find_apisBrowse and filter every API in the catalog.
get_api_artifactsOne API's artifacts, grouped by type.
get_openapiThe primary OpenAPI for this API.
find_similar_apisAPIs that look like this one.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This API

curl "https://apis.io/api/v1/apis/emission-factors-com:emission-factors-com-compare-api"

All apis

curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

openapi: 3.2.0
info:
  title: emission-factors.com Compare API
  version: 2.1.0
  description: 'US electricity and fuel emission data by ZIP code: EPA eGRID Scope 2 factors (location-based) with the Green-e residual mix (market-based), Scope 1 fuel factors, EIA retail rates and hourly grid intensity, EPA CAMD plant emissions and OpenEI utility tariffs. Free, no key. Query parameters and JSON body fields not listed here are rejected with 400.'
  contact:
    url: https://emission-factors.com
  license:
    name: 'Data licenses vary by source: US government works (public domain); eGRID2024, GHG Hub 2026, OpenEI URDB and ZIP-to-utility data, and GeoNames are CC-BY-4.0; the Green-e residual mix is published by the Center for Resource Solutions. See /methodology.'
    url: https://emission-factors.com/methodology
servers:
- url: https://emission-factors.com
  description: Production
tags:
- name: Compare
paths:
  /api/compare:
    post:
      summary: Rank 2-25 candidate sites on grid carbon, retail $/kWh and cleanest daily window
      operationId: compareSites
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - zips
              properties:
                zips:
                  type: array
                  items:
                    type: string
                  minItems: 2
                  maxItems: 25
                  example:
                  - '20147'
                  - '79601'
                  - '97058'
                annual_kwh:
                  type: number
                  example: 87600000
                  description: Optional; adds annual tCO2e and cost per site
                sector:
                  type: string
                  enum:
                  - COM
                  - IND
                  - RES
                  - ALL
                  - Commercial
                  - Industrial
                  - Residential
                  default: COM
                duration:
                  type: integer
                  minimum: 1
                  maximum: 12
                  default: 4
                  description: Cleanest-window length in hours
      responses:
        '200':
          description: Sites with factors, rates, cleanest window and rank_carbon / rank_cost / rank_combined
        '400':
          description: Fewer than 2 or more than 25 ZIPs, or invalid input
        '429':
          description: Rate limit reached while fetching per-site data (compare costs about 1 + sites + states + BAs requests)
      tags:
      - Compare