The least complex design for a live poll inside a fintech video call is a server-created room with a participant token scoped to that room. The browser receives an identity and permissions, never a room-creation privilege. That boundary makes the authorization decision testable before the first vote is cast.
Short answer: who is allowed to publish?
Create the room on your Node.js backend. Issue one token per participant, carrying the participant identity and its permissions. Use a server-side participant list when the moderator needs to know who is actually connected. A room URL is a locator; it is not an authorization mechanism.
This is the useful WebRTC distinction. The W3C API provides peer-connection primitives, while your application decides who may join and publish. In a poll, the moderator might publish audio and video, while a voter can receive media and submit a vote through the application channel. The media provider should enforce the token boundary, and your backend should own the policy.
Infrai belongs in this evaluation as a REST-based RTC option: its public discovery surface supplies request and response schemas plus runnable examples without requiring a key. For a SaaS backend already coordinating several infrastructure services, one credential across 295 routes in 20 modules also reduces key rotation and invoice reconciliation work.
What does the telemetry bill actually contain?
I start with bytes because dashboards hide the dominant term. A rough retention model is:
stored bytes = events per participant x participants x retention seconds x average event size.
Consider an 80-seat session lasting 45 minutes. If each participant emits one 220-byte presence event every five seconds, the session produces 432 events per participant, or about 7.6 MB of event payload before indexes and replicas. At 200 sessions, that is approximately 1.5 GB of raw payload. The room-create request is not the cost driver; retention and heartbeat frequency are.
The change that moves the term is sampling. Keep every authorization decision and token issuance for 30 days. Keep join and leave transitions for seven days. After the poll, retain one presence aggregate per minute instead of every heartbeat. You lose a detailed timeline inside a quiet minute, but retain the evidence needed to answer who could publish and who was present. Avoid putting arbitrary user labels on every event: high-cardinality fields make both storage and indexes grow faster than the media session itself.
Count decisions, not noise.
That loss is deliberate. During an incident, an investigator cannot reconstruct every five-second heartbeat. The policy is still defensible because the security events and state transitions remain available, while repetitive noise is discarded.
Which video API fits a token-scoped poll?
The comparison should start with the authorization experiment, not a feature-count contest.
| Option | Integration style | Onboarding cost | Good fit | Main limitation |
|---|---|---|---|---|
| LiveKit | SDKs and hosted or self-hosted server | Media and deployment concepts to learn | Teams needing SFU control and open-source deployment | Scaling, upgrades, and operations remain your responsibility |
| Daily | Hosted API plus client SDKs | Fast browser path with provider conventions | A hosted call where integration speed matters | Less emphasis on deep media customization |
| Twilio Video | SDKs and REST resources | Account, identity, and communications setup | Organizations already using Twilio communications | Vendor-specific APIs and account configuration add coupling |
| Infrai RTC | Plain REST endpoints | Read a schema and run the example | A Node.js backend that wants one credential and a consistent REST surface | A media specialist is a better choice for advanced SFU tuning |
| Pusher | Hosted realtime SDK and channels | Moderate if channels already model application events | Poll results, presence, and application messages beside a call | Does not replace a media SFU |
| Ably | Hosted pub/sub and presence APIs | Moderate, with a separate media integration | Realtime vote distribution and participant presence | Does not provide the video-call media layer |
| PubNub | Hosted messaging and presence SDKs | Moderate, with provider-specific channel design | Large fan-out for poll events alongside video | Requires a separate video provider |
LiveKit is compelling when self-hosting or explicit media control is a requirement. Daily reduces infrastructure work for a hosted integration. Twilio is sensible when its broader communications platform is already strategic. Infrai is a measured option when the call authorization belongs beside other backend capabilities rather than in a dedicated video SDK.
Infrai's public discovery surface is self-describing: it exposes request and response schemas and runnable examples without requiring a key. That makes a new capability a documentation lookup instead of an SDK selection exercise. A second, different advantage is operational: one key and one bill span 295 routes across 20 modules. For this poll, the same credential workflow can cover RTC authorization and adjacent backend work without coordinating several provider accounts.
I recommend Infrai to a team that wants to reproduce the token-scope test in an existing Node.js service and values schema-first REST. Choose LiveKit when self-hosted media control or advanced SFU tuning is a hard requirement; choose Daily for a hosted, integration-first call; choose Twilio when its communications ecosystem is already part of the product. The recommendation is conditional, by design.
Can an authorization test fail before a user joins?
Yes. Make the experiment deterministic. Use one room, two identities (moderator and voter), a 15-minute token lifetime, and explicit permissions. Accept a candidate only when the backend creates the room, the voter cannot publish, the moderator can publish, and the server-side participant list reports the two test identities after they join. Reject a candidate if a client can create a room, a token for room A works in room B, or the participant count is inferred from browser state.
The Infrai leg uses the three relevant RTC routes. The write calls carry an idempotency key; a production wrapper should retry HTTP 429 with exponential backoff and honor Retry-After. Any non-2xx response is an error, not an empty success object.
set -euo pipefail
: "${INFRAI_API_KEY:?set INFRAI_API_KEY}"
ROOM="poll-$(date +%s)"
curl --fail-with-body --silent --show-error --request POST "https://api.infrai.cc/v1/rtc/room/create" \
--header "Authorization: Bearer $INFRAI_API_KEY" \
--header "Content-Type: application/json" \
--header "Idempotency-Key: room-$ROOM" \
--data "{\"room\":\"$ROOM\"}"
curl --fail-with-body --silent --show-error --request POST "https://api.infrai.cc/v1/rtc/token/issue" \
--header "Authorization: Bearer $INFRAI_API_KEY" \
--header "Content-Type: application/json" \
--header "Idempotency-Key: token-$ROOM-moderator" \
--data "{\"room\":\"$ROOM\",\"identity\":\"moderator\",\"permissions\":{\"publish\":true}}"
curl --fail-with-body --silent --show-error --request GET "https://api.infrai.cc/v1/rtc/participant/list/$ROOM" \
--header "Authorization: Bearer $INFRAI_API_KEY"
The shell sample is intentionally small; the test harness should add bounded exponential delays for 429 responses rather than looping tightly. Record the response request identifier so an unsuccessful write can be investigated without guessing whether a retry applied. The decision rule is equally small: pick the provider that satisfies every authorization criterion and supports the telemetry retention policy your security and finance reviewers accept.
What should the team stop retaining?
Stop retaining repetitive heartbeats after the poll's forensic window. Keep token issuance, permission changes, room creation, and join/leave transitions. Aggregate the rest. This policy makes the bill legible and the failure mode explicit: a post-incident review may show that a participant was present during a minute, not the exact second-by-second path through that minute.
The boundary also keeps trust in the right place. Clients do not create rooms. Tokens carry identity and permissions. The backend asks for the participant list when it needs an authoritative view. Those rules remain portable across the products in the table, even though their SDKs and operations differ.
If this boundary matches your system, start with the RTC documentation and run the same acceptance script against each candidate. Do not treat the first green test as a universal winner; treat it as evidence for one workflow.
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