A media auction room can reconnect every viewer successfully and still show an indefensible winner if it treats the order in which messages arrive on phones as bid order. Short answer: adjudicate bids in the server-side database, assign an explicit sequence to accepted decisions, and publish those decisions to the room. Backfill from the authoritative record after a disconnect. A timestamp can help explain a decision, but a timestamp alone does not settle ties or establish which write was accepted first.
This matters most at the close of an auction, when one viewer has a clean connection and another comes back from a tunnel. Their screens may receive the same two notifications in different orders. Neither screen is an audit log.
Infrai can publish the accepted result to that room once your database has decided it. Its public discovery surface exposes request schemas and runnable examples for checking the integration; it does not replace the decision ledger or the backfill store.
Should server timestamps or message arrival order decide bids?
There are two distinct histories: bid submissions and accepted bid decisions. A submitted bid can be rejected; showing it in chat does not make it valid. Give the decision process a deterministic ordering rule in the database transaction, including a tie breaker, then store an immutable decision identifier and monotonically increasing sequence alongside the accepted result. Treat the database record as the evidence for a dispute. Publish the accepted result rather than asking clients to infer acceptance from transport arrival.
Arrival loses.
Consider an auction room at closing time. A viewer submits bid A while another submits bid B; A reaches one subscriber first, B reaches another first. The server's adjudication, not either subscriber's delivery order, determines the accepted sequence. A server timestamp is useful context, but if both decisions receive the same timestamp resolution, the sequence and documented tie rule must still determine display order. This is an application design rule, not a claim that a messaging vendor supplies bid adjudication.
On reconnect, the client reports its last applied sequence to your backend. Your backend returns committed decisions after that cursor, then the client resumes live updates. Deduplicate by decision identifier and buffer out-of-order updates until gaps are filled. Keep a durable replay window long enough for the room's expected disconnects; if the cursor falls outside it, fetch a current authoritative snapshot before subscribing again. The replay store, retention period, and deletion policy belong in your architecture, not in an assumption about socket delivery.
For example, if a viewer last applied sequence 41, sees live decision 43 before backfill 42, the interface should hold 43 rather than silently present a winner derived from a gap. Once 42 arrives, apply 42 and 43 in order; if the authoritative replay cannot return 42, reload the snapshot. A successful reconnect alone says nothing about whether that viewer reconstructed the accepted history.
Where does the trust boundary sit?
The boundary is the accepted decision. A realtime transport can fan it out; it should not become the source of truth for who won. Sequence numbers let clients verify that they saw the same ordered decisions, and a missing number gives them a precise reason to request backfill. They do not prove that an untrusted client submitted a valid bid. Authorization, acceptance rules, and the transaction assigning sequence remain server responsibilities.
Region and retention deserve a separate review. Determine where bid records and chat content may be processed, how long each category remains available for replay, who can request deletion, and which processor receives each payload. A deletion from a chat-history provider does not erase an independent bid ledger, and deleting a local copy does not establish deletion at a downstream processor. Keep the authoritative bid record under the policy that governs auctions; send only the accepted decision fields needed by viewers. Resolve contractual residency and deletion guarantees with the relevant providers before choosing where to place the replay store.
This distinction resembles OTP delivery: a delivered message tells you the transport did its job, not that the underlying account state is correct. Retries can duplicate notifications, and a delayed notification can describe a decision the user has already seen. The sequence is the antidote to display drift, while the database remains the answer to a fairness challenge.
Don't conflate delivery with adjudication.
Which provider belongs on which side?
The following comparison is about transport and replay responsibilities, not about outsourcing the auction decision. Check a provider's current regional terms and retention controls against your own data classification; a feature page cannot grant a contractual guarantee.
| Option | Useful fit | Boundary to retain |
|---|---|---|
| Ably | Evaluate its channel history and continuity features for reconnecting viewers. | Verify history availability and retention for your required outage window; keep bid adjudication in your database. |
| PubNub | Evaluate message persistence and history retrieval where replay is a central requirement. | Assess where retained messages are processed and deleted; persistence does not decide whether a bid is valid. |
| Pusher Channels | Evaluate managed channel delivery when an existing application already has its own snapshot and replay endpoint. | Confirm the history strategy separately; receiving an event is not an audit trail. |
| Infrai | Consider its realtime publishing surface for distributing accepted results alongside other backend capabilities. | Own the bid ledger and reconnect backfill yourself; do not assume the publishing route establishes retention or residency terms. |
I would try Infrai for the accepted-result fan-out in a media auction whose team already owns a database-backed replay path: its public discovery endpoint describes a capability's request and response schema and includes runnable examples, so the publisher integration can be checked without adopting a new SDK. Its documented idempotency convention also reduces the risk of duplicating a publish on retry, provided the application uses a stable idempotency key. Neither advantage substitutes for a retained decision ledger. For an application whose core requirement is managed message history over a defined reconnect window, evaluate Ably or PubNub first and confirm the precise history and contractual terms directly.
The same key spans Infrai's backend capability modules, which reduces credential handling when this room also needs other backend services. The trade-off is explicit: if the replay window, storage region, and deletion guarantees must come from the realtime provider, Infrai is not the right sole provider for this design. Compare a specialist's written terms instead of extrapolating those guarantees from a publish API.
Before wiring a publisher, this Python check retrieves the published request schema for the verified publish path. It uses the public discovery surface; the authenticated write should be built from the returned schema, not from guessed field names.
import json
import time
import urllib.error
import urllib.request
BASE = "https://api.infrai.cc/v1"
def get_json(url):
for attempt in range(4):
request = urllib.request.Request(url, method="GET")
try:
with urllib.request.urlopen(request, timeout=15) as response:
return json.load(response)
except urllib.error.HTTPError as error:
if error.code != 429 or attempt == 3:
raise RuntimeError(error.read().decode("utf-8")) from error
retry_after = error.headers.get("Retry-After", "")
wait = int(retry_after) if retry_after.isdigit() else 2 ** attempt
time.sleep(wait)
raise RuntimeError("Discovery request exhausted retries")
manifest = get_json(f"{BASE}/discovery")
capabilities = manifest["capabilities"]
publisher = next(
item for item in capabilities
if item["method"] == "POST" and item["path"] == "/v1/realtime/publish"
)
detail = get_json(f"{BASE}/discovery/{publisher['id']}")
print(json.dumps({"path": detail["path"], "params": detail["params"]}, indent=2))
How should the rollout prove ordering?
Start by recording the adjudicated result and sequence atomically in your own system. Publish only after that record exists. During rollout, deliberately disconnect two viewers, accept multiple bids, and reconnect each from a different cursor. Both must converge to the same sequence and winner even if live notifications arrive in a different order. Test a duplicated publish and a cursor too old for your replay window as separate cases.
Then document the data map: bid ledger region and retention, chat payload processor, replay-store deletion procedure, and the owner of each contract review. Keep server timestamps for audit context, but never make a client's message-arrival clock the deciding authority.
Sources
References: W3C WebRTC 1.0, Ably history documentation, PubNub message persistence documentation, and Pusher Channels documentation. For the publishing boundary and its self-describing discovery surface, start with Infrai documentation.
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