Full-stack engineer who shipped a production platform from auth to payments in 5 months.

~/zayren
$ whoami
full-stack engineer · solo builder · production-ready systems
shipped: multiple production platforms · live · real users
featured projects

Handleasy

live

AI receptionist platform built as a full production product for service businesses — handling inbound calls, lead capture, scheduling flows, and customer interactions.

Full-stack product · AI voice workflows · business onboarding · call handling · scheduling · production deployment

LootLust

100+ active users

Two-sided digital marketplace — built solo from auth to payments. Live in production with real users.

Real-time messaging · token-based escrow · Stripe & crypto payments · OAuth integration · referral system · admin dashboard
tech stack
React Firebase Firestore Cloud Functions Stripe SendGrid Firebase Auth HTML/CSS/JS TypeScript Next.js 14 Tailwind CSS PostgreSQL Jest Cypress WebSockets Socket.io Sentry Datadog Algolia
core competencies

Data Modeling & Schema Design

I design data models that hold up under real usage. 40+ collection Firestore schemas, subcollection chunking for scale, and relationships that make sense.

FirestoreSchema DesignSubcollections

Real-Time Systems

Live chat, presence, and instant updates using Firestore listeners. I tune real-time features to stay responsive without spiking read costs as usage grows.

onSnapshotWebSocketsPresence

Payments & Financial Logic

Integrated Stripe and crypto payments with retry logic and exponential backoff. I build transaction flows that recover gracefully instead of silently failing.

StripeWebhooksCrypto

Third-Party API Integration

OAuth, rate limiting, IP-blocking workarounds — I handle the quirks of external APIs so your product stays resilient.

OAuthRate LimitingRetry Logic

Performance Engineering

Lazy-loaded images, debounced search, infinite scroll, and caching layers that cut load times without overcomplicating the stack.

CachingLazy LoadingInfinite Scroll

Media Pipelines

Drag-and-drop uploads with client-side resizing and thumbnail generation — keeping storage and bandwidth costs predictable.

File UploadThumbnailsCloud Storage

Security & Access Control

Role-based Firestore security rules that give every user exactly the data they're allowed to see — and nothing more.

Security RulesRBACAuthentication

Transactional Integrity

Firestore transactions and batched writes to keep multi-step operations consistent — even when individual steps fail midway.

runTransactionBatched WritesConsistency

Admin & Moderation Tooling

Internal dashboards for reports, bans, and flagged content — backed by analytics so moderation decisions aren't made blind.

Admin UIModerationAnalytics

TypeScript & Type Safety

100% TypeScript codebases with strict mode — catching errors at compile time and shipping zero type-related runtime bugs.

TypeScriptGenericsUnion Types

Cloud Architecture

Firebase and AWS services including EC2 for compute, S3 for storage, RDS for relational data, and Lambda for serverless functions.

AWSEC2S3RDS

Testing & Quality Assurance

Unit tests with Jest, integration tests for API endpoints, and E2E tests with Cypress — maintaining 80%+ coverage on critical paths.

JestCypressReact Testing Library

Monitoring & Observability

Error tracking with Sentry, performance monitoring with Datadog, and structured logging to reduce mean time to resolution.

SentryDatadogLogging

Search & Discovery

Algolia integration for fast, typo-tolerant search across large datasets — with faceted filtering and relevance tuning.

AlgoliaSearchFiltering

Relational Databases

PostgreSQL with Prisma ORM for complex queries, reporting, and transactional integrity across relational data.

PostgreSQLPrismaSQL
how I build
1

Data model first

Schema before code. Every collection and relationship gets mapped out before a single UI component exists — reworking a data model later is expensive.

2

Auth early

Identity touches everything — permissions, ownership, security rules. I build it in from day one to avoid retrofitting access control later.

3

Core transaction flows first

Get the money — or the trade, or the trust mechanic — moving before anything else. This is the part that has to be correct, so I build and stress-test it first.

4

Real-time features on top

Chat, presence, live updates — this is what makes a product feel alive instead of static. Layered on top of a working data model and auth system.

5

Polish & performance

Caching, lazy loading, and security rules come last — once the product works end to end, this is what makes it fast and safe to launch.

full-stack architecture
end-to-end request flow
Browser (React + Next.js)
TypeScript · Tailwind · Zustand · React Query
Firebase Auth
email/password + OAuth providers · JWT · RBAC
Firestore + PostgreSQL
Firestore for real-time · PostgreSQL for reporting
Cloud Functions + Express API
webhooks · business logic · REST endpoints
Stripe
payments · subscriptions · idempotent webhooks
SendGrid
email notifications · transactional templates
my development rhythm
Phase 1 Planning & Foundation — schema design, tech selection, auth & onboarding, core data model
Phase 2 Core Functionality — real-time systems, transactional flows, payment integration with retry logic and webhooks
Phase 3 Performance & Security — caching, lazy loading, security rules, role-based access, production hardening
Phase 4 Launch & Iterate — monitoring, feedback loops, user-driven improvements, scaling as usage grows
about

I'm a full-stack engineer who likes the parts of a build most people avoid: the data model that has to hold up under real usage, the security rules that quietly prevent a breach, the edge case in a payment flow that only shows up in production.

I'm looking for a remote engineering role or contract where I can bring that same ownership to a team's product — someone who can take a feature from idea to shipped without needing much hand-holding in between.

Currently looking for: remote full-stack or backend engineering roles, contract or full-time. I'm available to start.

get in touch

Let's talk about the role

Send a quick message — I reply within a couple hours.

or email directly at Zay9dev@gmail.com