.env.LETSFG_API_KEY });

const [city] = await lfg.hotelDestinations('Warsaw');
const stays = await lfg.searchHotels({
  cityId: city.Id, cityName: city.Name,
  checkIn: '2026-11-10', checkOut: '2026-11-12', adults: 2,
});

const booking = await lfg.bookHotelAndWait({ /* ...offer + guest details... */ });
console.log(booking.confirmation, booking.pay_link);

MCP

Five new tools, in the order you call them: resolve_hotel_city → search_hotels → book_hotel → get_hotel_booking → cancel_hotel_booking.

Three ways to use LetsFG

• CLI / SDK (Path 1): pip install letsfg and run letsfg auth once — it puts a payment method on file via a zero-amount Stripe setup (no charge, no authorization hold) and gives you a 90-day Bearer token. After that, letsfg search calls our server-side engine and applies the open-source ranking algorithm locally. Search is free and unlimited.

• PFS — Programmatic Flight Search (Path 2): For scripts and agents that call the API directly. letsfg.co is human-only by default (Cloudflare Turnstile + bot protection). Get a 90-day Bearer token by putting a payment method on file. Nothing is charged on the card lanes — it is a zero-amount Stripe setup:

  1. POST https://letsfg.co/api/agent-access/request → 402 with setup_url (hosted), a headless object, and an mpp object
  2. Present a payment method, whichever fits how you run:
     • hosted — a human adds a card at setup_url, then send { "setup_session_id": "cs_..." }
     • headless — no browser: create a PaymentMethod and confirm the SetupIntent yourself against api.stripe.com with the supplied publishable key, then send { "setup_intent_id": "seti_..." }
     • MPP — no card at all: answer the WWW-Authenticate: Payment challenge ($0.01 once, verification only), then retry with Authorization: Payment
  3. POST https://letsfg.co/api/agent-access/verify → receive your Bearer token
  4. Search: POST https://letsfg.co/api/search with Authorization: Bearer
  5. Book: POST https://letsfg.co/api/agent-book

  Full guide and response schema: letsfg.co/for-agents. Booking returns either a confirmed order or a direct booking link for that exact offer.

• Developer API (Path 3): Paid server-side search at letsfg.co/developers. Prepaid credits, direct airline booking URLs (no checkout step), full NL query parsing, and a /discover endpoint that checks 20 destinations in one call for 1 credit (2–5 s). Includes a free sandbox at /sandbox/flights/*. Full docs: letsfg.co/developers/api/docs.

Free server-side search: Use Path 1 or PFS — one letsfg auth (a zero-amount card setup, nothing charged) gives you a 90-day token and free searches on our servers. No Playwright, no local install beyond the SDK. Direct booking URLs with no per-booking fee: Use the Developer API (Path 3) — prepaid credits, instant results, no checkout layer.

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Real prices: LetsFG vs Google Flights

We searched 5 routes on Google Flights and LetsFG on the same day (2026-08-05), for flights departing 2026-09-16. Same airline, same number of stops — LetsFG was cheaper every time:

$133 cheaper across 5 routes in a verified comparison (2026-08-05). Google Flights inflates on repeat searches; LetsFG returns the same prices however often you run the search, because it reads airlines and the major booking sites directly rather than tracking you.

Why the difference? Google Flights only searches its own limited set of airline partners. LetsFG searches everywhere — Skyscanner, Kiwi, Kayak, Momondo, plus direct airline websites (Ryanair, United, Southwest, EasyJet, Spirit, Norwegian, AirAsia, and hundreds more). More sources = better prices. No demand-based inflation and no cookie tracking: the same search returns the same prices however often you run it.

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Real hotel prices: LetsFG vs Booking.com

Same hotel, same room type, same 2-night stay, same free-cancellation policy — checked on the same day (2026-08-05) for a 2026-09-16 check-in:

$207 cheaper across 3 hotels in a verified comparison (2026-08-05), matching each property’s own free-cancellation rate against Booking.com’s free-cancellation rate for the identical dates and room type. Prices quoted in PLN at booking, converted to USD at that day’s rate.

Why the difference? LetsFG sells at wholesale cost — no markup for demand, no loyalty-program cross-subsidy. You’re not paying for the room upfront: 10% books it now, and the remaining 90% isn’t due until the hotel’s own cancellation deadline. Cancel before that deadline and you lose nothing but the 10%; the rest was never charged. Only free-cancellation, pay-later rates are sold, so every price shown is one you can actually hold risk-free.

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Try it right now — no install needed

Human users: Use letsfg.co and search flights instantly in your browser:

Search any route, compare live results, and unlock the booking links for the flights you want — no installation needed.

Agents / scripts (free server-side): Get a Bearer token by putting a payment method on file (nothing is charged) → use POST /api/search and POST /api/agent-book. This is PFS — Programmatic Flight Search powered by the letsfg.co engine, free for 90 days per token. See letsfg.co/for-agents for the full guide.

When you’re ready to integrate it into your own agent, keep reading.

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Pricing

CLI / SDK / MCP / PFS = free search, no LetsFG fee on flight booking. Run letsfg auth once (a zero-amount card setup — nothing is charged) and both searching and booking are free for 90 days. No credits, no unlock step. letsfg book / POST /api/agent-book returns either a confirmed order or a direct airline link — no LetsFG fee either way (you still pay the ticket price itself, plus Stripe’s own processing cut, same as any card charge).

Hotels = 10% now to hold a free-cancellation rate, on every path. That 10% is what pays for flexibility: it books the room today, but the remaining 90% isn’t charged until the hotel’s own cancellation deadline, paid straight to the hotel via a pay_link. Cancel before that deadline and the only cost is the 10% already paid. See Hotels above.

Developer API = prepaid, business use. letsfg.co/developers returns direct airline booking URLs with no per-booking fee. Monthly billing: $0.50/search for the first 10, $0.20 for 11–1,000, then $0.10/search. Resets monthly. Minimum top-up: $5.

💡 Know someone who travels? The more people discover LetsFG, the more airlines we cover — and the better it gets for everyone. ⭐ Star · Share with a friend

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Why developers star this repo

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Get started

Pick where you want search to run. Local runs on your machine for free; PFS and the Developer API run on our servers.

🖥️ CLI / SDK — free, one-time auth

pip install letsfg
letsfg auth          # one-time card-on-file setup → 90-day Bearer token (nothing charged)
letsfg search LHR BCN 2026-06-15

One auth step, then searches are free for 90 days — no install of browsers, no scrapers. The search runs on our servers.

letsfg search LHR JFK 2026-06-15 --cabin C   # cabin class: M economy, W premium, C business, F first
letsfg book off_xxx --passenger '{"given_name":"John","family_name":"Doe","born_on":"1990-01-15","gender":"m","title":"mr"}' --email [email protected]

Booking from CLI search: letsfg book returns either a confirmed order (a real airline PNR, e-ticket to your inbox) or a direct booking link for that exact offer — no LetsFG fee either way. Want direct airline URLs on every search, with no checkout step at all? Use the Developer API below.

🔌 PFS — Programmatic Flight Search (free, server-side)

Run LetsFG’s full search on our servers — no local browser, no install. Access requires a payment method on file: letsfg.co is human-only (Cloudflare Turnstile), so a Bearer token is the only programmatic way in. Nothing is charged to get one — it is a zero-amount Stripe setup — and the token lasts 90 days.

# 1. Request a challenge code
curl -X POST https://letsfg.co/api/agent-access/request

# 2. Add a card at the returned setup_url (nothing is charged), or confirm the
#    SetupIntent yourself against api.stripe.com with the supplied publishable key

# 3. Exchange it → receive a 90-day Bearer token
curl -X POST https://letsfg.co/api/agent-access/verify \
  -H "Content-Type: application/json" \
  -d '{"setup_session_id":"cs_"}'

# 4. Search with the token
curl -X POST https://letsfg.co/api/search \
  -H "Authorization: Bearer " \
  -H "Content-Type: application/json" \
  -d '{"origin":"LHR","destination":"BCN","date_from":"2026-06-15"}'

Search is free; book with POST /api/agent-book — no LetsFG fee either way. Full guide and response schema: letsfg.co/for-agents.

⚡ Developer API — paid, server-side, direct booking URLs

A separate paid product for high-volume commercial integrations; most agents should not use it. Prepaid credits, results in seconds, direct airline booking URLs — plus /discover (20 destinations in one call, 1 credit), async polling, NL query parsing, and a free sandbox.

# Register, then search with your API key
curl -X POST https://letsfg.co/developers/api/v1/agents/register \
  -H "Content-Type: application/json" \
  -d '{"agent_name":"my-agent","email":"[email protected]"}'

curl -X POST https://letsfg.co/developers/api/v1/flights/search \
  -H "X-API-Key: trav_..." \
  -H "Content-Type: application/json" \
  -d '{"origin":"LHR","destination":"BCN","date_from":"2026-06-15"}'

Pricing: $0.50/search for the first 10 each month, $0.20 for 11–1,000, $0.10 beyond. Minimum top-up $5. Test for free in the sandbox first. Full docs: letsfg.co/developers/api/docs.

💡 Like what you see? Support us — ⭐ Star · Share with a friend

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Works everywhere your agent runs

MCP Server (Claude Desktop / Cursor / Windsurf / OpenClaw)

{
  "mcpServers": {
    "letsfg": {
      "command": "npx",
      "args": ["-y", "letsfg-mcp"]
    }
  }
}

Run letsfg auth inside the MCP session once (a zero-amount card setup — nothing is charged — then saves the 90-day Bearer token). After that, search and booking both work immediately, with no LetsFG fee either way.

5-minute quickstarts: Claude Desktop · Cursor · Windsurf

Python SDK

from letsfg import LetsFG

bt = LetsFG()  # reads LETSFG_API_KEY from env
flights = bt.search("LHR", "JFK", "2026-04-15")
print(f"{flights.total_results} offers, cheapest: {flights.cheapest.summary()}")

JavaScript SDK

import { LetsFG } from 'letsfg';

const bt = new LetsFG({ apiKey: 'trav_...' });
const flights = await bt.search('LHR', 'JFK', '2026-04-15');
console.log(`${flights.totalResults} offers`);

Python SDK (cloud search)

from letsfg.local import search_local

# Reads LETSFG_BEARER_TOKEN env var or ~/.letsfg/config.json (set by `letsfg auth`)
result = await search_local("GDN", "BCN", "2026-06-15")

for offer in result.offers[:5]:
    print(f"{offer.airlines[0]}: {offer.currency} {offer.price}")

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Install

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CLI Commands

All commands accept --json for structured output and --api-key to override the env variable.

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How it works

CLI / SDK / MCP (free, cloud-backed)

letsfg auth (once) → Bearer token (90-day) → Search (free) → Book via letsfg.co (no LetsFG fee)

1. Auth — letsfg auth runs the payment-token flow: POST /api/agent-access/request → add a card at the printed setup_url (or confirm the SetupIntent headlessly) → POST /api/agent-access/verify. Nothing is charged. Token saved to ~/.letsfg/config.json, valid 90 days.
2. Search — letsfg search LHR BCN 2026-06-15 calls POST https://letsfg.co/api/search, polls until done (60–90 s), and applies the open-source ranking algorithm locally.
3. Book — POST /api/agent-book. Returns either a confirmed order or a direct booking link for that exact offer. No LetsFG fee either way.

PFS — raw API (same as CLI, without the wrapper)

Payment method on file -> Bearer token (90-day) -> POST /api/search -> poll GET /api/results/ -> POST /api/agent-book

1. Get a Bearer token — POST /api/agent-access/request → present a payment method (hosted card page, headless SetupIntent, or MPP) → POST /api/agent-access/verify. Nothing is charged on the card lanes. Token valid 90 days.
2. Search — POST https://letsfg.co/api/search with Authorization: Bearer . Returns { search_id }. Poll GET /api/results/ every 10 s until status: "done".
3. Book — POST /api/agent-book. No LetsFG fee.

Developer API — paid, direct booking URLs

Register → Fund balance → Discover or Search (credits) → Direct booking URL (no checkout)

1. Discover — POST /flights/discover with up to 20 destinations, get indicative prices sorted cheapest-first. 1 credit, 2–5 s. Use to rank options before committing to a full search.
2. Full search — POST /flights/search (blocking) or /flights/search/async (non-blocking + poll). 1 credit, 60–90 s.
3. Book — each offer includes a direct airline booking_url. No LetsFG fee, no checkout step.

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Architecture

CLI / SDK / MCP / PFS

CLI / SDK / MCP / AI Agent
        │  Payment method on file -> 90-day Bearer token
        ▼
POST letsfg.co/api/search  (bot-protected, token required)
        │
        ▼
letsfg.co server-side search engine
        │
        ▼
GET /api/results/  (poll every 10 s until done)
        │
        ▼
Ranking applied locally (sdk/js/src/ranking.ts, open-source)
        │
        ▼
Results + booking via POST /api/agent-book — no LetsFG fee either way

Developer API

Product / Team / Agent
        │  API key + prepaid credits
        ▼
letsfg.co/developers/api/v1
  ├─ /flights/discover      (indicative prices, 20 dest, 1 credit, 2–5 s)
  ├─ /flights/search        (full search, 1 credit, 60–90 s)
  ├─ /flights/search/async  (non-blocking + poll)
  ├─ /flights/parse-query   (Gemini NL parsing, free)
  └─ /sandbox/flights/*     (fake data, same schema, free)
        │
        ▼
Direct airline booking_url - no checkout step

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Star History

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