Overview

When building map-based real estate applications with Repliers API data, you may encounter a common challenge: multiple listings sharing the exact same coordinates. This is especially prevalent in condo buildings where dozens of units might be at the same latitude and longitude.

The Problem

In dense urban markets—particularly condominiums—many units share identical coordinates. Regardless of the level of zoom these units will be positioned at precisely the same point.

This may lead to a few challenges:

• Discoverability – The map shows one pin when there are actually many listings
• Clickability – Only the topmost marker is interactive
• User confusion – Does the pin represent a building, a unit, or something else?

Any solution needs to answer:

• How do we signal that multiple listings exist at this location?
• How does the user select a specific unit?
• How do we maintain geographic accuracy without overcomplicating the UI?

Pattern 1: Building-Level Marker with Multi-Listing Popup Panel

Display one marker per building/location with multiple units. When users click:

• Open a popup panel showing all units at that building
• Display each unit as a card with key details (price, beds, baths, photos)
• Allow users to click through to individual listing details

Pattern 2: Spiderfy/Exploding Markers

Keep one pin at the building location. On click or hover:

• "Explode" overlapping markers outward in a circle or spiral
• Each unit gets its own clickable marker
• Optional connecting lines show relationship to the true location
• Clicking an expanded marker opens that listing

Popular mapping libraries offer spiderfy plugins:

• Leaflet: Leaflet.markercluster with spiderfy options
• Mapbox GL JS: Custom implementation or community plugins
• Google Maps: OverlappingMarkerSpiderfier library

Pattern 3: Count Badge + List Panel

• Display markers with count badges (e.g., "5" for 5 listings)
• Clicking the marker scrolls/focuses on an adjacent list panel
• All selection happens in the list, not on the map
• Map acts as a locator rather than the primary interaction surface

Conclusion

There's no single "correct" solution—each approach involves trade-offs between visual clarity, interaction complexity, geographic accuracy, and implementation effort.

The best pattern for your application depends on factors like your primary user interface (map vs. list), market density, data model structure, and user expectations.

Consider your specific use case: a consumer-facing search portal may prioritize visual discovery through spiderfy animations, while a professional agent tool might benefit from a clean count-badge approach with robust list panels.

Limitations on this topic

Repliers is a real estate technology company specializing in headless MLS related solutions. We provide a robust API infrastructure that delivers data and functionality to power real estate applications—but we don't offer GUI, UX design, or front-end direct assistance and implementation as part of our subscription plans.

This article is provided as courtesy guidance to help developers understand common patterns and considerations when building map-based interfaces with MLS data. The design decisions, user experience choices, and technical implementation remain entirely within the customer’s control and should be tailored to one’s specific application requirements and user needs.

Updated on: 06/01/2026