# MyCO2 Suite — Spend-Based Carbon API (Transactions)

> The MyCO2 spend-based endpoint converts a financial transaction into verified CO₂e. Send a spend amount, currency, country and an industry code (MCC, NAICS, BEA, ISIC, SIC or NACE); it returns Scope 3 emissions in grams, kilograms and tonnes, with the exact emission factor, methodology, source and licence used.

Endpoint: POST https://api.myco2suite.io/v1/transaction
Price: $0.003 / call (from the first call). Pay with an API key (x-api-key) or, with no signup, via x402 pay-per-call in USDC on Base — a keyless request returns HTTP 402 with machine-readable payment requirements.
Free tier: 1,000 calls/month with a key (get one at https://myco2suite.io).

## Inputs
- spend_amount (required): Amount spent (> 0)
- currency (required): ISO 4217 currency, e.g. USD
- country (required): ISO 3166-1 alpha-2, e.g. US
- mcc (optional): Merchant Category Code (or bea_code / naics / isic / sic / nace — one required)
- year (optional): Reporting year

## Example request
POST https://api.myco2suite.io/v1/transaction
Header: content-type: application/json
Header: x-api-key: <your key>   # or pay per call via x402 (no key)
Body: {"mcc":"5411","spend_amount":100,"currency":"USD","country":"US"}

## Example response (JSON)
{
  "co2e_kg": 28.45,
  "co2e_tonnes": 0.02845,
  "factor": {
    "value": 0.2845,
    "unit": "kg_co2e_per_usd",
    "source": "US EPA USEEIO v2.1",
    "licence": "Public Domain",
    "scope": "scope_3"
  }
}

Every response is methodology-stamped: it includes the exact factor value, unit, source, licence, data year, gas basis (CO2 vs CO2e) and GWP version used.

## Common use cases
- Estimate the carbon footprint of card, bank or expense-line transactions
- Add Scope 3.1 purchased-goods estimates to fintech and accounting apps
- Give an AI agent a tool to footprint any purchase on demand

## Related capabilities
- https://myco2suite.io/carbon/activity (activity)
- https://myco2suite.io/carbon/factor (factor)
- https://myco2suite.io/carbon/cbam (cbam)

## Links
- Human page: https://myco2suite.io/carbon/transaction
- Full API docs: https://myco2suite.io/docs
- Full agent/LLM docs: https://api.myco2suite.io/llms.txt
- Code examples: https://github.com/Jaws22/myco2-examples
- MCP server: https://api.myco2suite.io/v1/mcp (registry: io.myco2suite/carbon-intelligence)
- Contact: admin@myco2suite.io