Feature Gates

Saturday’s API features progress through launch stages. The stage controls a feature’s visibility, who can reach it, and what stability you can expect from it. Not all API features ship at the same time. When you integrate Saturday, some features are in early access (alpha), some in public beta, and some stable (GA). If an endpoint returns a 404 when you expect it to work, check the feature stage: it may be in STEALTH or require alpha access.

Launch stages

Stage	What happens	Who can access	Stability
STEALTH	Endpoint returns 404 (indistinguishable from nonexistent)	Nobody	Not available
ALPHA	Works for allowlisted partners	Specific partners by invitation	May change without notice
BETA	Works for all authenticated partners	All partners	Breaking changes may occur with 14 days notice
GA	Production-stable	All partners	Stable, backward compatible
DEPRECATED	Still works but being phased out	All partners	Sunset date announced per feature

STEALTH

A stealth feature is invisible. The endpoint returns a 404 byte-identical to a request for a path that doesn’t exist: same body, same headers. The request never reaches authentication, CORS, or request logging, so no timing or header difference distinguishes a gated endpoint from a nonexistent one.

ALPHA

Alpha features are available to partners who have been invited. Reaching an alpha feature without being on the allowlist returns a 403:

{
  "error": {
    "type": "authorization_error",
    "code": "feature_alpha",
    "message": "The products feature is in alpha. Contact api-support@saturday.fit for early access.",
    "documentation_url": "https://docs.saturday.fit/errors#feature_alpha",
    "request_id": "req_a1b2c3d4e5f6"
  }
}

The response carries X-Saturday-Feature-Stage: ALPHA whether or not you are on the allowlist. On the allowlist, it also carries the notice header:

X-Saturday-Feature-Stage: ALPHA
X-Saturday-Alpha-Notice: This feature is in alpha. Behavior may change without notice. Report issues to api-support@saturday.fit.

BETA

Beta features work for all authenticated partners. Responses include:

X-Saturday-Feature-Stage: BETA
X-Saturday-Beta-Notice: This feature is in beta. Breaking changes may occur with 14 days notice. Pin your integration to the current behavior and monitor the changelog.

GA (General Availability)

GA features are production-stable with backward compatibility guarantees. Breaking changes go through a deprecation cycle.

DEPRECATED

Deprecated features still work but will be removed. Responses carry:

X-Saturday-Feature-Stage: DEPRECATED
Deprecation: true

The Deprecation header follows RFC 8594. Sunset dates are announced per feature; ask at api@saturday.fit if a feature you depend on is marked deprecated.

The feature keys

Five keys carry a stage. Each covers the routes listed beside it.

Feature	What it controls	Shipped default
`nutrition`	Fuel/hydration/electrolyte calculation, prep, inference	ALPHA
`products`	Curated product database (186+ products)	ALPHA
`gear`	Gear management CRUD (bottles, flasks)	STEALTH
`ai_coach`	AI coaching with SSE streaming	STEALTH
`ai_data`	AI-generated insights, churn risk, ML bias	STEALTH

The right-hand column is the default the gateway falls back to, not a statement about production. Each environment stores its own stages in configuration, and a per-partner override can raise a single partner above the global stage. Read GET /v1/ for what your key can actually reach today.

Stage changes are made in configuration rather than by deploying, and propagate within 5 minutes.

Feature groups

Features are grouped so a stage transition can move several at once:

Group	Features	Example transition
`core`	nutrition, products	”Move core to BETA” gives all partners nutrition and products
`advanced`	ai_coach, ai_data	”Move advanced to ALPHA” gives selected partners the AI features
`all`	All 5 features	”Move all to GA”

Getting alpha access

Alpha access is by invitation. To request access:

Email api@saturday.fit with your platform name, use case, and expected volume
Saturday reviews the request and adds your partner ID to the alpha allowlist
Within 5 minutes, your API key works on alpha-stage endpoints

Alpha partners get early access to new features before public beta, a direct support channel for integration questions, and a say in API design decisions. There is no additional cost.

Checking feature availability

The API root endpoint shows what your key can reach:

GET /v1/

The response lists the reachable endpoints, marking alpha-stage ones. Features in STEALTH are omitted from discovery, from the error catalog, and from this documentation.

Response headers reference

Header	When sent	Value
`X-Saturday-Feature-Stage`	ALPHA, BETA, DEPRECATED	Stage name
`X-Saturday-Alpha-Notice`	ALPHA (on allowlist)	Stability warning + support contact
`X-Saturday-Beta-Notice`	BETA	Breaking changes warning
`Deprecation`	DEPRECATED	`true` (RFC 8594)

Getting Started

Core Guides

Integration Guides

Coach API

Platform

Feature Gates

Feature Gates

Launch stages

STEALTH

ALPHA

BETA

GA (General Availability)

DEPRECATED

The feature keys

Feature groups

Getting alpha access

Checking feature availability

Response headers reference

​Feature Gates

​Launch stages

​STEALTH

​ALPHA

​BETA

​GA (General Availability)

​DEPRECATED

​The feature keys

​Feature groups

​Getting alpha access

​Checking feature availability

​Response headers reference

Feature Gates

Launch stages

STEALTH

ALPHA

BETA

GA (General Availability)

DEPRECATED

The feature keys

Feature groups

Getting alpha access

Checking feature availability

Response headers reference