Methodology Execution

Overview

Methodologies define the scientific basis for environmental credit generation. Each methodology is translated into a methodology framework (MvF) — the specification of rules, triggers, and verification criteria — and implemented as a Methodology Verification Application (MvA) that executes those rules on the platform under that framework. The platform receives structured data from Network Integrators, processes it through the MvA against the methodology framework's rules, and produces verified outcomes — MassIDs and certificates that become the foundation for credits issued on the public registry.

This page explains the end-to-end execution pipeline: how data enters the platform, how it is processed, and how verified outcomes are produced. Rule execution and results are persisted after each rule and reported in real time in the Carrot Registry (registry.carrot.eco).

How data enters the platform

Network Integrators submit supply chain data via the Carrot API. This data describes the physical events occurring across the recycling supply chain:

Facility accreditation is not part of what integrators submit. Accreditation records — and the third-party on-site facility verification behind them — are maintained by Carrot in the accreditation layer, and the verification pipeline reads them when it evaluates a MassID. Integrator submissions cover waste movements and environmental outcomes.

Each submission is stored as a versioned record that captures the state of the data at a specific point in time. Recorded data is append-only — through the API it cannot be edited or deleted, only extended with new events or versions. Every change to supply chain data is traceable, creating a complete audit trail from initial submission through final verification.

Processing and verification

When new data arrives, the platform processes it through a structured pipeline:

1. Document recognition — The platform identifies the type of incoming data (waste movement, audit report, issuance event) and routes it for appropriate processing.

2. Entity synchronization — Relevant entities — MassIDs, certificates, and participant records — are updated to reflect what happened in the physical world. For example, a drop-off event updates the MassID's chain of custody to include the receiving facility.

3. Trigger evaluation — The platform checks whether any methodology triggers apply to the incoming data. If a trigger condition is met, the corresponding methodology framework rules are queued for execution by the MvA.

Methodology triggers

Each methodology framework (MvF) defines triggers — conditions on incoming data that, when matched, cause rules to execute. Triggers connect real-world events to the verification logic that produces environmental outcomes. The exact trigger conditions are defined per framework; see the methodology catalog for each framework's behavior.

Rule execution

When a trigger fires, the platform executes the methodology framework's rules via the MvA in a defined sequence. After each rule runs, its result is persisted and made available in real time in the Carrot Registry.

1. Prepare

The platform determines which rules apply to the triggered scope and establishes the execution order. Each methodology framework defines its rules as an ordered sequence, ensuring consistent evaluation regardless of when the trigger fires.

2. Evaluate

Each rule in the sequence is executed. A rule evaluates conditions against the current data, performs calculations where required, and produces outputs. Rules can validate material types, check chain-of-custody completeness, calculate weights, or evaluate compliance against methodology-specific criteria. Each rule's result is persisted immediately and visible in the Carrot Registry, so execution progress and outcomes are available in real time.

3. Review when needed

Rules the code cannot settle on their own return a review-required verdict. The run then pauses for a recorded human decision: a reviewer approves or rejects each flagged rule with a mandatory written justification, and the decision is stored with the run alongside the reviewer's identity and the time it was made. If the review window closes with flagged rules still undecided, those rules are rejected automatically and the verification fails.

4. Finalize

After all rules complete — and after any required review is resolved — the platform finalizes the outputs: certificates are issued from the verified MassIDs and published in the Carrot Registry with the amount of credit each corresponds to, and state is updated across all affected entities. Recording on the public ledger is a separate step: Carrot records certificates there as inventory is needed, not all at once, with each certificate's MassID recorded first and its credits issued in the same transaction. The rule results and review decisions are shown in the Carrot Registry, and a recorded certificate's metadata links to a public audit report on IPFS that lists each rule executed and its result.

Outcomes

Methodology execution produces two primary outcomes:

• Verified MassIDs — MassIDs that have passed all methodology checks. Their chain of custody is complete, material type and weight are validated, and all compliance conditions are satisfied. A verified MassID is recorded on the public ledger before any certificate from it can be.

• Certificates — When a MassID passes all methodology verification rules at an accredited facility, certificates (RecycledID or GasID) are issued and published in the Carrot Registry. Certificates link the verified environmental outcome to the underlying MassID; when a certificate is recorded on the public ledger, its fungible credit tokens are minted in the same transaction.

To generate a certificate or credit, the tracked mass must satisfy every applicable framework criterion. Most criteria are settled by code-based validation, and a criterion the code decides against blocks certificate issuance and credit generation until the issue is corrected under the applicable framework. Criteria the code cannot settle on its own are resolved through the recorded human review described above — an approved review resolves the criterion without code deciding it, and a rejected one fails the verification.

Only data that is intended to be public is registered on the public blockchain — for example, minted MassIDs, Certificates, credit tokens, and retirement receipts. That on-chain data is publicly accessible: viewable through any blockchain block explorer (e.g. PolygonScan) or the Carrot Registry, which provides a user-friendly, domain-focused view of rule execution and outcomes for auditors, regulators, and credit buyers.

Related pages

• dMRV — The execution and evidence process for approved methodology framework criteria
• MvF and MvA — How methodology frameworks and their implementations define and execute rules
• Registry Record Creation — How verified MassIDs become public registry records
• Methodologies — The validated scientific bases and their frameworks that define verification rules