Kelvin

Kelvin (kelvin°) is a Paris-based startup, founded in 2023 and backed by Seedcamp, building an AI-powered commercial platform for the home energy-renovation industry in France. Its tools help RGE-certified artisans, renovation contractors, general contractors, CEE delegatees and trade platforms find and qualify renovation prospects, generate leads through embeddable address-based simulators, automatically compute energy-efficiency scenarios and government aids (MaPrimeRenov / CEE) with remaining customer cost, and assemble complete financing packages. The AI is trained by thermal engineers and architects and uses open data plus computer vision to assess buildings without a recent DPE. More than 4,000 artisans and sales reps use Kelvin to prospect, prepare appointments and quote work.

Kelvin publishes 4 API contracts indexed on the APIs.io network, including Documents API, Qualification API, Simulateur API, and 1 more. Tagged areas include Company, Energy, Energy Efficiency, Home Renovation, and Construction.

The Kelvin catalog on APIs.io includes 1 Spectral governance ruleset.

Kelvin’s developer surface includes authentication, engineering blog, signup flow, documentation, API reference, support, and 14 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

42.1/100 developing ▬ flat Agent 25/100 agent aware Front door AI 1/6 silent saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessEnterprise

2 published contracts 3 Agent Skills

Company Energy Energy Efficiency Home Renovation Construction Artificial Intelligence Lead Generation Sales Enablement France Sustainability

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 42.1/100 · developing

Contract Quality 9.1 / 19

Developer Ergonomics 7.1 / 15

Access Clarity 5.1 / 15

Operational Transparency 1.5 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 4.8 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 25/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 0 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Energy & Utilities regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)

8 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Access Clarity scores 34.2 — up to +13.2 composite points
Contract Quality scores 48.4 — up to +12.9 composite points
Operational Transparency scores 15.8 — up to +10.9 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/kelvin/apis.yml: open an issue on github.com/api-evangelist/kelvin to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Construction and AEC	undeclared	-	-	-
Franchise Registries (registered franchisors, IFA, POS franchise partners)	undeclared	-	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 1

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OpenAPI

measured — observed by APIs.io (published)

APIs 4

Individual APIs this provider publishes, each with its own machine-readable definition.

Kelvin Documents API

Endpoints pour consulter les documents générés pour une simulation

Kelvin Qualification API

Endpoints disponibles dans l'offre Qualification

Kelvin Simulateur API

Endpoints disponibles dans l'offre Simulateur

Kelvin Simulations API

The Simulations API from Kelvin — 2 operation(s) for simulations.

Open Collections 2

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

kelvin API

OPEN COLLECTION

kelvin API

OPEN COLLECTION

Agent Skills 3

Packaged agent skills for driving this provider's APIs from an AI assistant.

Generate a quote and the renovation paperwork

AGENT SKILL

Run an energy-renovation simulation from an address

AGENT SKILL

Find a dwelling's DPE and attach it to a simulation

AGENT SKILL

Kelvin API pricing

Pricing Plans 1

Published pricing tiers and plan structures.

Kelvin Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Kelvin Rate Limits

0 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Kelvin Finops

FINOPS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Kelvin API Rules

61 rules · 56 errors 2 warnings 3 info

SPECTRAL

OpenAPI Overlays 1

Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.

Kelvin Api Overlay

12 actions · documentation · kelvin-api-openapi.yml

DERIVED

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Kelvin Authentication

http · 1 scheme

SECURITY

Kelvin Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Kelvin Scopes

1 scope

1 scopes

SCOPES

Resources

Get Started 3

Portal, sign-up, and the first successful call

SignUp

SignUp

Login

DeveloperPortal

DeveloperPortal

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

X-MCPServerCandidate

X-MCPServerCandidate

AgentSkill

AgentSkill

LLMsTxt

LLMsTxt

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Components

Components

Access & Security 2

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

RateLimits

RateLimits

Support

Support

Commercial 4

Pricing, plans, and the legal terms of use

PrivacyPolicy

TermsOfService

LegalNotice

Plans

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: kelvin
name: Kelvin
description: Kelvin (kelvin°) is a Paris-based startup, founded in 2023 and backed by Seedcamp, building an AI-powered commercial
  platform for the home energy-renovation industry in France. Its tools help RGE-certified artisans, renovation contractors,
  general contractors, CEE delegatees and trade platforms find and qualify renovation prospects, generate leads through embeddable
  address-based simulators, automatically compute energy-efficiency scenarios and government aids (MaPrimeRenov / CEE) with
  remaining customer cost, and assemble complete financing packages. The AI is trained by thermal engineers and architects
  and uses open data plus computer vision to assess buildings without a recent DPE. More than 4,000 artisans and sales reps
  use Kelvin to prospect, prepare appointments and quote work.
url: https://raw.githubusercontent.com/api-evangelist/kelvin/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- seedcamp
x-tier: profiled
x-tier-reason: 'Promoted from stub 2026-08-14: a real, live, versioned OpenAPI 3.1.0 contract (kelvin API v3, 25 operations)
  was found published at https://app.go-kelvin.com/api/docs and harvested, along with v2.'
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: enterprise
  onboarding: sales
  trial: false
  try_now: false
  public: false
  label: Enterprise · Requires approval
  confidence: high
  source:
  - https://app.go-kelvin.com/api/docs
  - https://www.go-kelvin.com/demo-produit
  - https://www.go-kelvin.com/creer-un-compte-kelvin
  note: The API reference is fully public and requires no login, but access to the API is not. No price is published anywhere
    (/tarifs, /prix and /pricing all 404), there is no self-serve key issuance, and credentials are per-team keys prefixed
    team-api-key- that kelvin provisions. Every commercial path funnels to a demo request or contact form. Free public calculators
    exist on the marketing site but are not API access.
  generated: '2026-08-14'
  method: searched
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-08-14'
image: https://cdn.prod.website-files.com/6655caeb6e3835fd7ee50dd6/67a1271dde24f8ccdf843524_Kelvin-Wordmark.svg
tags:
- Company
- Energy
- Energy Efficiency
- Home Renovation
- Construction
- Artificial Intelligence
- Lead Generation
- Sales Enablement
- France
- Sustainability
apis:
- aid: kelvin:kelvin-documents-api
  name: Kelvin Documents API
  description: Endpoints pour consulter les documents générés pour une simulation
  humanURL: https://app.go-kelvin.com/api/docs
  baseURL: https://app.go-kelvin.com
  tags:
  - Documents
  properties:
  - type: OpenAPI
    url: openapi/kelvin-documents-api-openapi.yml
  - type: Documentation
    url: https://app.go-kelvin.com/api/docs
  - type: APIReference
    url: https://app.go-kelvin.com/api/docs
  - type: Authentication
    url: authentication/kelvin-authentication.yml
  - type: OAuthScopes
    url: scopes/kelvin-scopes.yml
  - type: Conventions
    url: conventions/kelvin-conventions.yml
  - type: ErrorCatalog
    url: errors/kelvin-problem-types.yml
  - type: DataModel
    url: data-model/kelvin-data-model.yml
  - type: Lifecycle
    url: lifecycle/kelvin-lifecycle.yml
  - type: ChangeLog
    url: changelog/kelvin-changelog.yml
  - type: RateLimits
    url: rate-limits/kelvin-rate-limits.yml
  - type: Conformance
    url: conformance/kelvin-conformance.yml
- aid: kelvin:kelvin-qualification-api
  name: Kelvin Qualification API
  description: Endpoints disponibles dans l'offre Qualification
  humanURL: https://app.go-kelvin.com/api/docs
  baseURL: https://app.go-kelvin.com
  tags:
  - Qualification
  properties:
  - type: OpenAPI
    url: openapi/kelvin-qualification-api-openapi.yml
  - type: Documentation
    url: https://app.go-kelvin.com/api/docs
  - type: APIReference
    url: https://app.go-kelvin.com/api/docs
  - type: Authentication
    url: authentication/kelvin-authentication.yml
  - type: OAuthScopes
    url: scopes/kelvin-scopes.yml
  - type: Conventions
    url: conventions/kelvin-conventions.yml
  - type: ErrorCatalog
    url: errors/kelvin-problem-types.yml
  - type: DataModel
    url: data-model/kelvin-data-model.yml
  - type: Lifecycle
    url: lifecycle/kelvin-lifecycle.yml
  - type: ChangeLog
    url: changelog/kelvin-changelog.yml
  - type: RateLimits
    url: rate-limits/kelvin-rate-limits.yml
  - type: Conformance
    url: conformance/kelvin-conformance.yml
- aid: kelvin:kelvin-simulateur-api
  name: Kelvin Simulateur API
  description: Endpoints disponibles dans l'offre Simulateur
  humanURL: https://app.go-kelvin.com/api/docs
  baseURL: https://app.go-kelvin.com
  tags:
  - Simulateur
  properties:
  - type: OpenAPI
    url: openapi/kelvin-simulateur-api-openapi.yml
  - type: Documentation
    url: https://app.go-kelvin.com/api/docs
  - type: APIReference
    url: https://app.go-kelvin.com/api/docs
  - type: Authentication
    url: authentication/kelvin-authentication.yml
  - type: OAuthScopes
    url: scopes/kelvin-scopes.yml
  - type: Conventions
    url: conventions/kelvin-conventions.yml
  - type: ErrorCatalog
    url: errors/kelvin-problem-types.yml
  - type: DataModel
    url: data-model/kelvin-data-model.yml
  - type: Lifecycle
    url: lifecycle/kelvin-lifecycle.yml
  - type: ChangeLog
    url: changelog/kelvin-changelog.yml
  - type: RateLimits
    url: rate-limits/kelvin-rate-limits.yml
  - type: Conformance
    url: conformance/kelvin-conformance.yml
- aid: kelvin:kelvin-simulations-api
  name: Kelvin Simulations API
  description: The Simulations API from Kelvin — 2 operation(s) for simulations.
  humanURL: https://app.go-kelvin.com/api/docs
  baseURL: https://app.go-kelvin.com
  tags:
  - Simulation
  tags_raw:
  - Simulations
  properties:
  - type: OpenAPI
    url: openapi/kelvin-simulations-api-openapi.yml
  - type: Documentation
    url: https://app.go-kelvin.com/api/docs
  - type: APIReference
    url: https://app.go-kelvin.com/api/docs
  - type: Authentication
    url: authentication/kelvin-authentication.yml
  - type: OAuthScopes
    url: scopes/kelvin-scopes.yml
  - type: Conventions
    url: conventions/kelvin-conventions.yml
  - type: ErrorCatalog
    url: errors/kelvin-problem-types.yml
  - type: DataModel
    url: data-model/kelvin-data-model.yml
  - type: Lifecycle
    url: lifecycle/kelvin-lifecycle.yml
  - type: ChangeLog
    url: changelog/kelvin-changelog.yml
  - type: RateLimits
    url: rate-limits/kelvin-rate-limits.yml
  - type: Conformance
    url: conformance/kelvin-conformance.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: RateLimits
  url: rate-limits/kelvin-rate-limits.yml
- type: Overlay
  url: overlays/kelvin-api-overlay.yaml
- type: X-MCPServerCandidate
  url: mcp/kelvin-mcp.yml
  note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list derived
    from the published API contracts, not an existing server. The scorer already read the manifest and reported mcp_server
    correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
- type: AgentSkill
  url: skills/_index.yml
- type: Authentication
  url: authentication/kelvin-authentication.yml
- type: Website
  url: https://go-kelvin.com
- type: Blog
  url: https://go-kelvin.com/ressources
- type: SignUp
  url: https://go-kelvin.com/creer-un-compte-kelvin
- type: Login
  url: https://app.go-kelvin.com/users/sign_in
- type: PrivacyPolicy
  url: https://go-kelvin.com/gestion-des-donnees
- type: LLMsTxt
  url: llms/kelvin-llms.txt
- type: DomainSecurity
  url: security/kelvin-domain-security.yml
- type: DeveloperPortal
  url: https://app.go-kelvin.com/api/docs
- type: Documentation
  url: https://app.go-kelvin.com/api/docs
- type: APIReference
  url: https://app.go-kelvin.com/api/docs
- type: Support
  url: https://go-kelvin.com/demande-de-contact
- type: TermsOfService
  url: https://go-kelvin.com/conditions-de-vente
- type: LegalNotice
  url: https://go-kelvin.com/mentions-legales
- type: Components
  url: components/kelvin-components.yml
- type: Plans
  url: plans/kelvin-plans-pricing.yml
x-artifacts-without-pointer:
  note: These artifacts document a verified ABSENCE. They are deliberately left unwired, because the canonical pointer asserts
    the provider serves the surface and this provider does not.
  files:
  - path: well-known/kelvin-well-known.yml
    reason: No /.well-known/ document on either host — 404 on go-kelvin.com, soft-200 HTML error page on app.go-kelvin.com.
      No WellKnown or SecurityTxt pointer.
  - path: packages/kelvin-packages.yml
    reason: Zero first-party client libraries on any registry, and no GitHub organisation. No Packages or SDKs pointer.
x-enrichment:
  date: '2026-08-14'
  status: enriched
  artifacts_added: 23
  pass: local-v1
  note: 'Contract discovery found the kelvin API. The spec is not served at any /openapi.json-style URL — every such path
    on both hosts returns the Rails application error page — it is embedded as Redoc state in the docs page at https://app.go-kelvin.com/api/docs,
    where a version selector exposes v3 and v2. Both were extracted verbatim. Ownership verified: info.title "kelvin API",
    servers[] default host app.go-kelvin.com, bearer keys prefixed team-api-key-, and the docs URL is cited by kelvin''s own
    resources pages.'

Kelvin API — frequently asked questions

Does Kelvin have an API?

Yes. APIs.io lists 4 APIs from Kelvin, including Kelvin Documents API, Kelvin Qualification API and Kelvin Simulateur API, and 1 more.

Is there an OpenAPI specification for the Kelvin API?

Yes. APIs.io indexes 4 OpenAPI specifications for Kelvin, each linked for download from this page.

How do I authenticate with the Kelvin API?

Kelvin uses bearer-token authentication (http · 1 scheme). The details are profiled on APIs.io as Kelvin Authentication.

Is the Kelvin API ready for AI agents?

Kelvin has a Kin Score of 42.1 out of 100 (developing) and an Agent Readiness score of 25.0 (agent-aware), scored by API Evangelist on 2026-11-06.

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