Developing an NFT Collection Browser for Mobile Apps
The difference between this task and displaying collections in a wallet is fundamental: here the user browses other people's collections, explores the marketplace, filters by attributes and price. This is closer to e-commerce with a cryptocurrency twist—an endless feed of thousands of tokens, complex filters, and up-to-date prices. Our team has over 5 years of experience in mobile NFT development, completed 20+ projects with integration of OpenSea API and Reservoir API. We guarantee fast loading and smooth UX even with 10,000+ tokens.
How to Choose an API for an NFT Collection Browser?
The primary data source is OpenSea API v2. It's the richest source: collections, tokens, floor price, trade volumes, events (listings, sales). For public browsing without authentication—GET /api/v2/collection/{slug}/nfts with pagination by next cursor. Limit: 4 req/s on free plan.
Reservoir API aggregates data from OpenSea, Blur, LooksRare, X2Y2. For apps with trading features it's preferable: a single endpoint for floor price and best offer regardless of the marketplace.
Alchemy NFT API—getNFTsForCollection returns all tokens of a collection with metadata; getFloorPrice gives floor by marketplace.
For Solana collections: Magic Eden API (/collections/{symbol}/listings) or Tensor API.
| API | Data | Limits | Trading Features |
|---|---|---|---|
| OpenSea v2 | Tokens, collections, prices, events | 4 req/s (free) | Yes (listings, sales) |
| Reservoir | Aggregated from multiple exchanges | 2 req/s (free) | Yes (best offer, floors) |
| Alchemy | Tokens, metadata, floor | Depends on plan | Limited |
Reservoir returns a unified best offer 2–3 times faster compared to polling OpenSea and Blur separately. This saves 100–200 ms per token card load and reduces API request costs.
How to Implement Infinite Scroll and Pagination?
Collections like Bored Ape Yacht Club have 10,000 tokens. Loading everything at once is impossible. OpenSea returns cursor-based pagination (next in the response body). We implement via Paging 3 (Android) or a custom PaginatedViewModel on iOS with AsyncSequence.
On Flutter: infinite_scroll_pagination package. Load the next page when 80% of the list is reached, not at the very end—otherwise the user sees an empty space.
Caching scheme
Cache the first page in Room/CoreData—upon next open the screen appears instantly, updates happen in the background (stale-while-revalidate). This gives a feeling of speed 2x faster than without cache, and saves up to 40% of time on reloading.
Filtering and Sorting by Attributes
This is the most nontrivial part. NFT attributes have a dynamic schema: one collection has Background, Fur, Eyes; another has Rarity, Element, Power. The structure is unknown upfront.
Approach: on first load of the collection, request getContractMetadata or /collection/{slug}/attributes—get a list of trait types with values and rarity. Build the filter UI dynamically: ExpandableSection per trait type, Checkbox list for values.
Attribute filtering on the API side: OpenSea accepts trait_type/value as query params. Reservoir uses a JSON body with an array of filters. Local filtering only works if the entire collection is cached—for 10K tokens this is unrealistic.
Sorting: by price (asc/desc), by rarity (needs a rarity score—either compute from attributes or fetch from rarity.tools API). By token number.
Detailed Token Card
Fast loading is critical. Image—immediately in maximum resolution, not after tap. Card structure:
- Media: image, animated GIF, video (AVPlayer / ExoPlayer), 3D (SceneKit / SceneView Flutter)
- Traits as chips with rarity percentage
- Current listing and best offer
- Price history (sparkline graph via Charts framework / MPAndroidChart)
- "Buy" button—if marketplace SDK is integrated
Transition to card—shared element transition: image from grid smoothly enlarges. iOS: UIViewControllerTransitioningDelegate + UIPresentationController. Android: sharedElementEnterTransition with Compose sharedBounds.
What's Included in the Deliverable?
We provide a full package: API integration documentation, commented source code, configured authorization schemes (OAuth/API keys), deployment instructions for App Store and Google Play, and 30-day post-delivery support. We guarantee compliance with App Store Review Guidelines (Sections 4.2, 5.1) and Google Play policies.
Pagination Library Comparison by Platform
| Platform | Library | Features |
|---|---|---|
| Android | Paging 3 | Built-in Room support, RxJava, LiveData, coroutines |
| iOS | PaginatedViewModel (AsyncSequence) | Custom but flexible; easy to customize preloading |
| Flutter | infinite_scroll_pagination | Simple setup, ScrollController support |
The cost of developing an NFT collection browser depends on integration complexity and chosen API. Budget savings are achieved by using ready-made components and caching. Assess your project—contact us for a free requirements analysis. We'll select the optimal solution and suggest timelines. Order a turnkey NFT browser development and get a finished product with marketplace integration in 3–5 days.