Real engineering impact — documented as Problem → Solution → Outcome.
PerformancePerformanceArchitecture
US Compliance & Audit Platform · 2024Cut 3,500-Question Form Load from 14s to 4s by Rebuilding the Expression Engine
Problem
A compliance audit tool used SurveyJS to render forms with up to 3,500 questions and 2,000 conditional expressions. Every call to setAnswer triggered a full recursive expression cascade across the entire form — re-evaluating visibility and validation rules for every question on every keystroke. The result was a 14-second load that blocked auditors from beginning work.
Solution
• Batched answer mutations into a single atomic pass before triggering evaluation
• Deferred expression re-evaluation off the critical render path via async microtask queue
• Cached expression results so unchanged questions were never re-evaluated
• Coalesced DOM updates into one commit per batch cycle
Impact
Form load time dropped from 14 seconds to 4 seconds — a 71% reduction — across all 3,500-question forms. Auditors could begin entering data immediately. The expression evaluation engine was later adopted as the standard pattern for all new form builds on the platform.
sLoad time before
sLoad time after
%Reduction
+Questions handled
SurveyJSReactJavaScript
ReliabilityReliabilityPerformanceArchitecture
Indian Healthcare Data Platform · 2021Reduced Patient Data Upload Time by 90% with a Streaming Chunked Pipeline
Problem
A healthcare data platform needed to upload large patient GDS datasets into Firebase. Single-request payloads routinely hit Firebase's document-size and rate-limiting ceilings, causing uploads to fail silently mid-way. A full restart was the only recovery — meaning a 5-hour upload that failed at hour 4 had to begin again from zero.
Solution
• Replaced monolithic upload with a Node.js streaming pipeline
• Each chunk committed independently with exponential backoff on failure
• Dead-letter queue routed failed chunks for targeted retry — no full restarts
Impact
End-to-end upload time fell from 300 minutes to 30 minutes — a 90% reduction. Failed-chunk retries eliminated full-restart recovery entirely. The dead-letter queue provided an audit trail of every failure for compliance review.
minUpload time before
minUpload time after
%Reduction
Node.jsFirebaseStreamsJavaScript
PerformancePerformanceArchitecture
Canadian Paratransit Dispatch Platform · 2025Unfroze a Live Dispatch Dashboard for 10,000 Members Without Touching Ember
Problem
A paratransit dispatch platform built on Ember.js loaded 10,000 member records into a single computed property chain. Each record update cascaded through Ember's observer system, triggering full list re-renders. During mid-shift operations, the dashboard froze for 3–5 seconds per interaction — operators were unable to dispatch rides during critical windows.
Solution
• Embedded React at a single DOM mount point inside the existing Ember shell
• Rewrote member list as a windowed virtual list rendering only ~20 visible rows
• WebSocket stream fed updates directly into React state, bypassing Ember's observer graph
• Zero existing Ember code modified
Impact
Rendering throughput improved by 120% under peak load. Dashboard freezes were eliminated. The embedded React approach became the internal migration pattern for all high-churn views on the platform.
+%Render throughput
linesEmber code changed
ReactEmber.jsWebSocketsJavaScript
ArchitectureArchitecturePerformance
Canadian Government E-Governance Platform · 2022Reduced Tree Node Drag-and-Drop Freeze from 6s to Under 1s with a Linked List
Problem
A government form-builder used a deeply nested tree structure to represent form sections and fields. Drag-and-drop reordering triggered a jQuery recursive traversal of the entire tree to find the affected nodes and rebuild the structure. On forms with hundreds of nodes, every drop caused a 5–6 second UI freeze — making the builder unusable for large government forms.
Solution
• Replaced nested tree with a flat linked list using explicit parent/child/sibling pointers
• Insert and delete became O(1) pointer updates with no traversal
• Tree view derived from flat list at render time
Impact
Node drop response time fell from ~6 seconds to under 1 second — more than an 85% reduction. The builder was immediately usable on the largest government form templates in the system. The linked list data structure was adopted as the standard for all subsequent tree-based features.
~sDrop time before
<sDrop time after
>%Reduction
AngularJSjQueryJavaScript
PerformancePerformance
European Public Transit Provider · 2023Sped Up Route Map Rendering 40% with a Keyed Layer Diff
Problem
A public transit route planning tool rebuilt its entire Leaflet map — tearing down and recreating all layers — every time the user submitted a new route search, regardless of how much of the map had actually changed. On complex multi-stop searches, the teardown/rebuild cycle caused a noticeable visual flicker and added hundreds of milliseconds of render latency per query.
Solution
• Built a keyed diff layer comparing incoming route data against live map state
• Assigned stable keys to each marker, polyline, and popup
• Issued only the minimal create, update, or delete operations needed per render
Impact
Map render speed improved by 40% across typical route search workflows. Visual flicker on route changes was eliminated. The diff layer was extracted as a reusable Angular service adopted across three other map views in the product.
LeafletAngularTypeScriptRxJS
ArchitectureArchitectureReliability
US Compliance & Audit Platform · 2024Delivered 100% Offline Coverage for Air-Gapped Auditors with Zero App Rewrites
Problem
Compliance auditors frequently worked in air-gapped environments — government buildings and secure facilities with no internet access. Any connectivity loss caused active sessions to drop and in-progress audit data to be lost. With hundreds of network call sites scattered across the codebase, retrofitting each with offline-handling logic was not feasible.
Solution
• Service Worker interceptor captured all outbound requests when offline
• Persisted queued requests to IndexedDB for ordered replay on reconnect
• Zero existing request or API code modified
Impact
100% of audit sessions remained uninterrupted through connectivity loss. Data loss incidents dropped to zero. Zero lines of existing request or API code were changed, making the rollout risk-free.
%Offline coverage
linesExisting request code changed
ReactService WorkersIndexedDBPWA
PerformancePerformance
Algorithmic Trading Platform · 2019Eliminated Browser Memory Crashes on 10-Year Backtesting Data Loads
Problem
A backtesting tool allowed traders to visualise strategy performance across 10+ years of historical data. Fetching the full dataset in a single request routinely exhausted browser memory — particularly on mid-range machines — causing the tab to crash before the chart ever rendered. Users had no feedback during the long fetch and no recovery path on failure.
Solution
• Replaced the single fetch with a debounced 5-chunk sequential pipeline
• Chart rendered progressively as each chunk arrived
• Single-chunk failures retried in isolation — no full restarts
Impact
Browser memory crashes were eliminated entirely. Time-to-first-data dropped from a blank wait to seconds. Trader satisfaction with the backtesting tool increased measurably after the rollout.
Memory crashes
Chunks per load
ChartIQAngularRxJSTypeScript
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