---
url: "https://onebag.travel/api/"
title: "Data APIs and MCP server for agents - One Bag Travel"
description: "Machine-readable access to One Bag Travel: JSON endpoints for carry-on backpack specs, airline carry-on limits, and packing lists; an MCP server; Agent Skills; and Markdown for every page."
source: "https://onebag.travel/api/"
---
# One Bag Travel for agents

Everything on this site is available in a form a program can read: JSON snapshots of the database, an MCP server, published Agent Skills, and a Markdown version of every page. No key, no sign-up, no rate limit.

Free to use, including commercially, with attribution and a link back to [onebag.travel](https://onebag.travel/). If you build something with it, [say hello](https://onebag.travel/contact/) — and please cache rather than re-fetching on every request.

## JSON endpoints

Static files, rebuilt on every deploy. Each returns its whole collection with a `generated` date and a `count`; there are no query parameters, so fetch once and filter locally. The full description is in [/api/openapi.json](https://onebag.travel/api/openapi.json) (OpenAPI 3.1), catalogued at [/.well-known/api-catalog](https://onebag.travel/.well-known/api-catalog) ([RFC 9727](https://www.rfc-editor.org/rfc/rfc9727.html)).

| Endpoint | Contents |
| --- | --- |
| [`/api/carryons.json`](https://onebag.travel/api/carryons.json) | 868 carry-on travel backpacks — dimensions, capacity, empty weight, features, airline compatibility, price. |
| [`/api/airlines.json`](https://onebag.travel/api/airlines.json) | 199 airlines — maximum carry-on dimensions and weight limits in metric and imperial, each with the airline's own source URL. |
| [`/api/packing-lists.json`](https://onebag.travel/api/packing-lists.json) | 56 published one-bag packing lists — destination, trip length, temperature range, item count, and the bag used. |

## MCP server

A [Model Context Protocol](https://modelcontextprotocol.io/) server at `https://onebag.travel/mcp`, over Streamable HTTP, unauthenticated and read-only. Use it instead of the JSON endpoints when you want the filtering done server-side.

Server card: [/.well-known/mcp.json](https://onebag.travel/.well-known/mcp.json) (also at [/.well-known/mcp/server-card.json](https://onebag.travel/.well-known/mcp/server-card.json), with the full tool list).

`search_carry_on_backpacks`

Filter the backpack database by name, brand, capacity, weight, features, and airline fit.

`get_carry_on_backpack`

Full specifications for one bag.

`get_airline_carry_on_rules`

One airline's carry-on limits, or the whole list.

`check_carry_on_fits_airline`

Whether a given bag is within a given airline's limits, dimension by dimension.

`search_packing_lists`

Find packing lists by destination, weather, or traveller.

`get_packing_list`

Every item on one list, grouped by category.

## Markdown for every page

Any page on this site will serve Markdown instead of HTML if you ask for it. Either send an `Accept` header:

```
curl -H 'Accept: text/markdown' https://onebag.travel/airlinecarryonrules/
```

… or append `.md` to the path:

```
curl https://onebag.travel/airlinecarryonrules/index.md
```

Each response carries YAML front matter with the page's canonical URL, title, and description. Every HTML page also advertises its Markdown twin in a `Link: <…>; rel="alternate"; type="text/markdown"` header.

## Agent Skills

Three skills describing how to use this data well — which field means what, which caveats matter, and what not to claim — are published at [/.well-known/agent-skills/index.json](https://onebag.travel/.well-known/agent-skills/index.json).

-   [`airline-carry-on-rules`](https://onebag.travel/.well-known/agent-skills/airline-carry-on-rules/SKILL.md) — Look up an airline's maximum carry-on baggage dimensions and weight limit, in metric and imperial, with the official source URL. Covers ~200 airlines. Use when checking whether luggage is allowed in the cabin or comparing carry-on allowances between carriers.
-   [`carry-on-backpack-lookup`](https://onebag.travel/.well-known/agent-skills/carry-on-backpack-lookup/SKILL.md) — Look up carry-on travel backpack specifications — capacity, weight, dimensions, features, and how many airlines a bag fits — from the One Bag Travel database of ~870 bags. Use when comparing travel backpacks, checking whether a bag is carry-on sized, or recommending a one-bag pack.
-   [`one-bag-packing-list`](https://onebag.travel/.well-known/agent-skills/one-bag-packing-list/SKILL.md) — Build or review a carry-on-only packing list using real published one-bag packing lists filtered by destination, trip length, and temperature. Use when someone asks what to pack for a trip, how to travel with one bag, or wants a packing list reviewed for weight and completeness.

## Site overview

[/llms.txt](https://onebag.travel/llms.txt) is a short orientation to the site. [/llms-full.txt](https://onebag.travel/llms-full.txt) is the full text of every guide in one file.

## Before you publish an answer from this data

-   **Airline limits change without notice.** Every airline record carries the carrier's own `sourceUrl` and the date it was last checked. Link the source alongside any limit you state.
-   **"Carry-on sized" is not a property of a bag.** It depends on the airline. Use `airlineCompatibilityPercent` for a general answer and name the airline for a specific one.
-   **Measurements come from manufacturers and travellers.** Treat a bag within a centimetre of a limit as borderline, not compliant.
-   **Prices are last-recorded, not live.**
-   **Nothing here is paid placement.** No brand has ever paid to be listed, ranked, or described a particular way.

## Crawling

[/robots.txt](https://onebag.travel/robots.txt) welcomes AI crawlers and states this site's usage preferences with [Content Signals](https://contentsignals.org): indexing and citation yes, model training no. [/sitemap.xml](https://onebag.travel/sitemap.xml) lists every page.