vahid.

Vahid Keshavarz Senior software engineer

I build marketplaces, payment systems, and AI features, with hands-on ownership from architecture to the final interaction.

Selected work View CV
Industrial monitoring project with vibration analysis and colorful frequency signals
Marketplace admin project with order management and sales analytics
Agate Slab website with expressive amber, ivory, and charcoal layers of natural stone
Agate Art storefront presenting a sculptural black stone vessel and white orchid
Marketplace product detail page with product photography, seller information, and purchase controls
Mobile AI concierge showing a diamond conversation and live product recommendations

7+ years turning complex requirements into software people use.

Based in IstanbulOpen to remote roles & relocation
GitHub LinkedIn

The work, up close.

Different products. The same attention to how the interface, the data, and the system work together.

GEMGEM / Commerce & payments

A marketplace.
The whole ecosystem.

Hands-on engineering and technical leadership across a live jewelry marketplace, from buyer experience to production operations.

10,000+active listings

Four marketsmulti-currency checkout

Senior engineer → Tech Leadpromoted after one year

Funnel analytics PostHogGA4

  1. view_item
  2. begin_checkout
  3. add_payment_info
  4. purchase
Marketplace product page with protected payment, purchase and offer actions
AI concierge AI concierge asking about certification and shape, then recommending GIA-certified round diamonds under $1,000

Monitoring & infrastructure

  • SentryErrors, release health
  • CloudWatchLogs, metrics, alarms
  • AWSDeployment, infrastructure

Checkout

  • Stripe Card, Apple Pay
  • PayPal Express
  • Bitcoin Crypto

Paid · funds held until delivery

My contribution

I joined GEMGEM as a Senior Software Engineer in January 2024 and was promoted to Technical Team Lead in January 2025. I still own hands-on architecture and feature delivery alongside planning, reviews, and releases.

Across the stack

Search, payment routing, buyer and seller tools, frontend migration, applied AI, security, and AWS operations. My work connects the customer experience to the systems behind it.

Laravel / Vue / Nuxt / Elasticsearch / Redis / AWS

What changed.

Faster search. A stronger frontend. A more discoverable product.

Elasticsearch search latency
~10s<400ms

Query, index-mapping, and caching improvements.

Lighthouse score
~2590+

Frontend migration and performance work, alongside Core Web Vitals improvements.

SEO health score
590+

Technical SEO improvements and expanded indexable content.

Behind the results.

Explore the work across the product.

Performance & discoverySearch, uploads, frontend & SEO
  • Search that responds. Refactored Elasticsearch queries, index mappings, and caching to reduce latency from about 10 seconds to under 400 milliseconds.
  • Uploads without the wait. Removed a separate roughly 10-second upload bottleneck by moving heavy file processing to asynchronous jobs.
  • A modern frontend foundation. Led the Nuxt 2-to-3 migration, delivered PWA capabilities, and improved frontend performance and Core Web Vitals.
  • More of the catalog discoverable. Added approximately 7,000 valid indexed pages through the migration and SEO work.
Payments & checkoutFour currencies, multiple payment providers
  • Multi-currency payment integrations. Integrated Stripe, PayPal, and CoinGate across USD, HKD, INR, and AUD, including cryptocurrency payments.
  • Payment flows built for recovery. Implemented webhooks, idempotency, and payment-failure recovery so retries and provider events could be handled safely.
  • The marketplace money lifecycle. Built seller onboarding and payouts, refund handling, and the buyer-to-order workflows connecting checkout to operations.
Applied AI & operationsProduct discovery, staff tools & reviewed content
  • A production shopping concierge. Turned natural-language buyer intent into structured diamond searches and live recommendations, with retrieval-grounded policy answers and human handoff. Explore the concierge
  • Controlled access to operational tools. Built an authenticated MCP interface for authorized staff to query order data and perform controlled actions.
  • AI content with human ownership. Shipped generated listing content and product-page verdicts with mandatory human review.
Security & productionAccess controls, cloud delivery & incident response
  • Stronger application boundaries. Encrypted sensitive data, introduced MFA, and tightened authorization and least-privilege access.
  • Ownership beyond deployment. Improved reliability across AWS ECS, EC2, RDS, S3, and CloudWatch through monitoring, automated CI/CD, release management, and incident response.
  • Better context during incidents. Introduced AI-assisted development and incident-triage workflows connecting AWS, Cloudflare, Sentry, alerts, and application logs for root-cause investigation and P0 response.
Technical leadershipArchitecture, weekly releases & mentoring
  • Technical direction with hands-on delivery. Promoted after one year to lead a cross-functional team while continuing to own architecture and implementation.
  • A consistent delivery rhythm. Owned sprint planning, technical design, code review, and weekly releases.
  • Engineers who can grow with the product. Mentored 10+ engineers, gave constructive design and PR feedback, and conducted technical interviews supporting hiring decisions.
Marketplace case study Admin platform case study

Applied AI

A conversation.
Connected to the product.

A shopping concierge that turns buyer intent into inventory searches and useful recommendations.

AI conciergeAutomated shopping assistant

I’m proposing next month! A grand, tops.

Congratulations! What’s your partner’s style?

Classic, nothing flashy.

A round stone suits that. Want a certificate?

Yes, one I can trust.

Three classic round picks for your proposal, all GIA certified and under $1,000.

  • GIA0.74 ct roundD color, SI2, Excellent cut$979
  • GIA0.63 ct roundF color, VS1, Excellent cut$943
  • GIA0.60 ct roundG color, VS2, Excellent cut$889
Ask about diamonds, value, or certification

Behind the replyRuns automatically

  1. 1 · AI orchestrationUnderstands the request

    Round GIA-certified Under $1,000 Proposal

    Next step: search for diamonds

  2. 2 · Tool callChooses the right tool

    Only approved tools can run.

    • Search diamonds
    • Look up policies
    • Call an expert

  3. 3 · InventorySearches live listings

    From every listing down to what fits.

    • Round
    • GIA
    • Under $1,000

  4. 4 · ResultsFinds the matches

    Three diamonds fit the request.

    • 0.74 ct round$979
    • 0.63 ct round$943
    • 0.60 ct round$889

  5. 5 · Eval checkChecks the answer

    • Round
    • GIA-certified
    • Under $1,000

    Good enough

    If not, it tries again.

  6. 6 · Format replyWrites the reply

    A short answer plus product cards.

My contribution

I designed and shipped the production concierge: the chat experience, structured inventory search, retrieval-grounded policy answers, and expert handoff.

Built for production

Input validation, request limits, and controlled tool access make the product usable beyond a demo.

Nuxt / TypeScript / RAG / LLM APIs

Case study

Real-time systems

From sensor signals
to operator decisions.

Industrial monitoring software that turns continuous vibration data into a view of equipment health.

Vibration analysis & equipment health

My contribution

I designed the high-frequency ingestion architecture, built sensor-data pipelines and time-series storage, and developed live dashboards and early-warning signal logic.

The engineering

Protocol handling, real-time messaging, and storage shaped around actual analysis patterns, connecting backend reliability to an operator’s daily workflow.

Real-time ingestion / Sensor protocols / Time-series data

Case study

A different kind of detail.

Client work where frontend craft, product presentation, and independent delivery come together.

Agate Art storefront with sculptural stone objects and considered typography

Agate Art

Art commerce, product discovery, and catalog UX.
Frontend & commerce delivery
Agate Slab product showcase with a close-up of natural stone

Agate Slab

A material-led product showcase and inquiry journey.
Custom frontend & motion
AU Insurance business website and service presentation

AU Insurance

Service clarity, a maintainable CMS, and direct contact paths.
WordPress & end-to-end delivery

I care about
the whole thing.

How it feels to use. How the data moves. What happens when a payment fails. And how the next engineer makes sense of it.

I’m a hands-on senior software engineer with 7+ years across marketplaces, SaaS, and real-time systems. My strongest work sits where backend complexity meets a clear user experience.

Technical leadership hasn’t taken me away from the code. I still design the architecture, build features, review changes, and stay close to production.

Metisix is the engineering practice behind this site. This page brings together my personal contributions across employment and client projects.

Build

PHP / Laravel
TypeScript / Node.js / NestJS
Vue / Nuxt / React

Operate

MySQL / PostgreSQL / Redis
Elasticsearch / AWS / Docker
CI/CD / Cloudflare / Sentry

View CV

A few more views of the work.

Marketplace browsing interface AI concierge product recommendations Industrial monitoring workspace Agate Art product presentation Agate Slab stone presentation

Project preview