axiam-sdk (Python)

Official Python client SDK for AXIAM — Access eXtended Identity and Authorization Management.

Platform documentation: https://ilpanich.github.io/axiam/ — getting started, the authorization model, the OAuth2/OIDC surface, and the operations guides. This README covers the SDK; the site covers the server it talks to.

Package identity

• Repository: github.com/ilpanich/axiam-python-sdk
• PyPI package: axiam-sdk
• Registry: pypi.org/project/axiam-sdk (reserved, not yet published)
• Version tags: vX.Y.Z
• API docs: ilpanich.github.io/axiam-python-sdk
• License: Apache-2.0
• Python: >=3.10 (D-11)

Contract conformance

This SDK conforms to CONTRACT.md §1–§13 and §12.7, §14, §15, §17, §19, §21, §22, §23 (including §6.1 mTLS and the §10.1 minimum local-verification set).

§12.7, §14, §15 and §22 are named rather than folded into the range because they landed after this SDK already claimed §1–§13: widening the range silently would turn a statement that was true when written into a different claim without anyone editing it.

See CONTRACT.md for the full cross-language behavioral contract.

Status

Implemented (Phase 19). AxiamClient (sync) and the dedicated AsyncAxiamClient (async, SDK-Q08) each expose the same canonical operation names — login, verify_mfa, refresh, logout, check_access, can, batch_check, and the nine §12 OIDC/SSO relying-party operations (see below) — as sync or async def methods respectively (never an async_*-prefixed twin on the sync class). Each client owns its own session, cookie jar, and single-flight refresh guard. gRPC (sync grpcio + async grpc.aio), AMQP (async-only aio-pika), a FastAPI dependency plus an oidc_login_router, and a Django middleware plus oidc_login_views, are all available. Seven runnable examples live under examples/.

Installation

pip install axiam-sdk

The FastAPI dependency and Django middleware are optional extras — install only what you need, since a pure REST/gRPC/AMQP consumer should not be forced to pull in FastAPI or Django:

pip install "axiam-sdk[fastapi]"
pip install "axiam-sdk[django]"

[speed] adds uvloop for async workloads — measured at −20% client CPU and a materially tighter p95 on the check_access path. The SDK never installs a loop policy for you; see PERFORMANCE.md, which also explains why a single CPython process tops out around 310 checks/s and what to do about it:

pip install "axiam-sdk[speed]"

from axiam_sdk import AxiamClient

Quickstart

Login + MFA (§1, §5) — sync AxiamClient or async AsyncAxiamClient

AxiamClient (sync) and AsyncAxiamClient (async, SDK-Q08) are separate classes, each with their own session — pick the one that matches your call site's paradigm.

from axiam_sdk import AxiamClient

# tenant_slug is required — AXIAM is multi-tenant and there is no default
# tenant (§5). login/refresh also require organization context (§5.1) — a
# tenant slug is only unique within an org — so pass org_slug too. TLS is
# always verify=True (§6); the only escape hatch is an explicit custom_ca
# parameter, never a boolean bypass.
with AxiamClient(base_url="https://localhost:8443", tenant_slug="acme", org_slug="acme") as client:
    result = client.login(email, password)
    if result.mfa_required:
        result = client.verify_mfa(result.mfa_token, totp_code)
    print(result.session_id, result.expires_in)

import asyncio
from axiam_sdk import AsyncAxiamClient


async def main() -> None:
    async with AsyncAxiamClient(
        base_url="https://localhost:8443", tenant_slug="acme", org_slug="acme"
    ) as client:
        result = await client.login(email, password)
        if result.mfa_required:
            result = await client.verify_mfa(result.mfa_token, totp_code)
        print(result.session_id, result.expires_in)


asyncio.run(main())

See examples/login_mfa.py.

REST authorization checks — check_access / can / batch_check (§1)

result = client.check_access("resource:read", resource_id)
can_write = client.can("resource:write", resource_id)

from axiam_sdk import AccessCheck

results = client.batch_check(
    [
        AccessCheck(action="resource:read", resource_id=resource_id),
        AccessCheck(action="resource:delete", resource_id=resource_id, scope="admin"),
    ]
)

AsyncAxiamClient exposes the same check_access/can/batch_check names as async def methods, each backed by that client's own session and single-flight refresh guard (§9). See examples/rest_authz.py.

gRPC authorization checks (§1, §5, §9, §6)

AuthzGrpcClient (sync, grpcio) and AsyncAuthzGrpcClient (async, grpc.aio) are both first-class transports — the async client is not a thread-pool bridge over the sync one.

from axiam_sdk.grpc import AuthzGrpcClient

client = AuthzGrpcClient(
    "localhost:9443",
    token_fn=lambda: current_access_token,  # non-blocking cache read
    tenant_id=tenant_id,
    refresh_fn=refresh_fn,  # invoked exactly once on UNAUTHENTICATED, then one retry (§9.3)
)
decision = client.check_access(subject_id, "resource:read", resource_id)

See examples/grpc_checkaccess.py.

gRPC-only userinfo — get_user_info (§1.1)

get_user_info is the low-latency gRPC counterpart of the server's REST GET /oauth2/userinfo endpoint (CONTRACT.md §1.1, contract 1.3). It has no REST form in the SDK vocabulary. The request is empty — identity is derived entirely server-side from the bearer token — and it returns a typed UserInfo(sub, tenant_id, org_id, email, preferred_username). email is populated only when the access token carries the email scope and preferred_username only with the profile scope (both None otherwise); sub/tenant_id/org_id are always present. Calling it with no token raises AuthError client-side without a wire call, and a gRPC UNAUTHENTICATED drives the same single-flight refresh-and-retry-once path as check_access (§9). It is exposed as get_user_info() on both AuthzGrpcClient (sync) and AsyncAuthzGrpcClient (async).

info = client.get_user_info()
print(info.sub, info.tenant_id, info.org_id, info.email, info.preferred_username)

AMQP event consumer (§8)

from axiam_sdk.amqp import ErrDrop, consume


async def handler(event: dict) -> None:
    if "action" not in event:
        raise ErrDrop("poison message")  # nack without requeue
    ...  # None return -> ack; any other exception -> nack with requeue


await consume(channel, "axiam.authz.request", signing_key, handler, prefetch=10)

Every delivery's HMAC-SHA256 signature is verified BEFORE the handler is ever invoked — an unverified message never reaches your code. See examples/amqp_consumer.py.

Reactors — AMQP extension actors (§22)

A reactor is an external process that subscribes to named hook events on the AMQP bus and answers back — allow, deny, or a field-allow-listed mutation — inside a timeout the server declared. It is AXIAM's answer to Zitadel Actions and Keycloak SPIs, and the difference is the whole design: those load third-party code into the authorization server, and this keeps it outside, reachable only through a signed reply schema the server validates before it believes a word of it.

from axiam_sdk.amqp import (
    LOGIN_POST_AUTH,
    TOKEN_PRE_ISSUE,
    ReactorConfig,
    ReactorDecision,
    ReactorEvent,
    aio_pika_dialer,
    allow,
    deny,
    mutate,
    reactor_serve,
)


async def decide(event: ReactorEvent) -> ReactorDecision:
    # token.pre_issue is mutable — the `ext.` namespace, and nothing else.
    if event.event == TOKEN_PRE_ISSUE:
        return mutate({"ext.cost_center": "42"})
    # login.post_auth is veto-only, plus step-up.
    if event.event == LOGIN_POST_AUTH and event.payload.get("ip", "").startswith("198.51.100."):
        return deny("embargoed region")
    return allow()


await reactor_serve(
    aio_pika_dialer("amqps://reactor:secret@broker.example.com:5671"),
    ReactorConfig(
        tenant_id="11111111-1111-1111-1111-111111111111",
        reactor_id="99999999-9999-9999-9999-999999999999",
        signing_key=subkey,  # the tenant's HKDF-derived AMQP subkey, never the master key
    ),
    decide,
)

Binding handlers per event (§22.14)

The if chain above is the shape every multi-event reactor grows, and its last line — return allow() — answers on behalf of code that never ran. That is the defect §22.10 rule 2 forbids the runtime from committing, relocated into your file where the rule does not reach it: an operator who set fail_closed on the registration has it defeated there.

ReactorRouter is §22.14's declarative form, in the spirit of the §11 declarative authorization helpers:

from axiam_sdk.amqp import LOGIN_POST_AUTH, TOKEN_PRE_ISSUE, ReactorRouter, reactor_serve

router = ReactorRouter()


@router.on(TOKEN_PRE_ISSUE)
def enrich_token(event: ReactorEvent) -> ReactorDecision:  # sync or async, both work
    return mutate({"ext.cost_center": "42"})


@router.on(LOGIN_POST_AUTH)
async def screen_login(event: ReactorEvent) -> ReactorDecision:
    return deny("embargoed region") if await embargoed(event) else allow()


await reactor_serve(dialer, config, router.handler())

• A misspelled event is refused when you bind it — ReactorRouter accepts only §22.5 registry names, which is also how it refuses the three hot-path operations §22.7 excludes: they are in no registry row.
• An unbound event abstains — no reply, and the registration's failure_policy decides (§22.8), exactly as it decides a timeout. Never a synthesized allow.
• A duplicate binding raises rather than silently overwriting, and router.events feeds default_failure_policy_for so you can see what an unreachable reactor costs before you go live.

For a class-based reactor, mark the methods and collect them — bound methods keep their instance:

from axiam_sdk.amqp import on_reactor_event, reactor_handlers


class Reactor:
    @on_reactor_event(TOKEN_PRE_ISSUE)
    def enrich(self, event: ReactorEvent) -> ReactorDecision: ...


handler = reactor_handlers(Reactor())  # or reactor_handlers({TOKEN_PRE_ISSUE: fn})

It is pure sugar: the value it produces is exactly the handler reactor_serve already takes. It opens nothing, verifies nothing, signs nothing, does not filter a patch, and a handler's own exception reaches the runtime unchanged so nothing is published.

See examples/reactor.py for a complete three-hook reactor with graceful shutdown and a telemetry hook.

The five hookable events, and their allow-lists

An entry ending in . is a namespace prefix and needs at least one character after the dot: ext. admits ext.department and ext.a.b.c, and refuses ext. itself, ext, extra, external_id and evil.ext.department. So a reactor can never reach sub, aud, exp, scope or any other standard claim — a correctly signed reply setting sub is refused exactly as a forged one is.

Registrations that name no failure_policy get the strictest default among their events, in either array order — default_failure_policy_for([...]) computes it, and "take the first event's default" is specifically what §22.8 forbids, because it lets the order of a JSON array decide whether an unreachable fraud check passes.

The authorization hot path is not hookable, and this SDK does not pretend otherwise

The single check, the batch check and token introspection are absent from EVENT_REGISTRY, from REACTOR_EVENT_NAMES and from every example here (§22.7, a normative MUST NOT). A reactor round-trip is milliseconds; the check path's budget is microseconds. An application that needs external input on an authorization decision writes a deny grant, which the engine evaluates in the hot path at hot-path cost — and there is deliberately no client-side interceptor in this SDK offering itself as the reactor equivalent.

What the runtime guarantees

• Both directions are signed. The server signs the event with the tenant's HKDF-derived AMQP subkey; the reactor signs its reply with the same key. An unsigned or stale reply is not a weak reply — the server discards it as though the reactor had never answered. Every event is verified (key_version >= 2, MAC, ±300 s freshness in both directions, nonce seen-set) before your handler is called.
• Three canonicalization traps, all of them silent failures if missed. A reactor body signs hmac_signature as null, where §8's own two message types omit it; json.dumps must run with ensure_ascii=False, because serde_json escapes no non-ASCII and Python escapes all of it by default; and issued_at is chrono's RFC 3339 (…T12:00:00Z, no fraction on a whole second), not datetime.isoformat()'s +00:00 with six digits. All three are pinned by server-generated vectors rather than by memory — see testdata/reactor_v2_reference_vectors.json and tests/test_reactor_vectors.py.
• It declares no topology. No queue declare, no exchange declare, no bind — the server owns all three, and the transport protocol this runtime is written against does not even offer them. A reactor that can bind is a reactor that can bind itself to *.token.pre_issue and read another tenant's issuance events.
• It fails closed on its own errors. A handler that raises, a body that will not parse, a window that has already closed: each publishes nothing, so the registration's failure_policy decides. Synthesizing an allow would override the operator's fail_closed setting from inside the library. abstain() is the explicit form of the same thing.
• It does not filter your patch. One forbidden key rejects the whole patch server-side; pruning it here would leave you believing a field was set when it was dropped. Check yourself with patch_field_allowed(spec, field) if you want to know before you send.
• It honours timeout_ms. The handler runs inside the window the server declared, and a reply whose window has closed is abandoned rather than published late.
• Shutdown drains (§18). Cancel the reactor_serve task; it stops taking deliveries, lets every dispatch already running finish — handler, signature, publish — and only then closes the channel and connection.
• TLS is not optional (§8b). aio_pika_dialer accepts amqps:// only and refuses a plaintext URL rather than downgrading. ca_bundle= takes a path or inline PEM for a privately-issued broker certificate; there is no verification-skip switch under any name.

Registering a reactor (§22.9)

Registration is a REST admin call, not part of this runtime:

curl -X POST https://axiam.example.com/api/v1/reactors \
  -H "Authorization: Bearer $ADMIN_TOKEN" -H 'Content-Type: application/json' \
  -d '{"name":"fraud-check","events":["login.post_auth"],"mode":"intercept","timeout_ms":500}'

The response's id is what reactor_id takes, and the server declares the queue. timeout_ms defaults to 500 and is refused outside 1…5000; the chain's wall-clock ceiling is 5000 ms and the per-tenant in-flight cap is 64. This SDK exposes those as constants (DEFAULT_REACTOR_TIMEOUT_MS, MAX_REACTOR_TIMEOUT_MS, DEFAULT_REACTOR_MAX_IN_FLIGHT) but ships no typed client for the CRUD endpoints — call them through the REST client and let the server validate; §22.9 explicitly warns against re-deriving PUT merge semantics or the failure_policy re-derivation client-side.

Logging

The payload, patch, reason and decision are tenant business data — readable by design, since a handler that cannot inspect the event cannot decide anything, but this runtime never logs them at info level and yours should not either (§22.12). The signing key is never logged at any level and never appears in an error payload; signing_key_fingerprint() gives eight hex characters for an operational log instead. nonce, correlation_id and hmac_signature are not secrets and may be logged for correlation.

Local token verification (§10.1)

Both framework guards below verify the access token locally and therefore apply the complete CONTRACT.md §10.1 minimum local-verification set, through the single entry point JwksVerifier.verify_access_token(...):

from axiam_sdk._jwks import (
    DEFAULT_CLOCK_SKEW_SECONDS,
    RECOMMENDED_RESOURCE_SERVER_AUDIENCE,
    JwksVerifier,
)

verifier = JwksVerifier(
    base_url,
    expected_issuer="https://axiam.example.com",  # optional
    expected_audience=RECOMMENDED_RESOURCE_SERVER_AUDIENCE,  # optional
    clock_skew_seconds=DEFAULT_CLOCK_SKEW_SECONDS,  # bounded
)

JwksVerifier.verify_signature_only_unchecked(...) is the raw signature-only primitive §10.1 permits for integrators implementing their own policy. Its name states the omission: it checks no claims at all, and the SDK's own guards never call it.

FastAPI dependency (§10) — axiam-sdk[fastapi]

from fastapi import Depends, FastAPI
from axiam_sdk.fastapi import AxiamUser, JwksVerifier, require_authenticated_user

verifier = JwksVerifier(base_url)
authenticated_user = require_authenticated_user(verifier, "acme")

app = FastAPI()


@app.get("/protected")
async def protected(user: AxiamUser = Depends(authenticated_user)):
    return {"user_id": user.user_id, "tenant_id": user.tenant_id, "roles": user.roles}

See examples/fastapi_dependency.py.

Django middleware (§10) — axiam-sdk[django]

# settings.py
MIDDLEWARE = [..., "axiam_sdk.django.middleware.AxiamAuthMiddleware"]
AXIAM_JWKS_BASE_URL = "https://localhost:8443"
AXIAM_TENANT_SLUG = "acme"

# Optional §10.1 rule 5-7 settings; all default to unset / the recommended value.
AXIAM_EXPECTED_ISSUER = "https://localhost:8443"  # unset -> iss not checked
AXIAM_EXPECTED_AUDIENCE = "axiam:user"  # unset -> aud not checked
AXIAM_CLOCK_SKEW_SECONDS = 60  # bounded by MAX_CLOCK_SKEW_SECONDS

# views.py
def protected_view(request):
    user = request.axiam_user
    return JsonResponse({"user_id": user.user_id, "roles": user.roles})

See examples/django_middleware.py.

Declarative authorization helpers (§11)

Layered on top of the §10 authentication guards above, require_access / require_role add a per-endpoint AXIAM authorization check without hand- writing check_access(...) calls in every handler. They run strictly after authentication (never a separate/duplicated token-verification path) and check the request's authenticated caller (subject_id), never the SDK client's own — typically service-account — identity. Error mapping: unauthenticated -> 401; denied -> 403; an unresolvable resource id -> 400; a transport failure while calling the authz endpoint -> 503 (fail closed — never allow on a transport error). No decision caching: every request is a fresh check_access round-trip. require_role is a local, no-round-trip check against the verified identity's roles — cheaper but coarser, and NOT a substitute for require_access's authoritative, resource-level check.

FastAPI (axiam-sdk[fastapi]) — require_access takes the async AsyncAxiamClient:

from fastapi import Depends, FastAPI
from axiam_sdk import AsyncAxiamClient
from axiam_sdk.fastapi import AxiamUser, JwksVerifier, require_access, require_role

verifier = JwksVerifier(base_url)
authz_client = AsyncAxiamClient(base_url=base_url, tenant_slug="acme")

app = FastAPI()

require_doc_read = require_access(
    verifier, "acme", authz_client, "documents:read", resource_param="doc_id"
)


@app.get("/docs/{doc_id}")
async def get_doc(doc_id: str, user: AxiamUser = Depends(require_doc_read)):
    return {"message": f"user {user.user_id} may read document {doc_id}"}


require_admin_role = require_role(verifier, "acme", "admin")


@app.delete("/admin/cache")
async def reset_cache(user: AxiamUser = Depends(require_admin_role)):
    return {"message": f"cache reset by {user.user_id}"}

The resource id is resolved, in precedence order, from a literal resource_id= (singleton resources), a resource_param= path parameter name, or a resolver=lambda request: ... callback (body fields, headers, composite lookups) — exactly one must be supplied.

Django (axiam-sdk[django]) — require_access/require_role are view decorators reading request.axiam_user (set by AxiamAuthMiddleware) and take the sync AxiamClient:

from axiam_sdk import AxiamClient
from axiam_sdk.django.decorators import require_access, require_role

authz_client = AxiamClient(base_url="https://localhost:8443", tenant_slug="acme")


@require_access(authz_client, "documents:read", resource_param="doc_id")
def get_document(request, doc_id):
    user = request.axiam_user
    return JsonResponse({"message": f"user {user.user_id} may read document {doc_id}"})


@require_role("admin")
def reset_cache_view(request):
    return JsonResponse({"message": f"cache reset by {request.axiam_user.user_id}"})

Both async and sync Django views are supported (require_access/ require_role detect the wrapped view's dispatch mode automatically). resource_param defaults to "pk", matching the view kwarg Django's own URL path converters typically bind a captured resource identifier to.

See examples/fastapi_dependency.py and examples/django_middleware.py.

OIDC / SSO relying-party helpers (§12)

AxiamClient/AsyncAxiamClient expose the nine canonical §12 operations directly (this SDK has no browser-bundle constraint, so — unlike the TypeScript SDK's dedicated OidcClient — the methods live on the same client used for everything else). They let a backend application offer "Login with AXIAM" (authorization-code + PKCE against AXIAM's own OIDC provider), authenticate itself as a service account (client_credentials), introspect/revoke tokens, and drive the server's upstream-IdP federation endpoints:

Both AxiamClient (sync) and AsyncAxiamClient (async, async def twins under the same names, SDK-Q08) expose all nine — including oidc_begin, which performs no I/O but is still async def on the async client, per CONTRACT.md §12.2's Python naming table.

The caller owns the login state (§12.3 rule 1). oidc_begin returns state, nonce, and code_verifier and stores none of them anywhere — no process-global cache, no implicit session. Persist all three yourself (typically in your own HTTP session) between the login redirect and the callback, and pass nonce/code_verifier back into oidc_exchange explicitly. MemoryOidcStateStore (single-use consume, 10-minute TTL) is available for framework integrations that need somewhere to park that triple across the two HTTP requests of a redirect flow — it is optional and per-instance, never process-global.

from axiam_sdk import AxiamClient, OAuthProtocolError, AuthError

client = AxiamClient(
    base_url="https://localhost:8443",
    tenant_slug="acme",
    client_id="my-backend-app",
    client_secret="changeme",  # omit for a public client
)

configuration = client.oidc_discover()
request = client.oidc_begin(
    configuration=configuration,
    redirect_uri="https://app.example.com/oidc/callback",
    scope="openid profile email",
)
# ... persist request.state / request.nonce / request.code_verifier,
# redirect the browser to request.url, and receive the callback ...

try:
    tokens = client.oidc_exchange(
        code=callback_code,
        code_verifier=request.code_verifier,
        redirect_uri="https://app.example.com/oidc/callback",
        nonce=request.nonce,
        tenant_id="00000000-0000-0000-0000-000000000000",
    )
except OAuthProtocolError as exc:
    print(f"{exc.error}: {exc.error_description}")
except AuthError as exc:
    print(f"login failed ({exc.reason}): {exc}")
else:
    print(tokens.id_claims.sub if tokens.id_claims else "no id_token")

OAuthProtocolError is a language-idiomatic sub-type of AuthError (CONTRACT.md §2/§12.3 rule 3) — existing except AuthError: code keeps matching it unchanged. It carries error/error_description and str(exc) == "<error>: <error_description>". Every §12.4 ID-token validation failure raises the plain AuthError with a stable reason — one of invalid_alg, unknown_kid, invalid_signature, invalid_issuer, invalid_audience, token_expired, nonce_mismatch.

access_token, refresh_token, id_token, client_secret, and code_verifier are all pydantic.SecretStr (§7/§12.5) — never printed or serialized in the clear; read the raw value via .get_secret_value(). state/nonce are plain strings (§12.3 rule 2 — not secrets).

Framework glue. axiam_sdk.fastapi.oidc_login_router(client, redirect_uri=...) builds a two-route APIRouter (login redirect + callback); axiam_sdk.django.oidc.oidc_login_views(client, redirect_uri=...) builds a (login_view, callback_view) pair sharing one state store. Both delegate entirely to the operations above and to the existing session/cookie machinery — see examples/oidc_login.py.

OPAQUE (§23)

login_opaque authenticates the password without sending it. What crosses the wire is a blinded group element and a MAC, neither useful without the account's registration record and the tenant's OPRF seed.

# Same LoginResult as login(), including the mfa_required case.
result = client.login_opaque("alice", "correct horse battery staple")

Unlike the SRP-6a this replaces, it returns without verifying a server proof separately, and nothing is missing: RFC 9807's AKE authenticates the server during the handshake, so opening KE2 is the proof that it holds the record. The old contract had to mandate an M2 check in capitals because skipping it kept only half the protocol; there is now nothing to skip.

Fall back to login() when the tenant does not offer OPAQUE. That case is a NetworkError, deliberately not an AuthError, so it cannot be mistaken for a bad password:

try:
    result = client.login_opaque(user, password)
except NetworkError as exc:
    if "opaque_mode is disabled" not in str(exc):
        raise  # a KSF this build cannot perform — not a fallback case
    result = client.login(user, password)

AuthError from login_opaque is the whole of the authentication check, and covers both halves of the mutual authentication: a wrong password, an account that does not exist, and a server that does not hold the record are indistinguishable by design. Do not retry over login() — that hands the plaintext to an endpoint that just failed to prove it holds the record (§23.4 rule 7).

Enrolment

The server cannot build a registration record — it never sees the plaintext — so one has to be sent with any request that sets a password:

enrollment = client.opaque_enrollment("new password")
# send enrollment["registration_record"] and enrollment["opaque_session"]
# as the request's `opaque` object

It is async/one round trip because OPAQUE's envelope is sealed under the server's oblivious PRF: there is no offline computation that produces a valid record. Note the absence of an identity argument. The SRP version required the account's canonical username, and passing an email produced a verifier no login could ever satisfy; a record binds to a credential identifier the server chooses, so there is nothing here to get wrong — and a later rename cannot invalidate a credential.

There is also no group or kdf argument. The key-stretching function comes from the */start response, every time: a credential enrolled under one cost keeps working after a tenant raises its policy, so a client that used local defaults would derive a different randomized password and fail against a good record.

Installing

The protocol itself is not in this SDK. CONTRACT.md §23.1 forbids an SDK from implementing OPAQUE — it needs an oblivious PRF, hash_to_curve, expand_message_xmd, an envelope construction and a three-message AKE, and eleven independent implementations of that is eleven chances to be subtly and silently wrong. What ships here is a ctypes binding to libaxiam_opaque_ffi, the same implementation the AXIAM server links.

That library is a Rust cdylib published as a per-platform asset on the axiam release page, not a PyPI distribution — so there is no axiam-sdk[opaque] extra, and a name that installed nothing while reading as though it installed the thing would be worse than its absence. Put the file on the loader path, or point an environment variable at it:

export AXIAM_OPAQUE_LIBRARY=/opt/axiam/libaxiam_opaque_ffi.so

Ask before you need it:

if client.opaque_available():
    result = client.login_opaque(user, password)
else:
    result = client.login(user, password)

It reports rather than raising, so an application can choose the password path up front instead of discovering the gap mid-exchange. When it is absent, login_opaque raises a NetworkError naming the artifact and the environment variable — never something that looks like a wrong password.

Two things that will bite you

It blocks, and on AsyncAxiamClient it blocks the event loop. The KSF is CPU-bound: Argon2id at 19 MiB by default, tens to hundreds of milliseconds. That cost is what makes a stolen record expensive to attack even by someone holding the OPRF seed. On a server handling other requests, wrap the call in asyncio.to_thread.

What it protects, and what it does not. A TLS-terminating proxy, an accidentally verbose request log, or a heap dump on the server cannot capture a plaintext password, because the server never has one — and a stolen record database is not offline-crackable on its own without the tenant's OPRF seed, which is the pre-computation resistance SRP could not offer. It does not protect against a compromised AXIAM server.

See examples/opaque_login.py.

Device authorization grant (§14)

RFC 8628 — signing in a device that cannot show a browser: a TV, a CLI, a headless commissioning tool. device_authorize, device_poll and the composed device_login, on both AxiamClient and AsyncAxiamClient.

def show(auth: DeviceAuthorization) -> None:
    # Called BEFORE the first poll. Display it however the device can —
    # screen, QR code, e-ink panel. The SDK never prints it for you.
    print(f"visit {auth.verification_uri} and enter {auth.user_code}")


tokens = client.device_login(show, scope="openid profile")

The polling rules are where implementations go wrong, so they are worth stating:

• slow_down raises the interval permanently. An SDK that backs off for one round and returns to the original interval will be told to slow down again, forever.
• access_denied and expired_token stay distinct. A human said no, versus nobody answered — the only information the device can act on.
• Polling stops at expires_in, even if the server has not yet said expired_token.
• A 5xx mid-poll is not terminal. A server restart must not lose a grant the user has already approved.

device_code is a SecretStr; user_code deliberately is not — it exists to be read aloud, and wrapping it would defeat the one thing it is for.

device_authorize sends no client_secret and does not refuse a client built without one: a device that cannot show a browser cannot keep a secret either. The async device_login awaits an async callback before polling, so a device that needs to await a paint still satisfies §14.3 rule 2.

Per §14.3 rule 4, device_login returns the token set rather than adopting it, matching this SDK's login_client_credentials posture. See examples/device_login.py.

Token exchange (§15)

RFC 8693 — a service holding a user's token exchanging it for a narrower one before calling the next service.

from axiam_sdk import ACCESS_TOKEN_TYPE

exchanged = client.token_exchange(
    subject_token=user_token,
    subject_token_type=ACCESS_TOKEN_TYPE,  # required (§15.1), no default
    scopes=["orders:read"],
    audience="orders-service",
)

Most of what this method does is refuse to be helpful, and each refusal is deliberate:

• No default actor_token. Omitting it asks for impersonation; the SDK will not quietly substitute the client's own session token and turn that into a delegation.
• No auto-narrowing after invalid_scope. The server refuses rather than silently narrowing precisely so the caller finds out here.
• No refresh token, ever — ExchangedToken has no such field, so there is nothing to synthesise. Re-run the exchange.
• No adoption. The issued token is handed onward in one call; adopting it would silently re-privilege every later call this client makes. A MUST NOT, where login_client_credentials adoption is a MAY.

See examples/token_exchange.py.

External-IdP subject tokens (§15.7)

The same method exchanges a token minted by a trusted external IdP — a partner's Entra, Okta or Keycloak — for an AXIAM token scoped to what the resolved AXIAM user may actually do. There is no separate operation:

from axiam_sdk._oidc import JWT_TOKEN_TYPE

exchanged = client.token_exchange(
    subject_token=partner_token,
    subject_token_type=JWT_TOKEN_TYPE,  # named, never guessed
    scopes=["read:orders"],
    audience="https://orders.internal",
)

• subject_token_type is yours to state, and is required (§15.1). The SDK never decodes the subject token to pick it, and never overrides what you named. There is no default — omitting it raises TypeError before any wire call, because a default would be the SDK choosing for you.
• No actor token. Delegation across a trust boundary is unsupported in v1; sending one is invalid_request, which the SDK will not work around by dropping it and re-sending.
• One refusal is distinguishable. invalid_grant whose description is the subject token's issuer is not configured for token exchange means fix the AXIAM trust configuration. Every other invalid_grant means fix your token, and is deliberately generic.
• Forward the result as-is. It carries an ext_exchange claim naming the partner issuer; never strip it, and never read it as an authorization input. It also cannot be exchanged again — exchanges do not compose.

The operator guide is docs/api/federated-token-exchange.md.

Logout — RP-initiated and back-channel (§12.7)

logout_url builds the redirect; verify_logout_token validates a token the OP pushed to your back-channel endpoint.

url = client.logout_url(id_token=stored_id_token)

# …and at your registered backchannel_logout_uri:
verified = client.verify_logout_token(logout_token)
if verified.sid is not None:
    end_session(verified.sid)  # that session ONLY

The verifier is where the security weight sits — the input arrives unsolicited and instructs you to terminate a session. It checks the signature (same JWKS path, same kid-required discipline as §12.4), iss, aud, that events carries the back-channel-logout key (the only thing separating a logout token from an ID token), that nonce is absent (its presence is how an ID token gets replayed as one), that something is named, and freshness.

It returns sid/sub/jti rather than a bare bool: you have to know which session to end. Dedup on jti yourself — delivery is at-least-once, so a valid token legitimately arrives twice; the SDK has no durable store and an in-memory guard would silently drop a real second logout after a restart.

See examples/logout.py.

Webhook signature verification (§13)

axiam_sdk.webhook.verify_webhook(secret, signature_header, body) verifies the X-Axiam-Signature: t=<unix_seconds>,v1=<hex> header AXIAM sends on every webhook delivery — HMAC-SHA256 over "<timestamp>.<raw_body>", compared in constant time, with a two-sided freshness window (default 300s):

from axiam_sdk.webhook import WebhookVerifyError, verify_webhook


# Flask: request.get_data() is the RAW bytes off the wire. Do NOT verify
# against request.get_json() re-dumped — re-serializing changes key order/
# whitespace and breaks the MAC (CONTRACT.md §13.3 rule 1).
@app.post("/webhooks/axiam")
def axiam_webhook():
    try:
        event = verify_webhook(
            secret=WEBHOOK_SECRET,  # a pydantic.SecretStr or plain str
            signature_header=request.headers["X-Axiam-Signature"],
            body=request.get_data(),  # raw bytes, NOT re-serialized JSON
        )
    except WebhookVerifyError:
        return "invalid signature", 400

    # X-Axiam-Delivery (event.delivery_id, if you pass it through — see
    # below) is the at-least-once dedup key: retries replay a validly-
    # signed delivery inside the freshness window, so keep a short-lived
    # seen-set if double-processing an event would be unsafe.
    ...
    return "", 200

FastAPI is the same shape with await request.body() in place of request.get_data() — both give you the exact raw bytes the server signed; await request.json() does not, for the same re-serialization reason.

verify_webhook also accepts event_type/delivery_id (pass the raw X-Axiam-Event/X-Axiam-Delivery header values straight through — neither is covered by the MAC) so the returned WebhookEvent carries them, a tolerance override (seconds, default 300), and a now injection seam for tests. WebhookVerifyError's message never includes the expected/computed signature or the secret.

gRPC stub generation (D-04)

pip install-ing this package does not require buf/protoc — the generated gRPC stubs (src/axiam_sdk/grpc/gen/) are committed and shipped in both the wheel and the sdist. Contributors regenerating them locally run:

bash scripts/gen_grpc.sh

CI regenerates the same way and fails the build on any drift (git diff --exit-code) between the committed stubs and a fresh regeneration from proto/axiam/v1/.

TLS policy (§6)

httpx clients are constructed with verify=True hardcoded; the only escape hatch is an explicit custom_ca parameter (a CA bundle path or ssl.SSLContext) — there is no boolean bypass anywhere in this SDK, including the examples. CI enforces this with a dedicated grep gate.

mTLS / client certificates (§6.1)

For IoT devices and service accounts that authenticate by mutual TLS, pass a PEM client-certificate chain plus its PEM private key (each str or bytes). The same identity is applied to both the REST and gRPC transports of the client, and presenting it never relaxes server verification — strict TLS (§6) stays fully on.

from axiam_sdk import AxiamClient

with open("device-cert.pem", "rb") as f:
    client_cert = f.read()
with open("device-key.pem", "rb") as f:
    client_key = f.read()

client = AxiamClient(
    base_url="https://axiam.example.com",
    tenant_slug="acme",
    custom_ca="/etc/axiam/org-ca.pem",  # server trust (optional; system roots by default)
    client_cert=client_cert,  # PEM cert chain (str or bytes)
    client_key=client_key,  # PEM private key (str or bytes)
)
# AsyncAxiamClient(...) takes the identical client_cert=/client_key= parameters.

client_cert and client_key must be supplied together (only one is a construction-time error), and a non-PEM value is rejected at construction. The private key is secret material: it is loaded straight into the TLS stack and is never logged, stored as a public attribute, or exposed via a getter (§6.1 rule 3 / §7). The gRPC authorization clients accept the same client_cert=/client_key= parameters.

Development

pip install -e ".[dev,fastapi,django]"
pytest tests
mypy --strict src
ruff check .
ruff format --check .

Coverage (as CI runs it, reported to Coveralls):

pytest --cov=axiam_sdk --cov-report=lcov

Client quality-of-life (CONTRACT.md §16–§19)

Retry policy (§16)

Read-only authorization checks — check_access, can, batch_check, on both the sync and async clients — retry transient failures under the contract's normative table: 3 attempts (1 initial + 2 retries), 200 ms base, 5 s cap, full jitter (uniform over [0, backoff]), and Retry-After honored as a floor.

This SDK had no §16 policy before — only §9.3's refresh-then-retry-once, which is a different mechanism. §11.2 rule 5 had been requiring one since it was written.

Only failures that could plausibly succeed on a second attempt are retried: transport errors, 408, 429, 5xx. A 401 or 403 is an answer, not a transport failure, and surfaces after exactly one attempt. Nothing that changes server state is ever retried.

# Turn it off if you own your own retry layer — you know your deadline, this SDK doesn't.
client = AxiamClient(base_url=..., tenant_slug="acme", retry_enabled=False)

There is deliberately no knob for the attempt cap, base delay or delay cap: §16.1 forbids raising them, and eleven SDKs agreeing on one table is the point.

Deterministic shutdown (§18)

client.close() (sync) and await client.aclose() (async) release local resources. Both are idempotent, and any call afterwards raises NetworkError naming the cause rather than silently reconnecting.

Neither logs out. They never reach the network. The server-side session deliberately outlives the client object — that is what lets a process restart and resume — so a close() that logged out would silently end every user's session on each deploy. Call logout() first if ending the session is what you want.

Telemetry hooks (§19)

Wire metrics without this package depending on any metrics library:

from axiam_sdk import AxiamClient, RequestEnd, Retry, TelemetryEvent


def sink(event: TelemetryEvent) -> None:
    if isinstance(event, RequestEnd):
        histogram.record(event.duration_ms, {"op": event.operation, "outcome": event.outcome})
    elif isinstance(event, Retry):
        counter.add(1, {"op": event.operation, "attempt": event.attempt})


client = AxiamClient(base_url=..., tenant_slug="acme", telemetry_hook=sink)

• A hook that raises cannot fail the operation that fired it. Telemetry is not permitted to fail an authorization check.
• No event payload can carry a token. The event dataclasses are frozen with a fixed field set — this surface exists to be shipped to a metrics backend.
• Path templates, not URLs, so a metric label cannot become a cardinality bomb.

One RequestStart/RequestEnd pair is emitted per attempt, so you can count real wire calls. See examples/telemetry_hook.py for the OpenTelemetry mapping.

Decision memo (§17) — opt-in, off by default

An optional TTL-bounded cache for check_access results. Disabled by default, because §11.2 rule 6's ban on caching authorization decisions is still the default behaviour.

client = AxiamClient(base_url=..., tenant_slug="acme", decision_memo_ttl_ms=5000)  # 0 = off

What you are accepting. The staleness bound is the TTL, in both directions: a grant revoked on the server can still read as allowed for up to the TTL, and a grant just added can still read as denied for up to the TTL.

Reads-your-own-writes is not guaranteed. An admin UI that grants a role and immediately re-checks is the case that breaks, and it breaks silently. If that is your workload, leave this off.

The TTL is clamped to 5000 ms rather than rejected. Allows and denies are memoized identically — asymmetric caching would leak which outcome occurred through latency. Failures are never memoized: caching a transport error as a deny would turn a blip into a TTL-long outage. The memo is cleared on login, verify_mfa, refresh and logout, since entries are keyed by subject rather than by session. It is thread-safe.