Trial killers
Lag, conflicts, and room collapses blocked enterprise closes.
SK Assist
· AISatyakabir Assistant
Satyakabir Technologies
Technology engineering · Digital transformation
Work · Case study
Sub-10ms collaboration that holds at half a million concurrent users
500K
concurrent users
<10ms
local edit feel
99.95%
session uptime
6 mo
to enterprise GA
Case study
We engineered a real-time collaboration fabric — WebRTC mesh, conflict-free document sync, and end-to-end encryption — so 500K concurrent users could co-edit without the lag and dropouts that were killing enterprise deals.
Challenge
Enterprise buyers rejected the product in trials: presence flickered, edits collided, and video rooms collapsed under modest concurrency. The team had shipped features faster than the realtime substrate could carry them.
Solution
We redesigned the sync and media plane: CRDT-backed documents, selective forwarding and mesh for media, E2E encryption with recoverable enterprise keys, and load tests that mirrored real multi-region usage — then shipped with SRE rituals the client could run.
How we framed the work
Lag, conflicts, and room collapses blocked enterprise closes.
Document sync and media engineered as separate reliability domains.
Concurrency tests mirrored real multi-region buyer scenarios.
E2E encryption with enterprise recovery — not security theatre.
Engagement arc
5 stages · operator-owned handoffs
Diagnose
Failure modes under load
Reshape
Sync + media planes
Harden
E2E + recovery paths
Prove
Multi-region load & chaos
Enable
SRE + support playbooks
Cadence
Reproduce lag, conflict, and room death under load.
CRDT plane, presence, offline recovery.
SFU/mesh, encryption, enterprise recovery.
Multi-region chaos, SRE transfer, enterprise GA.
01 · Context
The product looked complete in demos of five people. At fifty, presence lied. At a few hundred, edits fought and rooms dropped. Sales needed a substrate that survived enterprise trials — not another UI polish sprint.
02 · Architecture
Documents moved to CRDT-backed sync with clear authority regions and offline catch-up. Media used selective forwarding with mesh fallbacks for small rooms. Encryption protected payloads; enterprise recovery was designed with security, not bolted on. Observability treated latency histograms and reconnect storms as first-class product metrics.
03 · Delivery
We built a harness that replayed concurrent editing and call patterns from anonymized production shapes. Each wave had a kill switch. UX work focused on conflict visibility and reconnect honesty so users trusted the system when the network did not.
04 · Security
Key hierarchies supported device loss and admin recovery under policy. Servers minimized plaintext exposure. Threat models covered room hijack, replay, and insider metadata abuse — with fixes tracked as product work, not audit season panic.
05 · Outcomes
The stack sustained 500K concurrent users in staged peak tests. Local edit feel stayed under 10ms on healthy links. Session uptime for instrumented enterprise cohorts hit 99.95%. Win-rate on technical trials improved as lag and drop complaints fell out of deal reviews.
06 · Transfer
SRE playbooks, dashboards, and on-call shadows transferred ownership. We documented failure modes we had already seen so the next outage would not be a first contact.
01
CRDT document sync with offline recovery
02
Media SFU/mesh with adaptive bitrate
03
Enterprise E2E key recovery flows
04
Presence and awareness at scale
05
Chaos and concurrency test harness
Edge presence + regional sync authorities
Media plane separate from document plane
Encrypted payloads; server sees metadata only where required
Progressive reconnect and conflict visualization
From the engagement
Sub-10ms collaboration that holds at half a million concurrent users
Stack & standards
“Our enterprise trials stopped failing on the substrate. That changed the sales conversation overnight.”
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