Identity Verification
The KYC integration verifies identity before a user can list a vehicle or enter the protected purchase flow.
Back to Work
AutoAlly
A used-car marketplace designed around the hardest part of the transaction: giving buyers and sellers enough evidence, protection, and communication to move forward with confidence.
Next.jsNestJSPostgreSQLSocket.ioTailwind CSSEscrow APIKYC APITwilio Verify
Overview
Trust has to exist before the transaction
A vehicle marketplace is not only a catalogue. Buyers need confidence in the seller, the vehicle, and the payment path; sellers need qualified buyers and a clear route from offer to released funds.
AutoAlly turns those trust requirements into visible product states: identity-checked sellers, inspection-backed listings, protected escrow, messaging, delivery milestones, and a defined return window.
My work connected the public discovery experience with the operational surfaces behind it: search and listings, account verification, documents, real-time conversations, offers, and transaction state.
Timeline
4 months
Role
Full-Stack Developer
Tech Stack
- • Next.js + Tailwind CSS
- • NestJS API
- • PostgreSQL
- • Socket.io
- • Trustap Escrow API
- • KYC Verification API
- • Twilio Verify API
Platform Type
Marketplace Web Application
Product model
Three layers of marketplace trust
The experience is structured around the questions a buyer asks before committing: who is selling, what is being sold, and what protects the exchange?
01
Identity
Seller and buyer verification, ownership evidence, and visible trust states reduce ambiguity before a conversation begins.
02
Vehicle evidence
Inspection-backed listings, vehicle documents, history, specifications, and condition signals keep decisions evidence-led.
03
Transaction protection
Escrow, explicit milestones, communication history, disputes, and return handling make the exchange legible to both sides.
Live product
Trust signals stay attached to the vehicle
These current public screens show the system a buyer actually evaluates: searchable inventory, evidence on each listing, and clear protection states.
Marketplace inventory / 01
Evidence and protection are visible before the detail page
Vehicle cards combine price, condition, location, specifications, seller status, inspection availability, and escrow protection without turning the search result into a wall of badges.
Responsive discovery / 02
Search remains usable when every control has to stack
The mobile layout preserves the full search entry point and protection message instead of reducing the experience to a decorative hero.
Vehicle decision / 03
The detail surface moves from interest to due diligence
Specifications, documentation, seller context, and transaction actions sit within one decision path rather than separate product areas.
Operational surfaces
The marketplace continues after discovery
Listing creation, account operations, and vehicle documents give sellers and buyers the tools to move a real transaction forward after the first search.
Communication
Instant Messaging, Real-Time Updates
Socket.io powers real-time messaging so buyers and sellers can negotiate, ask questions, and close deals without delays.
Trust architecture
Protection is visible at every decision.
Each gate answers a different risk: who is acting, whether they can be reached, where the money is, and what evidence supports the vehicle.
Phone Verification
Twilio Verify adds phone ownership checks to account verification and high-risk transaction actions.
Escrow Payments
Trustap holds payment securely until both parties confirm the transaction is complete.
Document Verification
Buyers can verify vehicle documents and history before committing to purchase.
System architecture
Clear boundaries behind a complex exchange.
The platform separates public discovery, application workflows, live communication, and transaction data while keeping one coherent product model.
Next.js Frontend
Public discovery, account workflows, and responsive transaction surfaces share one component language.
NestJS API
A modular TypeScript API coordinating authentication, listings, verification providers, escrow state, messaging, and notifications.
Real-Time WebSockets
Socket.io delivers conversations and transaction updates while the durable record remains independent.
PostgreSQL Database
Relational models preserve ownership, listing, conversation, verification, and transaction relationships.
Delivered product
One system across the full exchange
The value is in the connection between discovery, evidence, communication, and transaction state—not in a long list of isolated marketplace features.
Discovery
Search, filters, saved vehicles, categories, and price alerts
Evidence
Seller identity, ownership, inspections, and vehicle documents
Exchange
Messaging, offers, escrow milestones, delivery, and disputes
Operations
Listing management, account state, notifications, and audit history
Engineering Challenges
The hard parts I solved
Real-time messaging that doesn't melt the database
Solution · Socket.io for live transport, Postgres for persistence (writes batched + async), Redis pub/sub for fan-out across instances. Message read state lives in a separate fast table to avoid contention with the main message log.
Outcome · Conversation history remains durable while live delivery can scale independently from the main message record.
Escrow flow that protects both sides
Solution · Multi-step state machine with explicit transitions (pending → buyer-funded → seller-shipped → buyer-confirmed → released). All transitions logged immutably; disputes pause the state and route to admin review with the full audit trail.
Outcome · Every transaction has an explicit state, a visible next action, and an audit trail for support or dispute review.
KYC + listing verification at scale
Solution · Automated VIN check + ID verification + document upload at signup; verified-seller badge on listings; flag-and-review workflow for buyer reports with priority queue for admins.
Outcome · Verification decisions surface consistently across listings, accounts, and review tools instead of living in a hidden back-office check.
Building a marketplace?
I take on senior contract work for marketplaces, real-time systems, and trust-and-safety infrastructure.