# heade.rs, free: Tech stack API

> Tech stack: its server software, backend, framework, CMS and plugins, UI and CSS libraries, fonts and build tools, with versions where the site gives them away, each checked for end of life (endoflife.date) and known vulnerabilities (OSV)

heade.rs's Free plan for the tech stack API costs $0.00 per 1,000 companies. We check each provider's docs for 13 fields. heade.rs's docs list 2: Technology, Categories.
heade.rs limits how many calls you get but gives no number.
In [our tech stack API benchmark](https://datacircle.dev/best-tech-stack-api.txt), this plan scores 52.3 out of 100. heade.rs ranks 12th of 50 providers.
We rank 488 plans for tech stack APIs by price. Half the plans cost $7.833 or less per 1,000 companies. This plan and 3 others tie for the lowest price per 1,000 companies of the 488 plans. [See the best free tech stack API plan.](https://datacircle.dev/best-tech-stack-api.txt)
[GetProspect's $49 monthly plan](https://datacircle.dev/company-technology-apis/getprospect/49-monthly/llms.txt) covers any number of companies. GetProspect's $49 monthly plan costs less up front than cl0q's $50 monthly plan.
[JobsPipe](https://datacircle.dev/company-technology-apis/jobspipe/149-monthly-growth-post-v1-stack-scan/llms.txt), [DetectZeStack](https://datacircle.dev/company-technology-apis/detectzestack/79-monthly-mega-get-analyze/llms.txt) and [Botoi](https://datacircle.dev/company-technology-apis/botoi/9-monthly/llms.txt) are the best tech stack API providers in the Datacircle benchmark.

- This page: https://datacircle.dev/company-technology-apis/heade-rs/free
- [Company technologies API: tech stack APIs compared](https://datacircle.dev/best-tech-stack-api.txt)
- Get it: https://heade.rs/llms.txt?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- Request: `GET https://heade.rs/api/{query}`
- API key: not needed
- Its API docs: https://heade.rs/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- Sold by: heade.rs (https://heade.rs?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing)
- Checked: 2026-11-10

## In the answer

- Completeness: 15%
- Technology: ✓
- Categories: ✓

## Score

- Overall score: 52.3
- Price score: 100
- Accuracy score: 16
- Cost to get started score: 100
- Bundle score: 0
- Performance score: 10

## Price

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

## Aggregators

- Aggregators: none

## Charges

- Also pays for: nothing else

## Not found

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

## In their words

- Their pitch: Tech stack: its server software, backend, framework, CMS and plugins, UI and CSS libraries, fonts and build tools, with versions where the site gives them away, each checked for end of life (endoflife.date) and known vulnerabilities (OSV)

## Data

- Freshness: live
- Keep data: no API terms
- Use data: no API terms

## Plan

- Pay: $0

## Rate limit

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

## Speed

- Answer: in the call
- Median: 1.48 s

## The call

- You send: query
- Method: GET
- Path: /api/{query}

## About the plan

- Plan: Free
- Who can get it: anyone, with no account or API key

## The 9 fields the plan's answer can hold

domain, technologies, technology category, technology version, technology detection method, technology support status, latest technology version, third-party hosts, rendering mode

## heade.rs's plans (1)

- [heade.rs, free](https://datacircle.dev/company-technology-apis/heade-rs/free/llms.txt): $0.00 per 1,000, 15% complete, live

## heade.rs's calls (1)

- `GET /api/{query}`: [heade.rs, free](https://datacircle.dev/company-technology-apis/heade-rs/free/llms.txt)

## heade.rs's APIs (3)

- [heade.rs: tech stack API pricing, 1 plan](https://datacircle.dev/company-technology-apis/heade-rs/free/llms.txt)
- [heade.rs: domain WHOIS API pricing, 1 plan](https://datacircle.dev/domain-whois-apis/heade-rs/free/llms.txt)
- [heade.rs: IP company lookup API pricing, 1 plan](https://datacircle.dev/ip-company-lookup-apis/heade-rs/free/llms.txt)

## heade.rs: tech stack API alternatives

- [YourAITools, free](https://datacircle.dev/company-technology-apis/youraitools/free/llms.txt): $0.00 per 1,000, 15% complete, live
- [Botoi, free](https://datacircle.dev/company-technology-apis/botoi/free/llms.txt): $0.00 per 1,000, 23% complete, live
- [Companyfacts, free](https://datacircle.dev/company-technology-apis/companyfacts/free/llms.txt): $0.00 per 1,000, 8% complete, live
- [RichAPI, free, Sandbox, POST /web_tech_stack](https://datacircle.dev/company-technology-apis/richapi/free/llms.txt): $0.00 per 1,000, 8% complete, live

## 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://heade.rs?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- https://heade.rs/.well-known/agent-skills/heade-rs/SKILL.md?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- https://heade.rs/api/1.1.1.1?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- https://heade.rs/api/github.com?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- https://heade.rs/llms.txt?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- https://heade.rs/openapi.json?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing
- https://heade.rs/terms?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=tech-stack-api-pricing