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. Once issued to the network's public registry, each MassID is a non-transferable, tamper-evident record held by the Vault. A network operator can revoke a MassID when its underlying data is later invalidated; revocation is blocked once credits from its certificates have been sold, and the linked certificates have to be revoked first.

When any amount of post-consumer or post-industrial waste is identified, measured, and custody is established between two parties, a MassID is recorded on the Carrot platform. It is tokenized on the public registry only after it passes dMRV verification (see below). 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 or directed where it went, 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 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, directs where it goes, or submits its data. Participants fall into the following 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).

The public record proves the chain without exposing the people in it. Every participant in the chain of custody is recorded under a stable participant identifier, and the MassID record carries only that identifier — as a non-reversible hash — alongside the participant's role, never a name or a blockchain address. Locations are published at city level, with coordinates rounded to roughly 0.1 degrees. Elsewhere on the network, such as reward tables and participant profiles, Processors, Recyclers and Network Integrators may be named when the organization has a public profile; the other chain-of-custody roles are withheld by default and are not named there.

Rewards are linked to participants through that same identifier. Each participant is eligible for a share of the proceeds when credits generated from that MassID are sold.

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.

Submission window

Data can — and should — reach the network as the operation happens: a batch recycled today can be submitted today. What follows is a deadline, not the opening of a window.

The methodology framework sets the outer limit

Both methodology frameworks accept a batch only when its Recycled event occurred on or after 1 January of the previous calendar year, in UTC — the allowable project period, published as Project period under BOLD Recycling key parameters and BOLD Carbon (CH₄) key parameters. A MassID outside that period fails methodology verification and generates no credit, whenever it was sent.

So the year the material was recycled is what decides which cycle is its last. The boundary is evaluated on the event's UTC timestamp, so a Recycled event registered on 31 December at or after 21:00 Brasilia time already counts as the following year:

How each cycle closes

• Until 30 November, 23:59 (UTC-3, Brasilia time) — mass data and the required supporting documentation must reach the network to be analyzed in that year's cycle.
• From 1 to 15 December — the period reserved for methodology verification, the third-party assurance work around it, and the resulting adjustments, followed by the issuance of the approved cases. Corrections requested for submissions received within the deadline are still accepted during this period.

The window exists because verification, the assurance work that supports it, and any adjustments they require need time between the data cut-off and the close of the cycle.

15 December is the target closing date for the cycle, not a guarantee of issuance: a MassID only generates a credit when its documentation is complete and it passes methodology verification.

Submissions received after 30 November — and cases still pending when the cycle closes — are assessed in the following cycle whenever the allowable project period still covers them. A batch already in its last eligible year has no following cycle: once the year turns, its Recycled event falls outside that period.

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, 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 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.

A MassID that passes all verification checks is eligible for generating a Certificate. Before any certificate from it can be recorded on the public registry, the MassID itself is recorded there — 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