Certificates
GasID and RecycledID — methodology-specific credentials that verify environmental outcomes and link MassIDs to credits.
What are certificates?
Certificates are the middle layer of the Carrot Network's token hierarchy — they sit between MassIDs (which track physical waste) and Credits (which are bought and sold on the market). A certificate represents a single MassID that has passed methodology verification, proving a specific quantity of recycling or emissions avoidance. On-chain, each certificate is soulbound (non-transferable) and held by the Vault; when it is minted, a matching amount of fungible credit tokens is created automatically (1 credit = 1 metric ton).
This ensures that every credit in circulation is backed by a verified certificate, which is in turn backed by a verified MassID.
Certificate types
The Carrot Network issues certificate types that are tied to methodologies. Each methodology defines which certificate type it issues and which credit symbol is minted:
| Certificate | Credit generated (example) | Issued by | What it verifies |
|---|---|---|---|
| RecycledID | C-BIOW (TRC) when issued under BOLD Recycling | Recycling methodologies | That a specific quantity of waste material was certified recycled at an accredited facility |
| GasID | C-CARB.CH4 (TCC) when issued under BOLD Carbon (CH₄) | Carbon methodologies | That a specific quantity of greenhouse gas emissions (CO₂e) was avoided through recycling |
Other methodologies may issue different credit symbols for their certificates.
RecycledID
A RecycledID certificate is issued when a MassID of a specific waste type reaches an accredited Recycler, passes dMRV verification, and satisfies all rules defined by an active recycling methodology. The certificate records the weight of certified recycled material and references the underlying MassID that proves provenance. Under the BOLD Recycling methodology, each RecycledID generates a corresponding amount of C-BIOW credit tokens; other recycling methodologies may issue different credit symbols.
GasID
A GasID certificate quantifies the greenhouse gas emissions that were avoided by recycling waste instead of sending it to a landfill or dump. GasIDs are generated directly from MassIDs by a carbon methodology: the avoided emissions are calculated by comparing the recycling scenario against the baseline scenario (what would have happened to the waste without recycling).
The core calculation is: Avoided Emissions = Baseline Emissions − Real Emissions. Under the BOLD Carbon (CH₄) methodology, each GasID generates a corresponding amount of C-CARB.CH4 credit tokens (methane avoidance); other carbon methodologies may issue different credit symbols.
How certificates are created
Verified MassIDs produce certificates, which mint fungible credit tokens deposited in the Vault.
The certificate lifecycle follows a clear sequence:
- MassIDs accumulate — As waste moves through the supply chain, MassIDs are created and validated at each transfer point.
- Methodology verification passes — When MassIDs satisfy all rules defined by a specific methodology — whether a recycling methodology (producing a RecycledID) or a carbon methodology (producing a GasID) — the MassIDs become eligible for certification.
- Certificates are minted — The
InventoryManagersmart contract mints each certificate and links it to its parent MassID via theCertificateRegistry. The platform records the issuance event, syncing the certificate to its backing MassID, credit type, amount, and methodology context. - Credits are generated — At the same time, fungible credit tokens are minted in an amount matching the certificate and deposited into the Vault as available inventory for credit purchases.
Certificate tracking
Each certificate tracks its available balance as credits are purchased and retired:
- Total amount — Set at minting, immutable. The total environmental impact this certificate represents.
- Purchased amount — Incremented when credits backed by this certificate are purchased.
- Retired amount — Incremented when purchased credits are permanently retired.
- Available amount — Total minus purchased. The credits still available for sale.
This tracking ensures that every credit purchase and retirement can be traced back to a specific certificate, and through that certificate to the underlying MassID and physical recycling work.