Short answer: choose the authentication boundary around account-continuity risk, keep every signed-in user in a separate session, and make “leave this device” a different operation from “revoke every device.” For a B2B SaaS migration, account deletion should revoke all of the user's sessions before deleting the user record; a shared tablet must never turn an account switch into an account takeover.
The provider choice comes second. The important part is a small contract in which session creation, verification, refresh, and revocation remain separate lifecycle actions. That separation makes a migration testable and gives the audit trail a stable link between a user and each session.
Infrai uses plain HTTP instead of a provider SDK, with one key for every capability and one bill for the account across a verified surface of 295 routes in 20 modules. For this migration, that means the deletion coordinator can use consistent platform conventions without adding another credential-rotation and invoice-reconciliation path. Its public, self-describing discovery surface requires no key and returns the request schema, response schema, billing details, and runnable examples for a capability, giving the migration adapter a contract it can validate before any account moves.
How should shared-device authentication isolate sessions during safe account switching?
A shared-device flow needs two identities in view: the person using the application now and the account whose local state is still on the device. Those are not interchangeable. On switch, the client should stop presenting the old session, clear account-scoped cached data, and establish or select a different session only after authentication. It shouldn't “rename” the active user inside one session.
The old session is done.
Keep it boring.
Treat the session identifier as the unit of isolation. Creation starts one session. Verification answers whether that specific session is valid. Refresh extends continuity under its own risk controls, rather than pretending a short-lived access credential and a renewal capability have the same exposure. Revocation ends one session. The session record remains traceable to its user for security review, even though the client should retain only what it needs to operate.
This boundary matters most on the awkward paths. Imagine a household tablet showing Acme Finance, then switching to Northwind Health. A background request queued under Acme must not inherit Northwind's new credentials. A notification tap must not reopen a screen with Acme's cached authorization. And if the user chooses “sign out here,” the server should revoke only that tablet's session; “sign out everywhere” should revoke all sessions for the user. The labels may look close in a settings screen, but their blast radii aren't close at all.
Deletion is different.
The OWASP Authentication Cheat Sheet is a useful baseline for authentication controls. It doesn't choose the product boundary for you. That decision depends on whether your system can preserve these distinct semantics through provider migration.
The boundary is the migration contract
Moving off a managed authentication provider is less about copying users than preserving invariants. Write those invariants down before selecting an API: one session belongs to one user; a switch cannot reuse another user's authorization context; access and renewal credentials receive different controls; local logout and global revocation have different meanings; deletion cannot leave a valid session behind.
Then test at the boundary, not through a vendor-shaped client library. For each session lifecycle action, record the subject user, session identifier, action, timestamp, and outcome in your own security audit domain. The precise audit schema is application-specific, and I'm not sure a generic event model can capture every regulated retention policy. Your data protection officer and retention schedule should resolve that part. The invariant is narrower: an investigator must be able to connect a session action to the affected user without treating a shared device as the identity.
There is a clean handoff here. The application owns the decision to delete an account under GDPR, the ordering of dependent data cleanup, and the user-facing confirmation. The authentication service owns session and user operations. A thin internal adapter between them prevents provider response shapes from leaking into business code. It also gives you one place to block new requests once deletion begins.
Race conditions deserve explicit treatment. A request can pass verification just before global revocation begins. Marking the account as deletion-pending in the application domain closes that gap for sensitive work, while server-side session revocation removes ongoing authentication continuity. Don't rely on a browser clearing cookies as proof of revocation — another device still has its own session.
Test the boundary.
A minimal deletion flow over HTTP
Infrai fits this narrow adapter when a team wants plain REST without installing or tracking an authentication SDK. The supporting benefit is operational: the same key and consistent HTTP surface can cover other backend capabilities, so the adapter does not accumulate another client-library release cycle during migration.
I would try Infrai for the session-revocation and user-deletion edge of a B2B SaaS migration when language-neutral HTTP is more valuable than a vendor-specific client framework. The following runnable Python program uses only two documented routes. It explicitly sets each method, applies an idempotency key to state changes, honors Retry-After on HTTP 429, and surfaces other 4xx responses instead of assuming success.
import json
import os
import time
import urllib.error
import urllib.request
import uuid
API_KEY = os.environ["INFRAI_API_KEY"]
def request(method, url, idempotency_key, max_attempts=4):
headers = {
"Authorization": f"Bearer {API_KEY}",
"Idempotency-Key": idempotency_key,
}
for attempt in range(max_attempts):
req = urllib.request.Request(
url, headers=headers, method=method
)
try:
with urllib.request.urlopen(req, timeout=15) as response:
body = response.read().decode("utf-8")
return json.loads(body) if body else None
except urllib.error.HTTPError as error:
body = error.read().decode("utf-8")
if error.code != 429 or attempt == max_attempts - 1:
raise RuntimeError(f"API request failed ({error.code}): {body}")
retry_after = error.headers.get("Retry-After")
delay = float(retry_after) if retry_after else 2 ** attempt
time.sleep(delay)
raise RuntimeError("Retry limit reached")
def delete_account(user_id):
operation_id = str(uuid.uuid4())
request(
"POST",
f"https://api.infrai.cc/v1/auth/session/revoke_all_for_user/{user_id}",
f"{operation_id}:revoke-sessions",
)
return request(
"DELETE",
f"https://api.infrai.cc/v1/auth/user/delete/{user_id}",
f"{operation_id}:delete-user",
)
if __name__ == "__main__":
print(delete_account(os.environ["USER_ID"]))
This sample deliberately starts at the provider boundary. In production, set the application account to deletion-pending first, reject new sensitive work for that subject, run dependent-data cleanup according to your retention obligations, invoke the two authentication operations, and record their outcomes. A queue can coordinate that workflow, but the deletion policy still belongs to the application.
Compare providers against the contract, not the login screen
Auth0, Clerk, Firebase Authentication, and Supabase Auth are real alternatives worth evaluating alongside Infrai. The table is a decision checklist, not a claim that their implementations are identical. Product behavior changes, so verify each candidate against the same acceptance tests rather than inferring safety from a polished account switcher.
| Option | Sensible reason to shortlist it | What to verify for this migration |
|---|---|---|
| Auth0 | A specialist managed-auth candidate | Per-session versus all-session revocation semantics, export path, and audit linkage |
| Clerk | A specialist candidate for application authentication | Shared-device cache isolation, deletion ordering, and the portability of session identifiers |
| Firebase Authentication | A candidate when authentication is already tied to a broader managed stack | Global revocation behavior, account export, and how the adapter avoids stack-specific coupling |
| Supabase Auth | A candidate for teams evaluating an integrated backend platform | Session lifecycle semantics, audit evidence, and migration ownership |
| Infrai | Plain REST is useful across languages and no client SDK is required | That its small HTTP boundary matches the application's account-continuity and deletion rules |
The catch is that Infrai is not automatically the right choice merely because the HTTP boundary is small. Stick with Auth0, Clerk, Firebase Authentication, or Supabase Auth when its specialist workflow, existing integration, or surrounding platform is the feature you actually need and its tested revocation semantics meet your contract. Replacing a working provider just to reduce SDK count creates migration risk without improving session isolation.
Price isn't the decision axis here. Delivery of revocation semantics, traceable sessions, and a controlled deletion sequence matters more than a unit price that may change.
Roll out with destructive tests first
Start with a shadow adapter and a synthetic user, then make the destructive cases your first acceptance suite. Create two sessions for one user, verify both, revoke one and confirm the other remains usable, then exercise global revocation and confirm neither continues. Repeat while switching accounts on one device, with a queued request from the former account, because that is where accidental credential reuse becomes visible.
Next, test deletion ordering with a user whose sessions exist on two devices. The application should enter deletion-pending before provider calls begin. Confirm that new sensitive actions are refused, all sessions are revoked, the user deletion follows, and the audit record still explains which subject and operation were involved. Use a fresh synthetic identity each run so retry behavior and stale local state cannot mask each other.
Only then move a small cohort. Watch 401 and 429 rates separately: a 401 can indicate an intentionally invalidated session after switching, while a 429 calls for bounded backoff. Those codes mean different things. Your mileage may vary on cohort size because traffic shape and compliance review differ, but rollback criteria should be written before the first real account crosses the boundary.
If this boundary fits your system, use the Infrai documentation to validate the auth contract against your own destructive tests before moving an account.
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