What you can do

The same SDK release works against every STX exchange. Exchanges do not all offer the same features yet, so the SDK asks each one what it has, and a call that needs a missing feature raises STXNotAvailableError instead of an obscure HTTP error. Nothing else on the client changes.

Every capability, and the calls for it

You want to	Calls	Feature
Read markets and events	markets(), iter_markets(), market(), events(), iter_events()	always
Place, cancel and read orders	place_order(), place_orders(), cancel_order(), cancel_orders(), cancel_all_orders(), orders(), order()	always
Read your account	me(), balance(), positions(), fills(), settlements(), deposits(), withdrawals(), fees(), account_market_stats()	always
Stream market data	ws.orderbook(), ws.ticker(), ws.trades(), ws.markets(), ws.market_stats(), ws.market_updates(), ws.market()	always
Stream your account	ws.orders(), ws.fills(), ws.positions(), ws.balances(), ws.settlements(), ws.account_view()	always
Combos (player and maker)	ws.rfq(), ws.combo_quote(). See Combos	combos
Connect members to your app	oauth.OAuthClient.discover(), begin_authorization(), complete_authorization(), member_client(), unlink(). See Apps: connect members	oauth.member
Act as your app (catalog and market data)	app_client(), client_credentials(). See App tokens and market data	oauth.app
Sign members in with STX	oauth.Connect: start(), finish(). See Sign in with STX	connect
Send members to accept new terms on STX	STXTermsRequiredException.terms_url, oauth.terms_url_with_return()	terms.stx_page
Create markets	create_markets() with an app token. See Create markets	markets.create
List market types	market_types()	market_types
Read an event’s players and stats	event_players(), stats_for()	event_players
Leaderboard and public profile	leaderboard(), leaderboard_me(), update_profile()	leaderboard

Which exchange offers what

Probed with capabilities() on 20 October 2026. Use the call yourself for the exchange you are on: exchanges gain features with each release.

Feature	US demo	Ontario demo	Ontario production
oauth	yes	no	no
oauth.member	yes	no	no
oauth.app	yes	no	no
connect	yes	no	no
terms.stx_page	yes	no	no
markets.create	yes	no	no
market_types	yes	no	no
event_players	yes	yes	yes
leaderboard	yes	no	no

US demo was on API version 3.3.196, Ontario demo and production on 3.3.186. In Ontario an app will read public market data only and will not act for members.

Ask an exchange

from stx import STX

with STX(region="ontario", env="demo") as client:
    caps = client.capabilities()
    print(caps.host, caps.api_version)
    for feature in caps.features.values():
        print(f"{feature.id:15} {str(feature.available):5}  {feature.how}")

Sample output:

demo.stxapp.ca 3.3.194-5
oauth           False  authorization-server metadata answers 404
oauth.member    False  no OAuth on this exchange
oauth.app       False  no OAuth on this exchange
connect         False  no OAuth on this exchange
terms.stx_page  False  no OAuth on this exchange
markets.create  False  no OAuth on this exchange
market_types    False  GET /api/v1/types answers 404 not_found
event_players   True   GET /api/v1/events/00000000-0000-0000-0000-000000000000/players answers 404 'event not found' (route exists)
leaderboard     False  GET /api/v1/leaderboard?limit=1 answers 404 'Leaderboard is not enabled'
combos          True   rfq join answered 'unauthorized' (the channel exists)

capabilities() changes nothing on the exchange: it reads the discovery documents, makes GET requests a missing route answers with a 404, and joins one channel that is refused at once. The answer is cached on the client; capabilities(refresh=True) asks again and probe_channels=False skips the socket. On AsyncSTX it is await client.capabilities().

caps.available("combos") is True only when the exchange showed it has the feature; caps.require("combos") raises STXNotAvailableError when it is known to be absent; caps.to_dict() gives {feature: True | False | None}. None means it could not be decided, for example the authenticated probes on a client with no credentials, or market_types with an app token that lacks the events scope.

Feature	Available when
oauth	/.well-known/oauth-authorization-server answers with the metadata document
oauth.member	the document offers the authorization_code grant and a member scope
oauth.app	the document offers the client_credentials grant
connect	the document lists the openid scope
terms.stx_page	members can connect and terms.write is no longer a scope
markets.create	app tokens are offered and the document lists markets.write
market_types	GET /api/v1/types answers
event_players	GET /api/v1/events/{event_id}/players exists
leaderboard	GET /api/v1/leaderboard answers
combos	the rfq channel exists

What not available looks like

STXNotAvailableError has feature (the id above), host and a message naming both. Captured on Ontario demo:

import stx
from stx import STX, PlayerStatLine, oauth

with STX(region="ontario", env="demo") as client:
    try:
        client.market_types()
    except stx.STXNotAvailableError as exc:
        print(f"{type(exc).__name__}: {exc}  feature={exc.feature!r} host={exc.host!r}")

STXNotAvailableError: Market types are not available on demo.stxapp.ca yet.  feature='market_types' host='demo.stxapp.ca'

The other calls on the same exchange:

create_markets: STXNotAvailableError: Creating markets is not available on demo.stxapp.ca yet.  feature='markets.create' host='demo.stxapp.ca'
leaderboard: STXNotAvailableError: The leaderboard is not available on demo.stxapp.ca yet.  feature='leaderboard' host='demo.stxapp.ca'
OAuthClient.discover: STXNotAvailableError: OAuth is not available on demo.stxapp.ca yet.  feature='oauth' host='demo.stxapp.ca'

STXCombosUnavailableException is an STXNotAvailableError as well as an STXChannelException, so existing handlers keep working. A scope an exchange does not offer is reported the same way, with feature scope:<name>, for example The orders.write scope is not available on demo.stxapp.ca yet. Every not-available error derives from STXException; see Errors & retries.