letsfg

# LetsFG

Agent-native flight search and booking. 180+ airline connectors, zero markup,
$20–50 cheaper than travel websites.

**Three-step flow:** Search (free) → Unlock (free) → Book (ticket price only)

## Why Use This

- **180+ airlines in parallel** — Ryanair, EasyJet, Wizz Air, Southwest, AirAsia, Norwegian, Qantas, LATAM, Spirit, Frontier, IndiGo, VietJet, and 170+ more
- **Zero price bias** — no demand inflation, no cookie tracking, no surge pricing. Raw airline prices every time
- **One tool call** — replaces thousands of tokens of browser automation, scraping, and HTML parsing
- **Structured JSON** — prices, times, durations, stops, conditions, airline names

## Setup

### Option A: MCP Server (Recommended for Claude Desktop / Cursor / VS Code)

**Remote (no install):**

```json
{
  "mcpServers": {
    "letsfg": {
      "url": "https://letsfg.co/developers/api/mcp",
      "headers": {
        "X-API-Key": "trav_your_api_key"
      }
    }
  }
}
```

**Local (stdio):**

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

### Option B: CLI

```bash
pip install letsfg
letsfg search LHR BCN 2026-06-15
```

### Option C: Python SDK

```python
from letsfg import LetsFG
bt = LetsFG(api_key="trav_...")
flights = bt.search("LHR", "JFK", "2026-04-15")
```

### Get an API Key (Free)

```bash
letsfg register --name my-agent --email agent@example.com
```

Then attach a payment method (required before unlock):

```bash
letsfg setup-payment --token tok_visa
```

## Workflow

### 1. Resolve Locations First

City names are ambiguous — "London" = LHR, LGW, STN, LCY, LTN. Always resolve first:

```bash
letsfg locations "London"
# LON  London (all airports)
# LHR  Heathrow
# LGW  Gatwick
# ...
```

```python
locations = bt.resolve_location("London")
# Use city code "LON" for all airports, or specific airport "LHR"
```

### 2. Search (FREE, Unlimited)

```python
flights = bt.search("LON", "BCN", "2026-04-01")
# Round trip:
flights = bt.search("LON", "BCN", "2026-04-01", return_date="2026-04-08")
# Multi-passenger:
flights = bt.search("LHR", "SIN", "2026-06-01", adults=2, children=1, cabin_class="C")
```

```bash
letsfg search LON BCN 2026-04-01 --return 2026-04-08 --sort price --json
```

Search returns structured offers:

```json
{
  "passenger_ids": ["pas_0"],
  "total_results": 47,
  "offers": [{
    "id": "off_xxx",
    "price": 89.50,
    "currency": "EUR",
    "airlines": ["Ryanair"],
    "route": "STN → BCN",
    "duration_seconds": 7800,
    "stopovers": 0,
    "conditions": {
      "refund_before_departure": "not_allowed",
      "change_before_departure": "allowed_with_fee"
    }
  }]
}
```

### 3. Unlock (1% of ticket, min $3)

Confirms live price with airline and reveals the direct booking URL. Locks offer for 30 minutes. Charged to your card (or paid via MPP crypto); free on the prepaid Developer API.

```python
unlocked = bt.unlock(flights.cheapest.id)
print(f"Confirmed: {unlocked.confirmed_price} {unlocked.confirmed_currency}")
print(f"Booking URL: {unlocked.booking_url}")
print(f"Expires: {unlocked.offer_expires_at}")
```

```bash
letsfg unlock off_xxx
```

**Note:** Confirmed price may differ from search price (airline prices change in real-time). Inform the user if price changed significantly.

### 4. Book (Ticket Price Only)

```python
booking = bt.book(
    offer_id=unlocked.offer_id,
    passengers=[{
        "id": flights.passenger_ids[0],
        "given_name": "John",
        "family_name": "Doe",
        "born_on": "1990-01-15",
        "gender": "m",
        "title": "mr",
        "email": "john@example.com"
    }],
    contact_email="john@example.com",
    idempotency_key="unique-booking-key-123"
)
print(f"Booked! PNR: {booking.booking_reference}")
```

## Critical Rules

1. **Use REAL passenger details** — airlines send e-tickets to the contact email. Names must match passport/ID exactly. Never use placeholder or fake data.
2. **Always provide `idempotency_key` when booking** — prevents duplicate reservations if the agent retries on timeout.
3. **Resolve locations before searching** — "New York" = JFK, LGA, EWR, NYC. Use `resolve_location()` first.
4. **Search is free** — search as many routes, dates, and cabin classes as needed.
5. **Map passenger IDs** — search returns `passenger_ids`. Each booking passenger must include the correct `id`.

## Best Practices

### Search Wide, Unlock Narrow

```python
# Compare multiple dates (all FREE)
dates = ["2026-04-01", "2026-04-02", "2026-04-03"]
best = None
for date in dates:
    result = bt.search("LON", "BCN", date)
    if result.offers and (best is None or result.cheapest.price < best[1].price):
        best = (date, result.cheapest)

# Only unlock the winner
unlocked = bt.unlock(best[1].id)
```

### Filter Before Unlocking

```python
flights = bt.search("LHR", "JFK", "2026-06-01", limit=50)

candidates = [
    o for o in flights.offers
    if o.outbound.stopovers == 0
    and o.outbound.total_duration_seconds < 10 * 3600
]

if candidates:
    best = min(candidates, key=lambda o: o.price)
    unlocked = bt.unlock(best.id)
```

## Error Handling

| Error | Category | Action |
|-------|----------|--------|
| `SUPPLIER_TIMEOUT` (504) | Transient | Retry after 1-5s |
| `RATE_LIMITED` (429) | Transient | Wait and retry |
| `INVALID_IATA` (422) | Validation | Use `resolve_location()` to fix |
| `OFFER_EXPIRED` (410) | Business | Search again for fresh offers |
| `PAYMENT_REQUIRED` (402) | Business | Attach a card: `letsfg setup-payment` (or pay via MPP on the 402 challenge) |
| `FARE_CHANGED` (409) | Business | Re-unlock to get current price |

```python
from letsfg import LetsFG, OfferExpiredError, PaymentRequiredError

try:
    unlocked = bt.unlock(offer_id)
except OfferExpiredError:
    # Airline sold the seats — search again
    flights = bt.search(origin, dest, date)
except PaymentRequiredError