Does the API invent answers?

No. That's the core of the product. Every answer is extracted from a verified diagnostics database and returns its exact source (manual, page, section) plus a confidence score. If Marcel doesn't know, it says so.

What's the difference between REST API and MCP?

REST integrates into your software (CMMS, ERP, apps). MCP plugs the brain directly into your AI agents (Claude, ChatGPT, custom agents) as a native tool. Same database, two access modes.

How long to integrate?

A key in 2 minutes, a first answer in an afternoon. JS/TS and Python SDKs, OpenAPI and MCP server ready to use.

Which brands and product families are covered?

Heat pumps, air conditioning, boilers, stoves & pellets — major market brands (Daikin, Atlantic, Mitsubishi, Viessmann, Saunier Duval, Palazzetti, MCZ…), continuously expanding.

11 languages in production. Query and display in your market language.

Is white-label possible?

Yes, from the Scale tier: your interface, our brain. Dedicated corpus available for manufacturers.

How are requests billed?

By monthly tier (Developer free, Starter €29, Business €149). Beyond the included envelope, top up with prepaid 1,000-request packs (€10 Starter, €7 Business) — no post-paid billing.

I have Marcel Pro — do I need to pay for the API?

App subscription and API are two separate meters. Any signed-in account can activate a free Developer key (500 req/month) to plug Marcel into Claude, ChatGPT, or your tools — ideal for personal MCP use. Beyond that, upgrade to Starter: you're building a product, you're an API customer.

Ask Marcel50,000+ HVAC fixes

REST API · NATIVE MCP · 11 LANGUAGES · MANUFACTURER-SOURCED

THE HVAC TROUBLESHOOTING INFRASTRUCTURE LAYER

OUR BRAIN.
YOUR TOOLS.

The HVAC troubleshooting database powering the AskMarcel app is now an API. Plug 50,000 verified diagnostics — sourced from manufacturer manuals — into your service software, business ERP, or AI agent. One request, one sourced answer. No hallucination, no PDFs, no hotline.

Sourced answers: page, section, value — never invented
REST + native MCP: integrate in an afternoon
JS & Python SDKs, OpenAPI spec and MCP server included

Get an API key Read the docs Talk to the team

curl https://api.askmarcel.app/v1/diagnostic \
  -H "Authorization: Bearer sk_live_…" \
  -d '{ "brand": "Mitsubishi", "model": "Ecodan PUHZ-W85", "error_code": "E7" }'

THE REAL BOTTLENECK

YOUR SOFTWARE KNOWS WHO, WHEN, WHERE.
NOT HOW TO FIX IT.

Your CMMS manages routes. Your ERP handles billing. Your AI agent answers customers. But at the critical moment — the error code on the unit — they all send the technician back to the hotline and 400-page PDFs. The technical data is missing. Building a multi-brand HVAC troubleshooting database in-house takes years of crawling, structuring, and field verification. Or one line of code.

Building in-house = a 3-year project.

Collecting, cleaning, and structuring manuals from dozens of brands is a job in itself. Not a sprint.

Generic AI invents.

An LLM without domain data hallucinates an ohmic value. In the field, a wrong value means a return visit.

The data already exists — elsewhere.

AskMarcel has already crawled, structured, and verified it. You plug it in instead of rebuilding it.

ONE API, THREE PROMISES

MARCEL ANSWERS. YOUR TOOLS ACT.

From raw request to displayed procedure — no hallucination.

Flexible input: code, model, or photo.

Send an error code, model reference, nameplate image in base64, or a natural language question. The API identifies context and normalizes the request. Endpoint POST /v1/diagnostic.

Step 01

The brain: a sourced answer, not a guess.

The API doesn't "generate". It queries 50,000 verified diagnostics from manufacturer manuals. Every answer returns its exact source — manual, page, section — plus a confidence score. That's the anti-hallucination moat.

Step 02

Structured output: ready to display.

Clean JSON: step-by-step procedure, expected values (ohmic, pressure, temperature), spare part reference. Display it as-is in your UI, or pass it to your agent. Ticket closed on first visit.

Step 03

REST FOR YOUR SOFTWARE. MCP FOR YOUR AGENTS.

REST API

To integrate AskMarcel into an existing product.

Simple endpoints: /diagnostic, /search, /models, /brands
Bearer key auth, clear quotas, webhooks
JS/TS and Python SDKs, OpenAPI provided
Ideal for: CMMS, ERP, service portals, field mobile apps

WOW

MCP Server

To give any AI agent real HVAC expertise.

Native MCP server: Claude, ChatGPT, Copilot, custom agents
The agent "calls" Marcel as a tool, with sources
Zero glue code: add the server, the agent can diagnose
Ideal for: service copilots, support chatbots, internal assistants

MCP

{
  "mcpServers": {
    "askmarcel": {
      "url": "https://mcp.askmarcel.app",
      "headers": { "Authorization": "Bearer sk_live_…" }
    }
  }
}

The same verified brain. Two ports. Choose the one that fits your stack.

WHO IT'S FOR, CONCRETELY

Service & maintenance companies

YOUR TECHNICIANS, AUGMENTED — WITHOUT CHANGING TOOLS.

Integrate AskMarcel diagnostics directly into your CMMS or field app. Your technicians keep their interface; they gain sourced answers. ROI is measured in avoided return visits — not licenses.

1h45 → 20 min on the same job (E7 code). +1h25 per breakdown.

Estimate my ROI

Developers & AI agents

GIVE YOUR AGENT REAL DOMAIN EXPERTISE.

A generalist LLM guesses. Plug in the AskMarcel MCP server and your agent cites its sources: manual, page, value. Setup in minutes, not months.

MCP

{
  "mcpServers": {
    "askmarcel": {
      "url": "https://mcp.askmarcel.app",
      "headers": { "Authorization": "Bearer sk_live_…" }
    }
  }
}

Read the MCP docs

ERP / CMMS publishers

THE TECHNICAL LAYER YOUR PRODUCT IS MISSING.

Add an "HVAC diagnostics" feature to your software without building a document database. White-label available: your interface, our brain. Your customers see one product — yours, better.

Discuss a partnership

Manufacturers & distributors

YOUR AFTER-SALES, AVAILABLE 24/7 VIA API.

Expose your product range technical docs in a modern, structured, multilingual channel. Reduce hotline pressure. White-label and dedicated corpus available.

Request a demo

WHY MARCEL, NOT AN LLM ALONE

BUILT FOR THE FIELD, NOT THE HYPE.

50,000 HVAC diagnostics

Structured, from manufacturer docs — not Wikipedia.

Sourced, always.

Page, section, value. Traceable answers, never invented.

All brands

Heat pumps, AC, boilers, stoves & pellets (Daikin, Viessmann, Mitsubishi, Palazzetti…).

11 languages in production

Multi-market rollout without rebuilding.

diagnostics

languages

HVAC families

access modes

ONE PLUG FOR EVERY SCALE

PLUG IN. PAY AS YOU GO.

The Developer tier is free to test. Starter and Business activate self-serve. White-label with the team.

Developer

Testing, POC, personal agents

Free

500 requests/month
REST API + MCP
Full documentation
“Powered by AskMarcel” attribution

Create a free key

Starter

Small teams, integrators

€29/ month excl. VAT

3,000 sourced diagnostics/month
REST + MCP
Webhooks & email support
No attribution required

Choose Starter

Popular

Business

SAV companies, software vendors

€149/ month excl. VAT

20,000 sourced diagnostics/month
SLA & high rate limits
Priority support
Unlimited seats

Choose Business

Scale / White-label

Manufacturers, large vendors

Setup €5–15k+ subscription

Dedicated volume
White-label
Custom corpus
Account manager

Talk to the team

Overage: 1,000-request packs — Starter €10, Business €7 (prepaid, no expiration).
2 months free on annual Starter (€290/year) and Business (€1,490/year).
A request is only counted when the answer is sourced and usable. Errors and empty responses are free.
€29 = 3,000 diagnostics. One avoided return visit pays for 3 months of subscription.
Developer: 500 req/mo, no top-up.

Field technician? See app pricing →

Frequently asked questions

Everything you need to know before plugging in Marcel.

Need technical help? Contact our team

THE BRAIN IS READY. PLUG IT IN.

Create a free key in 2 minutes, or talk to the team for fleet / white-label setup.

Get an API key Book a demo

OUR BRAIN.YOUR TOOLS.

YOUR SOFTWARE KNOWS WHO, WHEN, WHERE.NOT HOW TO FIX IT.