Full-Stack Dev for Live Multi-Vendor Marketplace -- 2

# Full-Stack Developer Needed – Existing Multi-Vendor Marketplace (4–8 Week Project)

We are seeking an experienced, dependable full-stack developer to **debug, repair, complete, and stabilize an existing live multi-vendor e-commerce marketplace.**

**This is NOT a new website build or a project requiring development from scratch.** HairGrab is already operational, with an established codebase, database, seller portal, admin dashboard, payment integrations, mobile application, and partially completed features.

The selected developer will take over existing development work, troubleshoot outstanding issues, complete unfinished functionality, and ensure systems operate reliably.

**Project Duration:** Approximately 4–8 weeks, with the possibility of additional work.

**Current Tech Stack:**
- React, Remix, TypeScript
- Node.js, PostgreSQL, Prisma
- Railway, GitHub
- Stripe Connect
- Expo / React Native (mobile experience is a plus)

## Scope of Work

The project consists of a prioritized backlog of existing bugs, incomplete integrations, unfinished functionality, and production issues.

**All major systems and features are already built, partially implemented, or currently being worked on. The expectation is to review, debug, complete, and improve existing work—not replace functioning systems or begin unnecessary new development.**

### Critical / Immediate Priorities

**1. Complete Multi-Platform Inventory Synchronization – TOP PRIORITY**

Inventory synchronization development will already be underway before the selected developer begins.

The developer's responsibility is to **take over, troubleshoot, complete, test, and deploy the existing inventory synchronization work**, ensuring reliable inventory updates between HairGrab and supported external selling platforms.

The long-term system should accommodate major e-commerce platforms, potentially including:

- Shopify
- WooCommerce
- BigCommerce
- Wix
- Squarespace
- Square Online
- Ecwid
- Shift4Shop
- Other platforms with suitable integration capabilities

**Key responsibilities:**
- Review and understand inventory synchronization work already completed.
- Identify and repair incomplete or malfunctioning integration components.
- Finish existing API connections, webhook handling, and synchronization workflows.
- Complete two-way inventory synchronization where supported.
- Verify accurate product-level and variant-level inventory updates.
- Debug SKU mapping, product matching, and inventory reconciliation issues.
- Complete authentication, error handling, retry mechanisms, and monitoring functionality where already implemented or planned.
- Finish seller-facing connection status and synchronization controls.
- Ensure inventory remains consistent between HairGrab, connected external stores, and HairGrab-hosted seller storefronts.
- Test completed integrations and resolve synchronization errors before production deployment.

**Important:** This assignment is to finish an inventory synchronization system already in development, not build an entirely new integration platform.

Existing architecture and code should be reused wherever practical. Additional platform integrations will be prioritized based on the current development status, available budget, and timeline.

Not every listed platform must be completed during this engagement.

**2. Inventory Protection and Checkout Reliability**
- Diagnose and resolve existing inventory overselling issues.
- Repair stock validation and inventory deduction problems during checkout.
- Verify accurate stock restoration following eligible refunds and cancellations.
- Troubleshoot checkout errors affecting live transactions.
- Test and stabilize existing checkout and inventory workflows.

**3. Stripe Connect and Payment Reliability**
- Debug existing seller transfer and settlement issues.
- Repair partial refund, chargeback, and payment reconciliation problems.
- Verify existing commission calculations and seller payouts.
- Resolve payment webhook and transaction-processing errors.
- Test and stabilize current payment functionality without rebuilding the payment system.

**4. Production Stability**
- Identify and resolve critical bugs affecting marketplace operations.
- Troubleshoot existing functionality that is incomplete or unreliable.
- Fix regressions without disrupting working features.
- Protect live seller data, customer information, inventory, and financial transactions.

### High-Priority Tasks

- **Bulk Product Management:** Finish debugging and repairing existing bulk editing, publishing, and archiving functionality.
- **Seller and Admin Dashboards:** Correct outstanding issues, complete unfinished controls, and improve existing workflows.
- **Giveaway Management:** Finish and debug existing giveaway campaigns, entry tracking, milestone rules, and administrative controls.
- **Mobile Application:** Resolve outstanding bugs, complete remaining submission requirements, and assist with App Store deployment as needed.
- **Seller Onboarding:** Troubleshoot and complete existing seller registration, storefront setup, product management, and onboarding functionality.
- **Hosted Seller Storefronts:** Complete and debug existing connections between HairGrab marketplace storefronts and independently hosted seller websites, ensuring shared product and inventory updates while maintaining separate payment workflows where applicable.

### Additional Tasks

- Debug and improve existing product categories, filters, and merchandising.
- Complete unfinished UI/UX improvements already identified.
- Repair and improve existing administrative tools.
- Address remaining operational bugs and incomplete features.
- Complete other prioritized backlog items within the agreed project timeline and budget.

**These are existing development tasks, repairs, and completion items—not requests to design and build new systems from the ground up.**

## Requirements

- Strong experience troubleshooting and maintaining existing production applications.
- Proven React, TypeScript, PostgreSQL, and Prisma experience.
- Experience completing or repairing inventory synchronization integrations using APIs and webhooks.
- Experience with Stripe Connect, including connected accounts, transfers, refunds, and webhooks.
- Familiarity with Remix, Railway, GitHub, and production deployments.
- Ability to understand unfamiliar codebases and continue development started by others.
- Strong debugging, testing, and documentation skills.
- Ability to identify root causes rather than repeatedly applying temporary fixes.
- Ability to work independently and deliver results without constant supervision.
- Experience with multi-vendor marketplaces or e-commerce platforms strongly preferred.

**We are specifically looking for someone skilled at finishing and stabilizing existing software—not someone whose primary experience is starting new projects.**

## Communication Expectations

**Reliable communication and consistent progress are essential.**

We expect:
- Acknowledgment of messages within four business hours during agreed working hours.
- Regular, meaningful progress updates.
- Clear reporting of completed tasks, remaining issues, and blockers.
- Advance notice of delays or scheduling conflicts.
- Consistent follow-through on agreed milestones.
- Availability to address urgent production issues within agreed working hours.

We do not require 24/7 availability. However, we do require accountability, responsiveness, and dependable communication.

**We are not looking for a developer who takes on the project but repeatedly delays work because of competing commitments.**

## Project Structure
Budget is negotiable based on experience, availability, and the work required. Developers are encouraged to submit competitive milestone-based proposals with estimated costs and completion timelines.

We prefer milestone-based delivery, with critical issues addressed first.

The selected developer will begin with a short paid technical assessment to review the existing codebase, confirm the status of work already completed, identify outstanding issues, and establish realistic completion milestones.

The assessment should focus on understanding and finishing existing development—not proposing unnecessary rebuilds.

**Project expectations:**
- Prioritize critical fixes and unfinished functionality.
- Work from the existing codebase and development backlog.
- Preserve working features and avoid unnecessary code changes.
- Test all repairs and completed features before deployment.
- Protect existing marketplace functionality, seller data, and payment operations.
- Provide clear documentation of changes and testing results.
- Deliver completed, working milestones rather than extended periods of investigation without results.

Project priorities may be adjusted based on urgent operational needs.

## Please Include in Your Proposal

1. Examples of existing applications or marketplaces you have repaired, completed, or maintained.
2. Your experience troubleshooting or completing inventory synchronization integrations.
3. Which e-commerce platforms you have personally integrated using APIs or webhooks.
4. Your experience with Remix, Prisma, Railway, and Stripe Connect.
5. Your actual availability and weekly working capacity over the next 4–8 weeks.
6. Your approach to taking over and completing partially developed functionality.
7. Your estimated hourly rate or milestone-based pricing.
8. How quickly you can begin and deliver your first completed milestone.

**We are looking for a reliable, experienced developer who can step into an existing codebase, resolve outstanding problems, finish development already in progress, and deliver measurable improvements quickly.**

**HairGrab does not need to be rebuilt. It needs to be completed, debugged, tested, and stabilized.**