A federated, Digital Product Passport (DPP)-compatible protocol enabling cities to track, exchange, and settle material and product flows while maintaining local sovereignty.
Definitions follow the LOOP Specification (§2 and §2.1).
Local Optimization with Overflow Protocol — An open, federated standard for tracking material and product flows between cities. LOOP enables municipalities to share surplus resources, coordinate circular economy initiatives, and maintain sovereignty over local data while participating in regional exchanges — built around MaterialDNA, ProductDNA, LoopCoin, and LoopSignal.
A unique digital identity for physical materials. MaterialDNA captures a material's composition, origin, quality metrics, and chain of custody — enabling trusted exchanges and full lifecycle tracking from source to reuse. Think of it as a passport for materials in the circular economy.
A DPP-aligned identity for finished products. ProductDNA captures product category, condition, manufacturer, lifecycle stage, and references to constituent MaterialDNA entries — enabling product-level reuse, trading, and EU Digital Product Passport compliance (ESPR Art. 9-10).
A node-issued local currency used to settle material and product transfers between federation peers. LoopCoin carries expiry and decay rules defined by each node, keeping value circulating locally while enabling inter-node clearing.
A community preference signal that expresses demand or surplus intent for specific material categories. LoopSignals inform routing and matching across the federation, helping nodes prioritise the right resources for the right places.
The total routing cost for any material or product transfer: base price plus export and import penalties (derived from LoopSignals) plus distance cost. LoopCost ensures local exchanges are always cheaper than cross-boundary ones, keeping circular value circulating close to its source.
Full specification, schemas, and security requirements.
Learn moreJSON-LD contexts, JSON Schemas, and example payloads.
Learn moreSee LOOP in action with city-specific implementations.
Learn moreRFC process, decision-making, and community proposals.
Learn moreWhether you're a city, operator, or developer, there's a place for you in the LOOP ecosystem.
