Engine
Engine (formerly Hotel Engine, rebranded in 2024) is a Denver, Colorado business travel and spend platform for booking and managing lodging, flights, rental cars, group travel, and meeting and event spaces, with travel policy enforcement, trip approvals, consolidated DirectBill invoicing, and the Engine X charge card. Engine says it serves 25,000+ businesses and 1.2 million travelers with negotiated rates across 1,000,000+ hotel properties. Its API product is Omni — a partner-facing lodging inventory API offered over gRPC and HTTP/JSON, authenticated with mutual TLS, that covers property content, real-time rate shopping, booking, folio generation, and cancellation. Omni is protobuf-first: the proto contracts are published under Apache 2.0 on GitHub and the Swagger document, descriptor set, and JVM client bindings are generated from them and released per version.
Engine publishes 4 API contracts indexed on the APIs.io network, including Catalog Service API, Lodging Booking Service API, Lodging Shopping Service API, and 1 more. Tagged areas include Company, Travel, Business Travel, Lodging, and Hotels.
The Engine catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.
Engine’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, pricing, signup flow, and 83 more developer resources.
Kin Score
Markets this provider is in provisional
The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.
| Market | Position | Depth | Registered MCP server | Declares compatibility |
|---|---|---|---|---|
| Travel and Airline Distribution | builds-on | 17.2 (thin) | - | - |
| Buf Schema Registry (public Protocol Buffers modules, gRPC / ConnectRPC schema publishers) | builds-on | 17.2 (thin) | - | - |
Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.
Standards implemented 3
Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.
APIs 4
Individual APIs this provider publishes, each with its own machine-readable definition.
Engine Catalog Service API
The CatalogService API from Engine — 1 operation(s) for catalogservice.
Engine Lodging Booking Service API
The LodgingBookingService API from Engine — 5 operation(s) for lodgingbookingservice.
Engine Lodging Shopping Service API
The LodgingShoppingService API from Engine — 2 operation(s) for lodgingshoppingservice.
Engine Content Service API
The Content Service API from Engine — 2 operation(s) for content service.
Open Collections 4
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Omni, Powered by Engine Catalog Service API
OPEN COLLECTIONOmni, Powered by Engine Content Service API
OPEN COLLECTIONOmni, Powered by Engine Lodging Booking Service API
OPEN COLLECTIONOmni, Powered by Engine Lodging Shopping Service API
OPEN COLLECTIONAgent Skills 4
Packaged agent skills for driving this provider's APIs from an AI assistant.
Manage and cancel Engine lodging bookings
AGENT SKILLSync the Engine lodging property catalog
AGENT SKILLEngine API pricing
Prices published by Engine, read 2026-10-28 from engine.com/pricing.
| Plan | Price |
|---|---|
| Engine | Engine is free. Not a free trial. Actually free. Includes: No membership fees, no contracts, no minimum spend; hotels pay Engine a commission |
Plan details, limits and sources →
Rate limits
- ContentService.ListProperties (burst): 400 requests per minute
- ContentService.ListProperties (sustained): 18000 requests per hour
- LodgingShoppingService.FindBestOffers / FindBestOffersStreaming (burst): 50 requests per minute
Pricing Plans 1
Published pricing tiers and plan structures.
Rate Limits 1
Documented rate limits and quota policies.
Hotel Engine Rate Limits
RATE LIMITSService Levels 1
Uptime the provider promises or reports, as SLA4OAI. Read from its own pages; APIs.io runs no monitors.
Engine
SLAFinOps 1
Cost, billing, and metering signals for API financial operations.
Hotel Engine Finops
FINOPSSemantic Vocabularies 1
JSON-LD contexts and semantic vocabularies used across these APIs.
Hotel Engine Context
JSON-LDSpectral Rules 1
Spectral governance rulesets for linting and validating these APIs.
Engine API Rules
SPECTRALOpenAPI Overlays 1
Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.
JSON Schema 15
Standalone JSON Schema definitions for this provider's data models.
apiHttpBody
JSON SCHEMABook_Lodging_Service_BookRequest_v1
JSON SCHEMABook_Lodging_Service_ConfirmOfferRequest_v1
JSON SCHEMABook_Lodging_Service_ConfirmOfferRequest_v1
JSON SCHEMABook_Lodging_Service_GetBookingsRequest_v1
JSON SCHEMAGetPropertiesRequest_v1
JSON SCHEMAGetPropertiesResponse_v1
JSON SCHEMAListPropertiesResponse_v1
JSON SCHEMAListPropertyCatalogRequest_v1
JSON SCHEMAListPropertyCatalogResponse_v1
JSON SCHEMAScroll for all 15
Security Posture 4
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
Recommended x-agentic-access execution contracts for AI agents.
Resources
Get Started 4
Portal, sign-up, and the first successful call
Documentation 3
Reference material describing how the API behaves
Agent Surfaces 4
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 5
Pagination, idempotency, versioning, errors, and events
Build 5
SDKs, sample code, and the tooling you integrate with
Access & Security 6
Authentication, authorization, and security posture
Operate 6
Status, limits, changes, and where to get help
Commercial 6
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
Other 48
Properties that don't map to a standard resource type
Scroll for all 48
Source (apis.yml)
Engine API — frequently asked questions
Does Engine have an API?
Yes. APIs.io lists 4 APIs from Engine, including Engine Catalog Service API, Engine Lodging Booking Service API and Engine Lodging Shopping Service API, and 1 more.
Is there an OpenAPI specification for the Engine API?
Yes. APIs.io indexes 4 OpenAPI specifications for Engine, each linked for download from this page.
How do I authenticate with the Engine API?
Engine uses bearer-token authentication (mutualTLS · 1 scheme). The details are profiled on APIs.io as Hotel Engine Authentication.
How much does the Engine API cost?
Engine publishes its prices; its Engine plan is Engine is free. Not a free trial. Actually free. as of 2026-10-28. APIs.io lists 1 pricing plan for Engine, with each plan's price, limits and inclusions under Pricing on this page.
Is the Engine API ready for AI agents?
Engine has a Kin Score of 62.9 out of 100 (strong) and an Agent Readiness score of 27.2 (agent-aware), scored by API Evangelist on 2026-11-06.
Work with this as data
Every provider here is available over the APIs.io API and to AI agents over MCP.