Phoenix - Your AI AssistantSenior Full-Stack Developer for Premium Marketplace Platform
- Posted:
- Proposals: 45
- Remote
- #4518739
- Open for Proposals
Mumbai 
Description
Experience Level: Expert
Estimated project duration: 1 - 6 months
We are developing the Pre-Launch MVP of a new digital marketplace for pre-owned and high-value goods and are looking for an experienced, hands-on Senior Full-Stack Developer / Technical Lead to review the existing specification and potentially build the MVP.
This is not a standard e-commerce website or simple listings marketplace. The product includes custom buyer/seller workflows, structured buyer demand, seller inventory and supply connectivity, matching, private inventory, progressive item readiness, communications, notifications and administration.
The scope is the Pre-Launch MVP — NOT the complete future Commercial Launch platform.
The MVP will operate with real users, buyer demand, sellers and real supply to validate the marketplace before commercial transactions are activated.
Pre-Launch MVP
The MVP will include:
• Buyer and seller onboarding
• Structured and persistent buyer search/demand workflows
• Seller inventory and supply connectivity
• Manual and bulk inventory ingestion
• Private/hidden inventory
• Configurable, category-specific item information
• Progressive item-data completion
• Demand-to-supply matching
• Seller activation/confirmation when relevant demand exists
• Buyer-visible relevant opportunities
• Item condition information, photos/evidence
• Communications and meaningful notifications
• Buyer/seller account areas
• Admin and operational controls
Detailed workflows and business rules are already documented and will be shared with shortlisted candidates.
Technical Direction
Preferred stack:
Next.js / React / TypeScript
Supabase / PostgreSQL
API-based third-party integrations
We need strong experience in complex marketplace/web applications, database architecture, authentication/permissions, Row Level Security, state-driven workflows, matching/inventory systems, asynchronous processes/webhooks, APIs, concurrency/data integrity, admin tooling, security, performance and maintainable architecture.
Commercial Launch — Later Stage
The complete transactional platform is not part of the immediate MVP build.
Live payments/payouts, full transaction execution, independent authentication, high-value logistics, shipment insurance, refunds/disputes and related provider integrations belong to a later Commercial Launch development stage.
However, the MVP must be designed modularly so these capabilities can later be added without rebuilding the core marketplace.
Premium UI
A professional Brand Identity and Design System will be created separately by a specialist designer.
The developer is not responsible for creating the Brand Identity, but must implement the supplied Design System across the MVP to a premium production standard, including responsive desktop/tablet/mobile UI, reusable components, polished interactions and performance-conscious front-end development.
Please provide examples of premium interfaces you personally implemented.
First Step — Technical Review / Gap Analysis
Before full MVP development is awarded, the shortlisted developer will review our detailed documentation and:
• assess the architecture and requirements;
• identify technical gaps, risks and dependencies;
• recommend the implementation approach;
• distinguish what must be built now from what only needs architectural preparation for later;
• propose milestones and timeline;
• provide a fixed-price quotation for the Pre-Launch MVP.
We are not requesting a quotation for the complete future platform at this stage.
We prefer an individual senior developer / hands-on technical lead, not someone providing only high-level advice.
Please include:
Relevant marketplace/workflow-heavy applications you personally built.
Next.js/React/TypeScript experience.
Supabase/PostgreSQL experience.
Relevant matching, inventory, permissions or API experience.
Premium UI examples.
Whether you personally develop the project or work through a team/agency.
Your approach to the initial technical review.
Current availability.
Confirmation that initial assessment and communication can be handled in writing through the platform.
Detailed documentation will be provided only to shortlisted candidates.
This is not a standard e-commerce website or simple listings marketplace. The product includes custom buyer/seller workflows, structured buyer demand, seller inventory and supply connectivity, matching, private inventory, progressive item readiness, communications, notifications and administration.
The scope is the Pre-Launch MVP — NOT the complete future Commercial Launch platform.
The MVP will operate with real users, buyer demand, sellers and real supply to validate the marketplace before commercial transactions are activated.
Pre-Launch MVP
The MVP will include:
• Buyer and seller onboarding
• Structured and persistent buyer search/demand workflows
• Seller inventory and supply connectivity
• Manual and bulk inventory ingestion
• Private/hidden inventory
• Configurable, category-specific item information
• Progressive item-data completion
• Demand-to-supply matching
• Seller activation/confirmation when relevant demand exists
• Buyer-visible relevant opportunities
• Item condition information, photos/evidence
• Communications and meaningful notifications
• Buyer/seller account areas
• Admin and operational controls
Detailed workflows and business rules are already documented and will be shared with shortlisted candidates.
Technical Direction
Preferred stack:
Next.js / React / TypeScript
Supabase / PostgreSQL
API-based third-party integrations
We need strong experience in complex marketplace/web applications, database architecture, authentication/permissions, Row Level Security, state-driven workflows, matching/inventory systems, asynchronous processes/webhooks, APIs, concurrency/data integrity, admin tooling, security, performance and maintainable architecture.
Commercial Launch — Later Stage
The complete transactional platform is not part of the immediate MVP build.
Live payments/payouts, full transaction execution, independent authentication, high-value logistics, shipment insurance, refunds/disputes and related provider integrations belong to a later Commercial Launch development stage.
However, the MVP must be designed modularly so these capabilities can later be added without rebuilding the core marketplace.
Premium UI
A professional Brand Identity and Design System will be created separately by a specialist designer.
The developer is not responsible for creating the Brand Identity, but must implement the supplied Design System across the MVP to a premium production standard, including responsive desktop/tablet/mobile UI, reusable components, polished interactions and performance-conscious front-end development.
Please provide examples of premium interfaces you personally implemented.
First Step — Technical Review / Gap Analysis
Before full MVP development is awarded, the shortlisted developer will review our detailed documentation and:
• assess the architecture and requirements;
• identify technical gaps, risks and dependencies;
• recommend the implementation approach;
• distinguish what must be built now from what only needs architectural preparation for later;
• propose milestones and timeline;
• provide a fixed-price quotation for the Pre-Launch MVP.
We are not requesting a quotation for the complete future platform at this stage.
We prefer an individual senior developer / hands-on technical lead, not someone providing only high-level advice.
Please include:
Relevant marketplace/workflow-heavy applications you personally built.
Next.js/React/TypeScript experience.
Supabase/PostgreSQL experience.
Relevant matching, inventory, permissions or API experience.
Premium UI examples.
Whether you personally develop the project or work through a team/agency.
Your approach to the initial technical review.
Current availability.
Confirmation that initial assessment and communication can be handled in writing through the platform.
Detailed documentation will be provided only to shortlisted candidates.
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Log inClarification Board Ask a Question
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- How should the seller inventory workflow operate from initial ingestion through to a buyer-ready item? For example, can sellers initially provide incomplete inventory and progressively add pricing, condition, photos, specifications, and supporting evidence as information becomes available?
- Could you clarify how buyer demand should be matched against seller inventory? Which attributes should influence matching, for example category, item type, specifications, condition, price range, location, or other requirements and are some criteria mandatory while others are preferences?
- What are the exact visibility rules for private inventory? Should sellers be able to keep individual items completely hidden until a qualifying buyer demand exists, and should administrators have visibility into all inventory regardless of its state?