Waste Classification
Waste classification system — Category, Type, and Subtype hierarchy used in document payloads.
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Every document submitted to the Carrot API is classified using a three-level hierarchy: Category, Type, and Subtype. The first two levels are required; the third is optional in the API, though a methodology may require it. This structure organizes documents for grouping, traceability, and methodology validation.
Classification hierarchy
A subtype always belongs to a type, and a type always belongs to a category. This ensures that each document is positioned correctly within the platform's classification context.
Category
The broadest classification level. It indicates the general context of the document. For supply
chain integrations, the category is typically MassID, which refers to documents tracking the
history of a waste mass.
Other categories (such as Methodology) exist for internal platform flows and are not used in
standard integrations.
Type
The type identifies the primary material or process class within a category. Under the MassID
category, the type is one of:
GlassMetalOrganicPaperPlastic
This is the vocabulary the platform recognizes downstream — certificate issuance and the public
MassID API both parse type against exactly these five values and drop records outside them.
POST /documents itself accepts type as a free string, so a value outside this list is accepted at
submission and dropped later.
Subtype
The subtype provides the most specific classification, refining the type with detailed information about the material. For example:
- For type
Plastic:PET— the only accepted plastic subtype - For type
Organic:Domestic Sludge,EFB similar to Garden, Yard and Park Waste,Food, Food Waste and Beverages,Garden, Yard and Park Waste,Industrial Sludge,Others (if organic),Tobacco,Wood and Wood Products
Subtypes must be sent in English. The accepted subtypes depend on the methodology under which the mass will be audited — consult the methodology-specific integration guide for the full list.
Methodology-specific subtypes
Each methodology defines the accepted subtypes for validation. A mass submitted for a methodology must use one of its accepted subtypes to pass validation rules.
Validation expectations
categoryandtypeare required on every document.subtypeis optional in the API, but a methodology may require it — a MassID without a subtype cannot pass methodology verification under a methodology that defines accepted subtypes, so no certificate is issued from it.- Category/type combinations should follow your approved business taxonomy.
- Keep mappings deterministic across environments (test and production).
- Validate unsupported combinations before API submission to avoid rejection.
External code systems
Some methodologies require external waste classification codes alongside the Carrot subtype. These codes connect the Carrot classification to national or international standards.
Ibama codes (Brazil)
Ibama (Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais
Renováveis) publishes the
Brazilian List of Solid Waste
(Lista Brasileira de Resíduos Sólidos, per IN nº 13/2012). Each waste material is assigned a 6-digit
code (for example, 02 01 01). Include the Ibama code and description in the
Local Waste Classification ID and Local Waste Classification Description metadata attributes.
CDM waste categories
The CDM (Clean Development Mechanism) Tool 04 v08.1 defines waste
categories used for emission factor assignment. Each Ibama code maps to a CDM category (for example,
8.3 for food waste). The methodology uses this mapping to select the correct emission factors.
Methodology-specific code lists
BOLD Carbon requires both Ibama and CDM codes, validated by the regional-waste-classification rule.
See the
BOLD Carbon Framework — Supported waste codes
for the complete list of accepted Ibama codes and their CDM mappings.
Related references: