Key takeaways
- The TURN relay allowance for Zenden Pro increases from 50 GB to 100 GB per month
- The cap applies only to relayed fallback traffic — direct P2P transfers are unlimited in both tiers
- Relay kicks in automatically when direct P2P cannot connect: mobile hotspots, carrier NAT, iCloud Private Relay
- Most users do not consume meaningful relay quota; the cap exists because TURN traffic has real infrastructure costs
- No action required — existing Pro subscribers get the higher allowance immediately
Zenden Pro includes TURN relay — a fallback path that routes encrypted transfer traffic through intermediary servers when a direct device-to-device connection can't be established. That relay has always had a monthly allowance. Today the allowance increases from 50 GB to 100 GB per month.
Direct P2P transfers are unaffected. They were unlimited before this change and remain unlimited. The cap applies only to bytes that travel through the relay.
Why relay traffic costs money
TURN relay works by routing your encrypted transfer through a server when direct P2P fails. That server consumes bandwidth proportional to the data volume transferred. Unlike signaling — which exchanges only a few kilobytes of connection metadata — relay bandwidth scales directly with file size and transfer frequency. Operating those servers at low latency across the network conditions where direct P2P fails is the primary recurring infrastructure cost for Zenden Pro.
Direct P2P, by contrast, costs nothing to carry once the connection is established. The files travel from your machine directly to the recipient's browser without passing through any server.
What changed and why 100 GB, not 50
The previous relay allowance was 50 GB per month. That figure was set conservatively before we had real usage data. After running Zenden Pro through its first months, the pattern became clear: most sessions complete via direct P2P without consuming any relay quota, but users doing high-volume work — sending large media archives or running transfers from mobile connections regularly — were hitting the 50 GB ceiling.
100 GB is the figure that accommodates that usage pattern without requiring per-user overage tracking. It is a meaningful increase for power users while remaining grounded in what the infrastructure can sustain at the current subscription price.
100 GB
Relay allowance per month
Applies to TURN fallback traffic only. Direct P2P is unlimited.
What counts toward the cap (and what doesn't)
Only bytes that travel through the TURN relay count toward the 100 GB. A transfer that completes peer-to-peer — the path for most sessions on home broadband, office Wi-Fi, and wired connections — consumes zero relay quota regardless of file size. The cap is per billing period, not per session or per day. It resets at the start of each billing cycle.
Which network conditions trigger relay
Three scenarios reliably force relay use. First, mobile hotspots: tethered connections often sit behind carrier-grade NAT where the phone's cellular IP is shared with thousands of other subscribers, making inbound P2P connections impossible. Second, symmetric NAT environments common in enterprise and hotel networks, where the NAT mapping changes with each new connection attempt. Third, iCloud Private Relay, which masks the real IP address and routes traffic through Apple's proxy, preventing STUN from discovering a usable public address.
Outside these scenarios, STUN traversal succeeds and relay is not used.
What about the recipient's network?
The relay path is selected based on whether either end of the connection fails to establish direct P2P — it does not require both sides to be on a restricted network. A sender on a normal broadband connection can still end up on relay if the recipient is behind iCloud Private Relay or symmetric NAT.
No action required
Existing Pro subscribers receive the higher allowance as of today. There is no plan change, no new billing event, and no setting to update. The allowance resets on your normal billing date.
If you are on the Free tier and need relay coverage for transfers from restricted networks, Zenden Pro is $8/month or $80/year.
