WattTime
WattTime is a nonprofit organization that provides real-time, forecast, and historical data for electric grids around the world, enabling carbon-aware computing and clean energy procurement decisions. The WattTime API delivers marginal emissions data (CO2 MOER), health damage signals, average emissions rates, and renewable energy forecasts for 342 grid regions across 210 countries and territories. Developers and organizations use the API to schedule workloads during low-carbon windows, measure actual emissions reductions from clean energy procurement, and meet sustainability reporting requirements.
Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.
API Evangelist profiles WattTime the way a machine reads it — 81 machine-readable artifacts across 6 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — WattTime scores 35.7/100 (thin), with a separate agent-readiness read of 31/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-08 · rubric v0.20.0
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How we profile WattTime
Each block below is one kind of artifact we hold for WattTime. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 6
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
WattTime Python Client
Official Python SDK for the WattTime API providing simplified access to real-time, forecast, and historical emissions data.
WattTime Account API
Account information and access management.
WattTime Authentication API
Register for an account and obtain access tokens.
WattTime Emissions Data API
Access real-time, historical, and forecast marginal emissions signals for electric grids.
WattTime Forecasts API
Retrieve emissions forecasts and historical forecast data.
WattTime Grid Regions API
Discover and query grid balancing authorities and regions.
Postman Collections 5
A runnable collection turns the contract into something a developer can execute in seconds. We profile them because the fastest way to trust an API is to make a real call against it.
Ready-to-run Postman collections for exercising this provider's APIs.
WattTime Account API
POSTMANOpen Collections 7
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
API Collection
OPEN COLLECTIONWattTime Account API
OPEN COLLECTIONWattTime Account Authentication API
OPEN COLLECTIONWattTime Account Emissions Data API
OPEN COLLECTIONWattTime Account Forecasts API
OPEN COLLECTIONWattTime Account Grid Regions API
OPEN COLLECTIONWattTime API
OPEN COLLECTIONScroll within the panel for all 7 ·
Pricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the things the Kin Score reads for access clarity — renamed from commercial clarity in rubric 0.12, because a free statutory interface has access terms and no commercial ones.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Watttime Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Watttime Finops
FINOPSFeatures 7
The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.
Notable capabilities this provider offers.
Real-Time Marginal Emissions
CO2 MOER signal providing real-time marginal carbon intensity for local grid regions, updated every 5 minutes via the forecast endpoint.
Emissions Forecasting
24-72 hour ahead emissions forecasts enabling applications to schedule energy-intensive workloads during low-carbon grid windows.
Historical Data Access
Historical MOER data available for up to 32 days via the data endpoint, and multi-year historical datasets downloadable as CSV files.
Health Damage Signal
Estimates the damage to human life and health caused by emissions from electricity generation based on time and location of consumption.
Global Grid Coverage
Coverage across 342 grid regions in 210 countries and territories, including North America, Europe, and global expansion with synthetic demand proxy models.
Grid Region Discovery
Identify the relevant balancing authority for any geographic coordinates and retrieve the list of accessible grid regions.
Model Versioning
Date-based model versioning (e.g., 2026-03-01) allowing unique versions per region and signal for reproducibility and comparison.
Scroll within the panel for all 7 ·
Semantic Vocabularies 1
JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.
JSON-LD contexts and semantic vocabularies used across these APIs.
Watttime Context
JSON-LDSpectral Rules 2
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
WattTime API Rules
SPECTRALWattTime API Rules
SPECTRALJSON Schema 13
Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.
Standalone JSON Schema definitions for this provider's data models.
DataMeta
JSON SCHEMADataPoint
JSON SCHEMADataResponse
JSON SCHEMAForecastMeta
JSON SCHEMAForecastResponse
JSON SCHEMAGridMapsResponse
JSON SCHEMAHistoricalDownloadResponse
JSON SCHEMALoginResponse
JSON SCHEMAMyAccessResponse
JSON SCHEMARegionAccess
JSON SCHEMARegionResponse
JSON SCHEMARegisterRequest
JSON SCHEMARegisterResponse
JSON SCHEMAScroll within the panel for all 13 ·
JSON Structure 13
JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.
JSON Structure definitions describing this provider's data shapes.
Watttime Data Meta Structure
JSON STRUCTUREWatttime Data Point Structure
JSON STRUCTUREWatttime Data Response Structure
JSON STRUCTUREWatttime Forecast Meta Structure
JSON STRUCTUREWatttime Forecast Response Structure
JSON STRUCTUREWatttime Grid Maps Response Structure
JSON STRUCTUREWatttime Historical Download Response Structure
JSON STRUCTUREWatttime Login Response Structure
JSON STRUCTUREWatttime My Access Response Structure
JSON STRUCTUREWatttime Region Access Structure
JSON STRUCTUREWatttime Region Response Structure
JSON STRUCTUREWatttime Register Request Structure
JSON STRUCTUREWatttime Register Response Structure
JSON STRUCTUREScroll within the panel for all 13 ·
Examples 13
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Watttime Data Meta Example
EXAMPLEWatttime Data Point Example
EXAMPLEScroll within the panel for all 13 ·
Security Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Use Cases 5
What developers actually build with this provider — captured so the catalogue answers 'what is this for', not just 'what does this expose'.
What developers build with this provider.
Carbon-Aware Computing
Technology companies and cloud providers schedule compute workloads, data transfers, and batch jobs to run during periods of low marginal carbon intensity.
Clean Energy Procurement
Organizations measure the actual emissions reductions from renewable energy procurement and power purchase agreements using marginal emissions data.
Sustainability Reporting
Enterprises report Scope 2 emissions more accurately using marginal emissions rates rather than average grid emission factors.
Smart Building Optimization
Building energy management systems shift heating, cooling, and EV charging to low-emission grid windows to reduce carbon footprint.
Grid Research and Analysis
Researchers, utilities, and policy makers analyze historical and forecast emissions data to study grid decarbonization trends.
Integrations 3
Pre-built integrations with other platforms tell you where this provider already fits in a stack.
Pre-built integrations with other platforms and tools.
Green Software Foundation
WattTime provides the carbon intensity data underlying the Green Software Foundation's Software Carbon Intensity (SCI) specification.
Climate TRACE
WattTime contributes emissions data and modeling to the Climate TRACE global emissions inventory.
Impact Framework
Official Green Software Foundation Impact Framework plugin available for integrating WattTime data into software sustainability measurements.
Resources
Every other property we hold for WattTime — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 1
Portal, sign-up, and the first successful call
Documentation 1
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 3
Pagination, idempotency, versioning, errors, and events
Build 2
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Operate 3
Status, limits, changes, and where to get help
Company 3
The organization behind the API
← All providers · Data indexed from github.com/api-evangelist/watttime · machine-readable index on apis.io
This is an independent, third-party profile of WattTime, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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