# CompanyStack, £29 monthly: Business verification API

> Pass, refer, fail or unable to check, with reason codes, stored with the date it ran, and a PDF certificate that reproduces the check with a reference anyone can verify.

CompanyStack's Starter plan for the business verification API costs $386.715 per 1,000 companies. We check each provider's docs for 11 fields. CompanyStack's docs list 2: Registered name, Entity number.
£290.00 per 1,000 companies is $386.715 at the European Central Bank's rate of $1.3335 for £1.
We haven't run CompanyStack through [our business verification API benchmark](https://datacircle.dev/best-business-verification-api.txt) yet.
We rank 1,735 plans for business verification APIs by price. Half the plans cost $7.895 or less per 1,000 companies. This plan costs less per 1,000 companies than 7% of the 1,735 plans.
[SafeDeal's ₸50,000 (about $110) monthly plan](https://datacircle.dev/business-verification-apis/safedeal/50000-monthly/llms.txt) is the cheapest paid plan per 1,000 companies. SafeDeal's business verification API costs nothing beyond the plan price. SafeDeal's plan covers companies in Kazakhstan only. [ApiZero's CNY 399 yearly plan](https://datacircle.dev/business-verification-apis/apizero/cny-399-yearly-diamond-membership-get-api-company-search/llms.txt) costs the least for 10,000 companies a month: about $4.97.
[Scoris' €19 pack](https://datacircle.dev/business-verification-apis/scoris/19-pack/llms.txt) covers any number of companies in 8 countries only. Scoris' €19 pack costs less up front than SafeDeal's ₸50,000 (about $110) monthly plan.
[GovFiles](https://datacircle.dev/business-verification-apis/govfiles/top-up/llms.txt), [Didit](https://datacircle.dev/business-verification-apis/didit/top-up-from-50/llms.txt) and [CompanyData.com](https://datacircle.dev/business-verification-apis/companydata-com/249-monthly/llms.txt) are the best business verification API providers in the Datacircle benchmark for companies in any country.

- This page: https://datacircle.dev/business-verification-apis/companystack/29-monthly
- [Business verification API in 2026: the 8 best compared](https://datacircle.dev/best-business-verification-api.txt)
- Get it: https://companystack.co.uk/pricing?product=api&utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing
- Request: `POST https://api.companystack.co.uk/kyb/check`
- API key: with the plan, on https://companystack.co.uk/pricing?product=api&utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing
- Its API docs: https://companystack.co.uk/docs/reference?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing#op/POST/kyb/check
- Sold by: CompanyStack (https://companystack.co.uk?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing)
- Checked: 2026-11-10

## In the answer

- Completeness: 18%
- Registered name: ✓
- Entity number: ✓

## Price

- $ per 1,000 companies: $386.715
- Per: call
- Billing: monthly
- $ a month: $38.67

## Aggregators

- Aggregators: none

## Charges

- Also pays for: Get the Automated analyst view of a company · Company report (PDF) · 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 · Group structure: who controls whom · Company health score · Financial indicators · Filed accounts, year by year · Get company officers (cached) · Persons of significant control · Get filing history (cached) · Radius search: every company within a distance, nearest first · Companies by SIC code · Full real-time company report · Screen a company against sanctions lists · Find companies by sector, place, age and size - or lookalikes

## In their words

- Their pitch: Pass, refer, fail or unable to check, with reason codes, stored with the date it ran, and a PDF certificate that reproduces the check with a reference anyone can verify.

## Data

- Freshness: stored
- Countries: United Kingdom
- 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: £29
- You get: 100 requests a month
- Enough for: 100 calls a month

## Rate limit

- Per day: 10,000
- Per second: 1
- Batch: 1

## Speed

- Answer: in the call

## The call

- You send: company_number. Optional: expected_name, expected_postcode, expected_pscs, expected_directors, include_identity_verification, min_age_months, address_density_threshold, reference
- Method: POST
- Path: /kyb/check

## About the plan

- Plan: Starter
- 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 35 fields the plan's answer can hold

check ID, company number, company name, reference, outcome, summary, reason codes, warnings, checks, check result, check reason code, check message, check evidence, sanctions verdict, sanctions officers status, sanctions summary, sanctions screened at, sanctions lists, sanctions subjects, sanctions not screened, sanctions matches, charges available, charges total, charges outstanding, charges part satisfied, charges satisfied, charges other, charges as at, charges source, charges reason, charges note, data as of, checked at, disclaimer, notice

## CompanyStack's plans (5)

- [CompanyStack, £29 monthly](https://datacircle.dev/business-verification-apis/companystack/29-monthly/llms.txt): $386.715 per 1,000, 18% complete, stored
- [CompanyStack, £99 monthly](https://datacircle.dev/business-verification-apis/companystack/99-monthly/llms.txt): $132.017 per 1,000, 18% complete, stored
- [CompanyStack, £288 yearly](https://datacircle.dev/business-verification-apis/companystack/288-yearly/llms.txt): $320.04 per 1,000, 18% complete, stored
- [CompanyStack, £984 yearly](https://datacircle.dev/business-verification-apis/companystack/984-yearly/llms.txt): $109.347 per 1,000, 18% complete, stored
- [CompanyStack, contact us](https://datacircle.dev/business-verification-apis/companystack/contact-us/llms.txt): 18% complete, stored

## CompanyStack's calls for this API (1)

- `POST /kyb/check`: [CompanyStack, £29 monthly](https://datacircle.dev/business-verification-apis/companystack/29-monthly/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: business verification API alternatives

- [Houjin Agentic JP, pay as you go, x402 pay per call, POST /report](https://datacircle.dev/business-verification-apis/houjin-agentic-jp/pay-as-you-go-x402-pay-per-call-post-report/llms.txt): $250.00 per 1,000, 36% complete, stored
- [Limitguard, $999 pack, Pro, POST /v1/kyb/check, KYB Check, cached](https://datacircle.dev/business-verification-apis/limitguard/999-pack-pro-post-v1-kyb-check-kyb-check-cached/llms.txt): $250.00 per 1,000, 27% complete, stored
- [OpenCorporates, £6,600 yearly](https://datacircle.dev/business-verification-apis/opencorporates/6600-yearly/llms.txt): $293.37 per 1,000, 55% complete, stored
- [TIN Comply, $2,000 pack, 5,000-Pack, POST /api/v1/validate/company-details-lookup-by-name-address](https://datacircle.dev/business-verification-apis/tin-comply/2000-pack-5000-pack-post-api-v1-validate-company-details-lookup-by-name-address/llms.txt): $400.00 per 1,000, 27% 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=business-verification-api-pricing
- https://companystack.co.uk/docs?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing
- https://companystack.co.uk/docs/reference?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing
- https://companystack.co.uk/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing
- https://companystack.co.uk/pricing?product=api&utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing
- https://companystack.co.uk/terms?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=business-verification-api-pricing