Senior Frontend / Product Engineer

Elchai Group; United Arab Emirates; Remote; AED 248,000 - 413,000; Part time

Job summary

Elchai Group is seeking a freelance engineer to implement a browser-side switch boundary and ensure safe context switching for a governed business-assistant interface. This role focuses on real-time voice UX, WebSocket audio interfaces, and accessibility considerations, with remote work by agreement.

You will deliver milestones M0–M4, verify stop-before-switch, suppress stale audio, and provide repeatable demos and handovers.

Qualifications

• Proficient in asynchronous JavaScript/TypeScript development.
• Experience with real-time audio and WebSocket interfaces.
• Familiarity with race/cancellation handling in async contexts.
• Testing keyboard focus and assistive technology.
• Maintaining and extending existing frontend code.

Responsibilities

• Implement stop-before-switch boundary and context-switch control.
• Ensure stale audio/text does not render after context changes.
• Create minimal view/error states for failed switches.
• Provide repeatable demos and clear handover artifacts.

Skills

Async JS/TS

Real-time audio interfaces

WebSocket

Race cancellation

Keyboard/focus testing

Tools

Web Audio API

Browser debugging

Job description

Real-time voice UX, source evidence and accessible web interfaces | Freelance

Elchai Group | Bounded contract opportunity | Remote working by agreement

Elchai is developing New Pulse as the authenticated human interface to a governed business-assistant architecture. Selection and any paid work remain subject to approval. This is not an unpaid internship or an invitation to start work before a contract.

Safe branch switching and simulated voice cancellation

Implement one browser-side switch boundary: stop listening/speaking before issuing a context-switch request; discard late old-context audio/text/responses; render only the newly authorized context or a safe error state.

This package excludes a whole frontend rewrite, live speech-provider setup, backend permissions and a new orchestration system.

We agree the exact scope, baseline or input register, interfaces, tests, reviewer, fees and availability before work. For development, the assignment uses an isolated sandbox and synthetic data; internal owners retain architecture, security, independent QA and release authority. For research/commercial work, only authorized public-source research and synthetic exercises are included unless separately stated.

Milestones and smaller deliverables

M0: Freeze switch and display contract (client readiness gate; no free candidate deliverable).

M0.1: verify existing behavior/baseline. M0.2: agree fixture/events/design subset. M0.3: freeze tests and approve start.

Required evidence: Baseline and manifest; state/event table; browser cases; no-duplication record; review slots.

Pass condition: The client confirms the agreed package, necessary dependencies, named reviewer and permission to start. A quote or interview does not require unpaid implementation.

M1: Implement only the switch boundary (8-12 focused execution hours).

M1.1: fixtures and adapter, 2-4 h. M1.2: stop/cancel/event ordering, 4 h. M1.3: minimal view/error states, 2-4 h.

Required evidence: Components and three checkpoint handovers; event traces; authorized/failed switch demo.

Pass condition: Audio stops first and context changes only through the approved response; no old-context rendering.

M2: Test races and accessibility (6-10 focused execution hours).

M2.1: functional/denial tests, 2-4 h. M2.2: late-event/reconnect stress, 2-4 h. M2.3: focused keyboard/layout checks, 2 h.

Required evidence: FE-01 to FE-08 results, browser traces, seeds, videos/screenshots where useful and defects.

Pass condition: Required cases pass on the agreed browsers; no stale data/audio or access-boundary defect.

M3: Independent demonstration and acceptance (2-6 focused execution hours).

M3.1: independent rerun. M3.2: corrections/retest, 2-6 h. M3.3: freeze candidate and limits.

Required evidence: Repeatable demo; reviewer result; rollback and cold-start record.

Pass condition: Accepted exact component version; fixture-only limits recorded; no backend/full-platform claim.

M4: Transfer and estimate next UI slice (2-4 focused documentation/reporting hours).

M4.1: complete component/API handover. M4.2: actuals and next estimate.

Required evidence: Setup/test commands, event contract, known gaps, actual work/wait and remaining interface tasks.

Pass condition: Replacement reproduces the selected checks and can identify the next task; further work stays unapproved.

The hour ranges are initial planning guides, not deadlines or accepted prices. Quote your own effort and fee by milestone, including documentation, correction assumptions and availability. Internal approval and review time is separate; waiting for those decisions is not concealed as development work.

Verification focus

Demonstrate stop-before-switch, stale audio/text suppression, denied/failed switches, reconnect races and keyboard/focus behavior. The proposed repeated test includes 50 listening-state switches and 50 speaking-state switches per run, plus delayed-event scenarios. This does not claim backend isolation or full-product accessibility certification.

Handover at every checkpoint

Deliver editable files, the exact current version, setup/test commands or research method, interface/source definitions, known defects, accepted versus unfinished work and the next task. Another authorized contributor must be able to reproduce the checkpoint without relying on your private account or undocumented knowledge. Final handover includes a clean-start reproduction and measured hours/corrections. We do not request confidential material from former clients.

Experience evidence

Relevant skills: Async JavaScript/TypeScript; real-time/WebSocket/audio interfaces; race cancellation; keyboard/focus and assistive technology testing; maintaining existing code.

Provide two relevant shipped-work or redacted project examples and your precise contribution; answer this question: Show how you prevented a late response or decoded audio clip from rendering after a user changed context. Show how you tested the race.

Include your proposed milestone fees, currency, availability, working-time overlap, assumptions, exclusions and any subcontracting. We do not request free test work.