NFT Marketplace.
An API-first backend for digital assets built to be reused across front ends
A Web3 venture building a marketplace brand with several planned front ends and partner integrations.
Web3 / digital assets
2024
The challenge.
The marketplace logic — collections, listings, offers, royalties, activity feeds — had to be exposed as a stable API that web, mobile and partner integrations could all consume, while staying consistent with on-chain state and surviving blockchain reorganisations and RPC failures.
What we built.
We implemented a Python backend with FastAPI and SQLAlchemy on PostgreSQL, structured around clear domain services and an event indexer that reconciles on-chain events with the database. Idempotent processing and reorg handling keep listings accurate; OpenAPI documentation makes partner integration straightforward.
- Domain services for collections, items, listings, offers and activity
- On-chain event indexer with retries, idempotency and reorg handling
- Search and filtering with pagination designed for large collections
- Metadata and media pipeline with IPFS and caching
- OpenAPI-documented endpoints and auth for partner integrations
Outcome.
- 01
One backend serving multiple front ends and partner integrations
- 02
Consistent marketplace state even under RPC failures and chain reorgs
- 03
Documented API that shortened partner onboarding
Technology stack.
Python, FastAPI, SQLAlchemy and PostgreSQL with an EVM event indexer.
- Python
- FastAPI
- PostgreSQL
- SQLAlchemy
Building something similar?
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