The API Report CardAPI Index
Gray Line

Gray Line API

Sightseeing Tours & Activities (Tour Operator Network) · grayline.com

Gray Line integrates partners through the TourCMS Marketplace API: RESTful, XML-only, with HMAC-SHA256 signed requests. Sandbox work is self-serve against test operator 3930; production access goes through Gray Line Connect. Official PHP, Ruby, .NET, and Python libraries exist.

Last verified: July 2026Hospitality & Travel
API GRADE
B+
VERIFIED JUL 2026

SCORECARD

ExistenceGOODNo first-party portal; distribution runs on the documented TourCMS Marketplace API, RESTful and XML-only.
AccessGOODSelf-serve start via a TourCMS agent trial and test operator 3930, then production through Gray Line Connect.
CoverageGOODDestination search, tour detail, real-time availability, booking start and commit, promo codes, and a rate-limit status call.
AuthGOODHMAC-SHA256 signed headers are fiddly to hand-roll; official client libraries in four languages wrap the scheme.
Docs & DXGOODTourCMS publishes full API docs and PHP, Ruby, .NET, and Python libraries; operator guidance sits in a separate Zendesk.
StabilityGOOD
Supergood: Gray Line shipped a real API. Most vendors don't; we ship near-native APIs for the rest.

Frequently asked questions

Gray Line scores B+ on the API Report Card. Gray Line integrates partners through the TourCMS Marketplace API: RESTful, XML-only, with HMAC-SHA256 signed requests. Sandbox work is self-serve against test operator 3930; production access goes through Gray Line Connect. Official PHP, Ruby, .NET, and Python libraries exist.

Tried to integrate with Gray Line?
SOURCES
Capterra reviewers note the TourCMS partner/admin UI 'feels as if it wasn't refreshed for the last 10 years', friction during integration QA and partner onboarding capterra.com
Availability inconsistencies reported by some operators/integrators (cached availability lagging live inventory) capterra.com
Documentation is split between tourcms.com/support/api (developer-facing) and support.tourcms.com Zendesk articles (operator/licensee-facing), with separate gated sections specifically for 'Gray Line Licensees', non-licensee integrators have to piece together the full picture support.tourcms.com
XML-only response format (no JSON) is increasingly out of step with modern T&A APIs (Bokun, Rezdy, FareHarbor all offer JSON/REST) and forces extra parsing work tourcms.com
HMAC-SHA256 signature scheme with per-request timestamp + path string is error-prone to implement from scratch; TourCMS effectively pushes partners toward their official client libraries tourcms.com
Persistent customer-service and refund complaints on Trustpilot (cancellation handling, double-charges, no-show disputes) trustpilot.com
Quality varies wildly by licensee, Gray Line is a franchise/licensee network, so the brand inherits operational complaints from each local operator rather than enforcing a single SLA community.ricksteves.com
TripAdvisor reviews of individual Gray Line operators (e.g., Denver) flag inconsistent guides and itinerary changes tripadvisor.com
Feefo public review stream shows mixed feedback across global locations, often around vehicle condition and timing feefo.com