MassIDs

What is a MassID?

A MassID represents a verified batch of environmental materials in the Carrot Network — the foundational registry record for the digital MRV (dMRV) process. On the network's public registry, each MassID is a permanent, non-transferable record held by the Vault.

When any amount of post-consumer or post-industrial waste is identified, measured, and custody is established between two parties, a MassID is created on the Registry's immutable ledger. It records three core properties:

• Material type — What the waste is (e.g., clear glass, organic food waste, mixed plastics)
• Weight — How much there is (in kilograms)
• Chain of custody — Every participant who has handled the material, from source to recycling

MassID metadata is stored on IPFS — the InterPlanetary File System — where content addressing makes it tamper-evident and publicly verifiable; continued availability depends on active pinning. The immutable registry reference links that metadata to each waste batch and its journey through the recycling supply chain.

Chain of custody

The chain of custody recorded in each MassID tracks every participant who handles the material. Participants fall into six role categories:

Each role category can include multiple participants. For example, a glass recycling chain might involve two haulers (local collection and long-distance transport) and two processors (local accumulation center and the glass bottling plant).

Every participant in the chain of custody is identified by their account address and is eligible for a share of the rewards when credits are issued from the MassID.

How MassIDs are created

MassIDs are generated in three main scenarios:

1. Bin drop-off

When a user drops waste at a collection point. If the product can be uniquely identified (via QR code, barcode, or AI recognition), MassIDs are created matching the waste composition of that product.

2. Waste pick-up

When a hauler collects waste from a generator. The graduated precision model incentivizes weighing at source: generators who weigh at pick-up receive more accurate credit attribution and, in Pay-As-You-Throw programs, lower bills.

3. Drop-off at processors and recyclers

When waste arrives at a facility, the validator confirms the material content (type and weight). MassIDs in the facility's inventory are managed on a First-In-First-Out (FIFO) basis — the earliest MassIDs are processed and credited first.

Proof of Physical Work and Provenance

MassIDs provide two forms of verifiable proof:

• Proof-of-Provenance — The chain of custody establishes where the waste came from and who handled it at every stage, creating a traceable path from source to recycling.

• Proof-of-Physical-Work — Each supply chain event recorded in the MassID (pick-up, drop-off, shipment, sorting, recycling confirmation) constitutes evidence that real physical work was performed — waste was collected, transported, sorted, and recycled.

Together, these proofs form the basis for the dMRV process that leads to credit generation. Only MassIDs that reach a certified recycling or biological treatment facility, with validated chain of custody at each point, become eligible for generating credits.

This permanent registry record is the foundational technology enabling the Recycle-to-Earn model — where every verified participant in the recycling supply chain receives rewards proportional to their contribution.

After a MassID passes all verification checks and is eligible for generating a Certificate, it is permanently recorded on the registry — its content-addressed metadata is stored on IPFS, with availability dependent on continued pinning, and the MassID reference is written to the registry.

Learn about dMRV verification · Explore the credit lifecycle