# CompanyStack, free: Company hierarchy API

> Who controls a company and which companies it controls, from the Companies House register of persons with significant control (PSC), as a graph.

CompanyStack's Free plan for the company hierarchy API costs $0.00 per 1,000 companies. We check each provider's docs for 3 fields. CompanyStack's docs list 1: Company.
We haven't run CompanyStack through [our company hierarchy API benchmark](https://datacircle.dev/best-company-hierarchy-api.txt) yet.
This plan is free. We rank 158 plans for company hierarchy APIs by price. Half the plans cost $13.46 or less per 1,000 companies. [See the best free company hierarchy API plan.](https://datacircle.dev/best-company-hierarchy-api.txt)
[CompanyStack's £99 (about $132) monthly plan (/intelligence/group/{number})](https://datacircle.dev/company-hierarchy-apis/companystack/99-monthly-business-get-intelligence-group-number/llms.txt) is the cheapest paid plan per 1,000 companies. CompanyStack's £99 (about $132) monthly plan covers companies in the United Kingdom only. CompanyStack's £99 (about $132) monthly plan covers up to 100,000 companies a day. [CNPJ Aberto's R$449 yearly plan](https://datacircle.dev/company-hierarchy-apis/cnpj-aberto/r-449-yearly-pro-anual-get-api-intelligence-grupo-cnpj/llms.txt) costs the least for 10,000 companies a month: about $7.36.
[GlobalEntity API's €59 monthly plan](https://datacircle.dev/company-hierarchy-apis/globalentity-api/59-monthly/llms.txt) covers any number of companies in 54 countries only. GlobalEntity API's €59 monthly plan costs less up front than CompanyStack's £99 (about $132) monthly plan.
[DiscoLike](https://datacircle.dev/company-hierarchy-apis/discolike/99-monthly/llms.txt), [Bigdata.com](https://datacircle.dev/company-hierarchy-apis/bigdata-com/50-monthly/llms.txt) and [Magellan Data](https://datacircle.dev/company-hierarchy-apis/magellan-data/375-pack-25000-credits-post-v1-corporate-families/llms.txt) are the best company hierarchy API providers in the Datacircle benchmark for companies in any country.

- This page: https://datacircle.dev/company-hierarchy-apis/companystack/free
- [Company hierarchy API in 2026: the 8 best of 110+ compared](https://datacircle.dev/best-company-hierarchy-api.txt)
- Get it: https://companystack.co.uk/pricing?product=api&utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing
- Request: `GET https://api.companystack.co.uk/company/{number}/group-structure`
- API key: with the plan, on https://companystack.co.uk/pricing?product=api&utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing
- Its API docs: https://companystack.co.uk/docs/reference?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing#op/GET/company/{number}/group-structure
- Sold by: CompanyStack (https://companystack.co.uk?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing)
- Checked: 2026-11-10

## In the answer

- Completeness: 33%
- Company: ✓

## Price

- $ per 1,000 companies: $0.00
- Per: call
- Billing: free

## Aggregators

- Aggregators: none

## Charges

- Also pays for: Filed accounts, year by year · Company health score · from the same budget: Search companies · Autocomplete company names · Get company by number · Newly incorporated companies · Search industries by keyword · Get all SIC codes with company counts · One area's business figures

## Overage

- Units cap: hard

## Not found

- $ per 1,000 calls that find nothing: $0.00

## In their words

- Their pitch: Who controls a company and which companies it controls, from the Companies House register of persons with significant control (PSC), as a graph.

## Data

- Freshness: stored
- Countries: United Kingdom
- Full family tree: no
- Keep data: no limit
- Use data: "17.2 While you have an account, we give you a non-exclusive, non-transferable licence to use the Service and its outputs (including API responses, exports and PDF reports) for your internal business purposes. You may keep outputs in your own business records, including after your account ends, and share them with your professional advisers, auditors and regulators." "17.3 You may include limited extracts of our outputs in your own products or publications, provided you credit "CompanyStack" and the original source (for example "Source: Companies House via CompanyStack"). You must not redistribute, resell or publish our data in bulk, or build a competing database from it, without our written agreement." "17.5 You must not present our outputs as a credit rating, as a credit reference about an individual, or as checked, verified, certified or endorsed by us or by Companies House beyond what their labels say." "14.4 If you share or publish our data as clauses 15B and 17 allow, you must keep the attribution statement each source's licence requires (for Companies House data: "Contains public sector information licensed under the Open Government Licence v3.0.") and must not suggest that Companies House or any other source endorses you, us or your use of the data."

## Plan

- Pay: £0
- You get: 1,000 requests a day
- Enough for: 1,000 calls a day

## Rate limit

- Per day: 1,000
- Per second: 0.5 (30 a minute)
- Batch: 1

## Speed

- Answer: in the call

## The call

- You send: number
- Method: GET
- Path: /company/{number}/group-structure

## About the plan

- Plan: Free
- Who can get it: businesses, sole traders, charities, public bodies and other organisations, for use in their trade, business or profession (no consumers), aged 18 or over

## The 79 fields the plan's answer can hold

title, company number, company name, root ID, level, has group, has chart, kind, as at, as shown, source, matching, bands note, completeness note, node ID, node type, node level, node root, node name, node company number, node link, node status, node status label, node born, node registered, node detail, node note, node stop, node other owners, node count, edge ID, edge from, edge to, edge kind, edge natures of control, edge natures text, edge label, edge notified on, edge in cycle, levels above, levels below, companies above, companies below, individuals, other owners, owners, former owners, stop node ID, stop name, stop code, stop text, cycles, notes, omitted former links, omitted unconfirmed links, truncated, company limit, text above, text below, text stops, text notes, layout width, layout height, layout boxes, layout links, narrow layout, former note, share register held, share register as at, share register label, share register note, attribution, notice, locked levels above, locked levels below, locked companies, locked message, upgrade message, upgrade URL

## CompanyStack's plans (6)

- [CompanyStack, free](https://datacircle.dev/company-hierarchy-apis/companystack/free/llms.txt): $0.00 per 1,000, 33% complete, stored
- [CompanyStack, £29 monthly](https://datacircle.dev/company-hierarchy-apis/companystack/29-monthly/llms.txt): $0.129 per 1,000, 33% complete, stored
- [CompanyStack, £99 monthly, Business, GET /company/{number}/group-structure](https://datacircle.dev/company-hierarchy-apis/companystack/99-monthly-business-get-company-number-group-structure/llms.txt): $0.044 per 1,000, 33% complete, stored
- [CompanyStack, £288 yearly](https://datacircle.dev/company-hierarchy-apis/companystack/288-yearly/llms.txt): $0.105 per 1,000, 33% complete, stored
- [CompanyStack, £984 yearly, Business (yearly), GET /company/{number}/group-structure](https://datacircle.dev/company-hierarchy-apis/companystack/984-yearly-business-yearly-get-company-number-group-structure/llms.txt): $0.036 per 1,000, 33% complete, stored
- [CompanyStack, contact us, Enterprise, GET /company/{number}/group-structure](https://datacircle.dev/company-hierarchy-apis/companystack/contact-us-enterprise-get-company-number-group-structure/llms.txt): 33% complete, stored

## CompanyStack's calls for this API (2)

- `GET /company/{number}/group-structure`: [CompanyStack, free](https://datacircle.dev/company-hierarchy-apis/companystack/free/llms.txt)
- `GET /intelligence/group/{number}`: [CompanyStack, £99 monthly, Business, GET /intelligence/group/{number}](https://datacircle.dev/company-hierarchy-apis/companystack/99-monthly-business-get-intelligence-group-number/llms.txt)

## CompanyStack's APIs (4)

- [CompanyStack: company discovery API pricing, 6 plans](https://datacircle.dev/company-discovery-apis/companystack/free/llms.txt)
- [CompanyStack: company enrichment API pricing, 6 plans](https://datacircle.dev/company-enrichment-apis/companystack/free/llms.txt)
- [CompanyStack: company hierarchy API pricing, 6 plans](https://datacircle.dev/company-hierarchy-apis/companystack/free/llms.txt)
- [CompanyStack: business verification API pricing, 5 plans](https://datacircle.dev/business-verification-apis/companystack/29-monthly/llms.txt)

## CompanyStack: company hierarchy API alternatives

- [Firmainfo, contact us, Enterprise, GET /api/v1/companies/{company_id}/subsidiaries](https://datacircle.dev/company-hierarchy-apis/firmainfo/contact-us-enterprise-get-api-v1-companies-company-id-subsidiaries/llms.txt): $0.505 per 1,000, 67% complete, stored
- [DiscoLike, $15,350 yearly](https://datacircle.dev/company-hierarchy-apis/discolike/15350-yearly/llms.txt): $1.20 per 1,000, 67% complete, stored
- [Skrapp, $13,488 yearly, Enterprise 500K, POST /api/v3/companies/bulk-enrich](https://datacircle.dev/company-hierarchy-apis/skrapp/13488-yearly-enterprise-500k-post-api-v3-companies-bulk-enrich/llms.txt): $4.496 per 1,000, 33% complete, stored
- [Canonical, top-up, Extra credits (Pro)](https://datacircle.dev/company-hierarchy-apis/canonical/top-up-extra-credits-pro/llms.txt): $8.00 per 1,000, 67% complete, stored

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-11-10.

- https://companystack.co.uk/developers?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing
- https://companystack.co.uk/docs?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing
- https://companystack.co.uk/docs/reference?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing
- https://companystack.co.uk/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing
- https://companystack.co.uk/pricing?product=api&utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing
- https://companystack.co.uk/terms?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=company-hierarchy-api-pricing