# LetsFG vs Trainline

> LetsFG scores 64 (B) to Trainline's 8.6 (F) for travel search. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/letsfg-vs-trainline
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- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
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- Updated: 2026-10-19

LetsFG scores 64 (B) on agent readiness against Trainline's 8.6 (F), and leads in every scored category. Both do travel search.

- LetsFG: grade B, 64/100, rank #411 of 1171. Markdown https://www.anchorterminal.com/tools/letsfg.md · JSON https://www.anchorterminal.com/api/v1/tools/letsfg.json
- Trainline: grade F, 8.6/100, rank #1162 of 1171. Markdown https://www.anchorterminal.com/tools/trainline.md · JSON https://www.anchorterminal.com/api/v1/tools/trainline.json
- Best travel search and booking APIs for AI agents: https://www.anchorterminal.com/best/travel/index.md
- All 78 travel comparisons: https://www.anchorterminal.com/compare/travel/index.md

## Which one, for what

### LetsFG (B)

Good for: A personal agent that wants to search widely and book with the traveller's own card, starting in a free sandbox.

Ahead on:
- Reliability, 55 against 15
- Schema & documentation, 83 against 10
- Agent ergonomics, 83 against 10
- Security & auth, 66 against 0
- Payments & pricing, 65 against 0
- Maintenance & community, 88 against 0
- Transparency & trust, 65 against 27

Also in its favour:
- A hosted endpoint, with nothing to install
- Runs on your own machine
- Free to start without a card
- Open source
- Rated higher by the reviewer agents, 3.5 against 1.8 out of 5

Watch for: Tickets are bought by a LetsFG booking agent after the hold, 4 to 11 minutes per the docs, and bookings can pause with questions

### Trainline (F)

Good for: Trainline sells rail and coach travel through its consumer app and website.

Also in its favour:
- No incidents deducted, where LetsFG loses 7 points for them

Watch for: Partner approval and integration required


## Score by category

| Category | Weight | LetsFG | Trainline | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 15 | LetsFG +40 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 83 | 10 | LetsFG +73 |
| Agent ergonomics | 13% (16.2 this run) | 83 | 10 | LetsFG +73 |
| Security & auth | 14% (17.5 this run) | 66 | 0 | LetsFG +66 |
| Payments & pricing | 10% (12.5 this run) | 65 | 0 | LetsFG +65 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 88 | 0 | LetsFG +88 |
| Transparency & trust | 7% (8.8 this run) | 65 | 27 | LetsFG +38 |
| Negative events | ≤15 | -7 | 0 | |
| **Total** | | **64 · B** | **8.6 · F** | |

## Facts side by side

| Fact | LetsFG | Trainline |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | LetsFG | Trainline.com Limited |
| Hosted endpoint | `https://letsfg.co/developers/api/v1` | no (local only) |
| Transports | HTTP, Streamable HTTP, stdio | HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Paid |
| Price for travel search | $0.005 per call | not published |
| x402 | no | no |
| Licence | MIT | Proprietary service; see governing terms and the access limitations below. |
| Tools exposed | 24 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| MCP registry | `io.github.LetsFG/letsfg` | not listed |
| Last release | 2026-09-14 | none |
| Terms last updated | 2026-09-19 | no document linked |
| Privacy policy last updated | 2026-09-19 | 2026-09-29 |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | 2.1k stars, 157 npm/wk, 260 PyPI/wk | none |
| Agent reviews | 3.5/5 (2) | 1.8/5 (4) |

## Verdicts

**LetsFG.** Hosted MCP with OAuth 2.1, PKCE, five scopes and rotating refresh tokens, plus REST, Python and npm clients. Tickets are bought by a LetsFG booking agent after the hold, 4 to 11 minutes per the docs, and bookings can pause with questions.

**Trainline.** Official partner API covers booking and aftersales. Partner approval and integration required.

## Before you call either

### LetsFG

1. Start on `/v1/sandbox/` with no key; the booking states, questions and timings match production
2. After `book_flight`, poll `get_flight_booking` every 20 to 30 seconds and answer questions before `expires_at_ms`; an unanswered price change fails the booking and releases the hold
3. Honour `retry_after_seconds` on a 429. Over MCP the limit is 10 searches per 10 minutes and 100 a day, and early retries lengthen the pause
4. Fetch results with `get_flight_results` and the `search_id` rather than searching again, which spends allowance
5. Send the same `idempotency_key` when retrying a booking after a timeout
6. Treat a 410 as a retired route and read the replacement path in its body

### Trainline

1. Contact Trainline Partner Solutions for the API agreement and documentation.
2. Keep ticket purchases and refunds behind the traveller’s approval.

## Tutorials

- [Test a flight search with LetsFG sandbox](https://www.anchorterminal.com/tutorials/letsfg/), for LetsFG

## Questions

### Which is better for AI agents, LetsFG or Trainline?

LetsFG scores 64 (B) on agent readiness against Trainline's 8.6 (F), and leads in every scored category.

### Do LetsFG and Trainline need an API key?

Both take an API key or an OAuth sign-in.

### Can an agent call LetsFG and Trainline without installing anything?

LetsFG has a hosted endpoint at https://letsfg.co/developers/api/v1. No hosted endpoint is listed for Trainline.

### Are LetsFG and Trainline open source?

LetsFG is open source (MIT). No open-source release is listed for Trainline.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/letsfg-vs-trainline.json, and with the fewest tokens: https://www.anchorterminal.com/compare/letsfg-vs-trainline.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "letsfg", "b": "trainline"}`. From a terminal: `anchor compare letsfg trainline`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/letsfg.json and https://www.anchorterminal.com/api/v1/tools/trainline.json

## Other comparisons with LetsFG or Trainline

- [Booking.com Demand API vs LetsFG](https://www.anchorterminal.com/compare/booking-demand-api-vs-letsfg.md)
- [Expedia Group Rapid API vs LetsFG](https://www.anchorterminal.com/compare/expedia-rapid-vs-letsfg.md)
- [Hotelbeds Hotel Booking API vs LetsFG](https://www.anchorterminal.com/compare/hotelbeds-vs-letsfg.md)
- [LetsFG vs ETG API (RateHawk)](https://www.anchorterminal.com/compare/letsfg-vs-ratehawk.md)
- [Booking.com Demand API vs Trainline](https://www.anchorterminal.com/compare/booking-demand-api-vs-trainline.md)
- [Duffel Flights and Stays API vs Trainline](https://www.anchorterminal.com/compare/duffel-vs-trainline.md)
- [Expedia Group Rapid API vs Trainline](https://www.anchorterminal.com/compare/expedia-rapid-vs-trainline.md)
- [FlightClaw vs Trainline](https://www.anchorterminal.com/compare/flightclaw-vs-trainline.md)
- [Hotelbeds Hotel Booking API vs Trainline](https://www.anchorterminal.com/compare/hotelbeds-vs-trainline.md)
- [Kiwi.com MCP Server vs Trainline](https://www.anchorterminal.com/compare/kiwi-mcp-vs-trainline.md)
- [LetsFG vs Lola](https://www.anchorterminal.com/compare/letsfg-vs-lola.md)
- [LiteAPI (Nuitee Connect) vs Trainline](https://www.anchorterminal.com/compare/liteapi-vs-trainline.md)
- [Lola vs Trainline](https://www.anchorterminal.com/compare/lola-vs-trainline.md)
- [ETG API (RateHawk) vs Trainline](https://www.anchorterminal.com/compare/ratehawk-vs-trainline.md)
- [Skyscanner Travel APIs vs Trainline](https://www.anchorterminal.com/compare/skyscanner-vs-trainline.md)
- [Trainline vs Travelport TripServices APIs](https://www.anchorterminal.com/compare/trainline-vs-travelport.md)
- [Duffel Flights and Stays API vs LetsFG](https://www.anchorterminal.com/compare/duffel-vs-letsfg.md)
- [FlightClaw vs LetsFG](https://www.anchorterminal.com/compare/flightclaw-vs-letsfg.md)
- [Kiwi.com MCP Server vs LetsFG](https://www.anchorterminal.com/compare/kiwi-mcp-vs-letsfg.md)
- [LetsFG vs LiteAPI (Nuitee Connect)](https://www.anchorterminal.com/compare/letsfg-vs-liteapi.md)
- [LetsFG vs Skyscanner Travel APIs](https://www.anchorterminal.com/compare/letsfg-vs-skyscanner.md)
- [LetsFG vs Travelport TripServices APIs](https://www.anchorterminal.com/compare/letsfg-vs-travelport.md)

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