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 https://letsfg.co/for-agents.

⚠️ 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 https://letsfg.co/for-agents.

We're LetsFG — a community of travelers.

Planning a trip shouldn't mean 47 tabs open, 3 hours of searching, and that feeling you could've got a better deal if you'd just waited a little longer. Then a separate app to watch for delays. Then another one for the ride to the airport.

So we're building one thing that handles all of it. The real best deal, across every airline and OTA. The right airport when your city has three. Ground transport on the other end. Someone watching your flight so a delay or cancellation gets handled before you're the one stuck in a line.

No markup. No tracking. No price that goes up because you looked twice.

Search and booking work today, right here in this repo. The rest is what we're building next.

     

     

Join the community. Help others find cheaper flights. Spread the word.⭐ Star the repo. Share with a friend ✈️

         

Flights are step one. Here's the part that's live.

Hundreds of airlines. Real prices. One function call.

LetsFG gives your AI agent flight search and booking superpowers. Our server-side engine scans the entire world for the cheapest price. Search is free. Real airline tickets, booked through us or handed to you as a direct link.

The same flight costs $20–$50 less because you skip OTA inflation, cookie tracking, and surge pricing.

CLI or scripts: Run letsfg auth once — it puts a payment method on file through a zero-amount Stripe setup (nothing is charged) and returns a 90-day token. Then letsfg search and letsfg book hit our cloud engine. Developer API: a separate paid product for high-volume commercial use; most agents do not need it. → Get started

Supporters

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 <credential>

  3. POST https://letsfg.co/api/agent-access/verify → receive your Bearer token

  4. Search: POST https://letsfg.co/api/search with Authorization: Bearer <token>

  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.

Related MCP server: Flights MCP

Real prices: LetsFG vs Google Flights

We searched 5 routes on Google Flights and LetsFG on the same day (June 15, 2026). Same airline, same itinerary — LetsFG was cheaper every time:

$116 cheaper across 6 routes in a verified comparison (May 2026). 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.

Try it right now — no install needed

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

🌐 Search on letsfg.co

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.

Pricing

CLI / SDK / MCP = free search. Run letsfg auth once (a zero-amount card setup — nothing is charged) and searches are free for 90 days. No credits, no Playwright. Booking goes through POST /api/agent-book.

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.

PFS (raw API) = same as CLI but you call the API directly. Get a 90-day Bearer token by putting a payment method on file, then call POST /api/search and POST /api/agent-book yourself. Purpose-built for agents (OpenClaw, Claude, GPT, etc.) that call the API directly.

💡 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

Why developers star this repo

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

Booking from CLI search: you get a letsfg.co booking link, not a direct airline URL. Unlock it through the letsfg.co concierge checkout (1% fee, min $3) to reveal the airline link. Want direct airline URLs with no fee? 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_<from step 1>"}'

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

Search is free; booking links go through letsfg.co (1% fee, min $3). 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":"you@example.com"}'

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.

# Search (free with letsfg auth token)
letsfg search LON BCN 2026-04-01 --return 2026-04-08 --sort price

# Unlock (confirms live price, holds for 30 min — 1% fee, min $3)
letsfg unlock off_xxx

# Book
letsfg book off_xxx \
  --passenger '{"id":"pas_0","given_name":"John","family_name":"Doe","born_on":"1990-01-15","gender":"m","title":"mr"}' \
  --email john.doe@example.com

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

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 (prints the tweet to post, then saves the token). After that, searches work immediately.

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

Get a key: letsfg register --name my-agent --email you@example.com

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}")

Install

CLI Commands

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

How it works

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

letsfg auth (once) → Bearer token (90-day) → Search (free) → Unlock & Book via letsfg.co

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/<id> -> 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 <token>. Returns { search_id }. Poll GET /api/results/<search_id> 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.

The server-side engine builds cross-airline round-trips by combining one-way fares from different carriers. A Ryanair outbound + Wizz Air return can save 30-50% vs booking a round-trip on either airline alone.

Search a city code and LetsFG automatically searches all airports in that city. LON expands to LHR, LGW, STN, LTN, SEN, LCY. NYC expands to JFK, EWR, LGA. Works for 25+ major cities worldwide.

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/<search_id>  (poll every 10 s until done)
        │
        ▼
Ranking applied locally (sdk/js/src/ranking.ts, open-source)
        │
        ▼
Results + booking links via letsfg.co (1% fee)

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

Star History

letsfg.co · API Docs · Connector Health · PyPI · npm · Smithery · Instagram · TikTok · X

Open source · MIT License · Made with ❤️ by travelers, for travelers

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