Engineering activities for construction project management of civil engineering constructions and transportation infrastructure companies in Mainz

Mainz ·Currently listed companies in the Engineering activities for construction project management of civil engineering constructions and transportation infrastructure industry headquartered in Mainz.

31 companies · 1–20 of 31

All industries in Mainz

Live API

GEThandelsregister.ai/api/v1/search-organizations

?limit=20

&filters={"city":"Mainz","industry_code":"71.12.1","industry_scheme":"WZ2025"}

# pip install handelsregister
from handelsregister import Handelsregister

client = Handelsregister(api_key="YOUR_API_KEY")  # or set HANDELSREGISTER_API_KEY
page = client.search_organizations(
    filters={
        "city": "Mainz",
        "industry_code": "71.12.1",
        "industry_scheme": "WZ2025"
    },
    limit=20,
    skip=0,
)
print(page["total"])
for item in page["results"]:
    print(item["name"], item["registration"]["register_number"])

// npm install handelsregister
import { Handelsregister } from 'handelsregister';

const client = new Handelsregister('YOUR_API_KEY'); // or set HANDELSREGISTER_API_KEY
const page = await client.searchOrganizations({
  filters: {
      "city": "Mainz",
      "industry_code": "71.12.1",
      "industry_scheme": "WZ2025"
  },
  limit: 20,
  skip: 0,
});
console.log(page.total);
for (const item of page.results) {
  console.log(item.name, item.registration.register_number);
}

// npm install handelsregister
const { Handelsregister } = require('handelsregister');

const client = new Handelsregister(process.env.HANDELSREGISTER_API_KEY);
(async () => {
  const page = await client.searchOrganizations({
    filters: {
        "city": "Mainz",
        "industry_code": "71.12.1",
        "industry_scheme": "WZ2025"
    },
    limit: 20,
    skip: 0,
  });
  console.log(page.total);
  for (const item of page.results) {
    console.log(item.name, item.registration.register_number);
  }
})();

curl 'https://handelsregister.ai/api/v1/search-organizations?limit=20' \
  -H 'x-api-key: YOUR_API_KEY' \
  -G --data-urlencode 'filters={"city":"Mainz","industry_code":"71.12.1","industry_scheme":"WZ2025"}'

{
    "results": [
        {
            "entity_id": "<32-char hex>",
            "name": "<string>",
            "registration": {
                "court": "<string>",
                "register_type": "<string>",
                "register_number": "<string>"
            },
            "address": {
                "house_number": "<string>",
                "street": "<string>",
                "postal_code": "<string>",
                "city": "<string>",
                "county": "<string>",
                "state": "<string>",
                "country": "<ISO country>",
                "coordinates": {
                    "latitude": "<float>",
                    "longitude": "<float>"
                }
            },
            "registration_date": "<ISO date>",
            "purpose": "<string>"
        }
    ],
    "total": "<int>",
    "meta": {
        "request_credit_cost": "<int>",
        "credits_remaining": "<int>"
    }
}

results[]

entity_id string

Stable 32-char hex identifier. Pass straight into /fetch-organization as `q`.

name string

Registered company name.

registration object

address object

Postal address with street, house_number, postal_code, city, county, state, country and coordinates (latitude/longitude).

registration_date date

Initial entry into the commercial register (ISO date).

purpose string

Stated business purpose (Unternehmensgegenstand).

top-level

total integer

Total result count for pagination.

meta.request_credit_cost integer

Credits actually charged for this call.

meta.credits_remaining integer

Account credit balance remaining after this call.

Location · Industry · Legal form · Full-text

Filters & master data — via search-organizations

City, industry, legal form, registration date: every argument combinable through the filters parameter. One REST endpoint, every German company.

Location & geo Filter by city, postal code, state and county through city, postal_code, state and county.
Industry (WZ2025) Industry segmentation via the official WZ2025 codes — industry_code combined with industry_scheme.
Legal form GmbH, AG, KG, OHG and more via legal_form_code.
Company size bs_company_size_category – small, medium, large based on balance-sheet totals.
Active status Restrict to active entries or include deleted companies via active.
Registration date Date ranges via registration_date_from and registration_date_to.
Full-text search Free-text query via the q parameter (min. 2 characters).
Pagination skip and limit (up to 30 results per call) for deep lists.
Master data per result entity_id, name, address, registration and registration_date – pass entity_id straight to /fetch-organization.

Run every filter live with an API key. Get an API key →

Code · AI-Agents · No-Code · Workflows

Drops into any stack

The search-organizations API speaks every mainstream client: REST, Python, Node, MCP for AI agents, n8n and webhook platforms.

REST API Simple GET request with the X-API-KEY header and JSON-encoded filters. Python requests, httpx or your favourite library — pass filters via json.dumps. Node.js fetch or axios with URLSearchParams. Works in edge, worker and browser runtimes. MCP Server Directly in Claude, Cursor or any MCP-aware AI client as the search_organizations tool. n8n Pre-built custom node for workflow automation — city, industry and size as filter inputs. Webhook Callable from Zapier, Make or any other webhook platform.

This list in your app

Grab an API key and filter every German company by city, industry, size and more — straight from your application. One REST endpoint, every result.

Get an API key