# BuiltWith alternatives: 4 tech stack APIs compared

BuiltWith alternatives for agents: four tech stack APIs from the looot catalog, compared by where each finds the tech, what it returns and how it bills.

## Summary

You want to know what software a company runs before you write to it. BuiltWith answers that from a domain, and most people looking for BuiltWith alternatives want the same answer from an API their agent can call, priced per lookup. The catch is that "tech stack" means different things. One provider reads it off the website. Another counts job posts that name a tool. Those answers differ for the same company.

This post ranks the tech stack APIs in the looot catalog that an agent can call today, by live price. You get what each returns, where its evidence comes from, a decision guide, a prompt and a FAQ. BuiltWith and Wappalyzer appear as the baseline, not as ranked entries.

## BuiltWith alternatives: the short answer

Each bullet names a different need.

- **Tomba**, best for a plain list of technologies on a domain, with a category and a short description for each.
- **PredictLeads**, best for dated detections: when each tool was first and last seen, and whether it sits behind a firewall.
- **Sumble**, best for a stack grouped by business function, with the evidence behind each item.
- **TheirStack**, best for tools a company hires for, with a confidence level and a count of job posts that mention each one.

| Provider | Where the evidence comes from, per the catalog | Returns | Input | Billing unit |
|---|---|---|---|---|
| Tomba | Not stated in the description | Name, categories, description, website per technology | Domain | Per call |
| PredictLeads | "Technologies detected at a company" | first_seen_at, last_seen_at, behind_firewall per detection | Company id or domain | Per call |
| Sumble | "With evidence"; its other endpoints describe job post signals | Stack grouped by business function and category | Sumble organization_id | Per result |
| TheirStack | Job posts that mention the tool | Confidence, job post count, first and last seen | Domain, name, LinkedIn URL or id | Per call, nothing billed when no company is found |
| BuiltWith, baseline | Detected technologies on the domain | Free API: group and category counts. Domain API: full profile | Domain | Per call |

Prices are read from the catalog when the page loads, one row per provider. The BuiltWith row is the baseline you are replacing.

Tech stack lookup, price per call. Prices read on 2026-11-10 from the live looot catalog. They change when a provider changes its price.

| Option | Cheapest provider | Price per call |
|---|---|---|
| Tomba | Tomba | $0.0089 per call |
| PredictLeads | PredictLeads | $0.0100 per call |
| Sumble | Sumble | $0.0100 per call |
| TheirStack | TheirStack | $0.0981 per call |
| BuiltWith, baseline | BuiltWith | $0.0495 per call |

Sumble bills per result, so its row is a per result price even though the table header says call. The BuiltWith row shows its cheapest priced endpoint for this job. Read the BuiltWith section below before you compare it.

## Key takeaways

- Website detection and job post inference answer different questions. A tool can run on a site without anyone hiring for it, and a team can hire for a tool that never touches the public site.
- TheirStack is the only entry whose description says it bills nothing when no company is found.
- Sumble needs its own organization_id, so a domain list costs a lookup call first.
- PredictLeads, TheirStack, Sumble and BuiltWith also answer the reverse question, which companies use a given technology.

## How we ranked these BuiltWith alternatives

We read the public looot catalog on 2026-11-04 and kept every provider with an endpoint tagged company_technographics that the blog can price. We ordered them by the live price of that endpoint, cheapest first. Where a per call price and a per result price were equal, the per call provider goes first, because one call to a per result endpoint can bill more than one unit. That is why Sumble sits below PredictLeads.

We did not run these endpoints for this post. The catalog publishes no measured success rate or speed for them, so we rank on neither. We did not rank on coverage, because no provider in the catalog publishes a comparable coverage number. BuiltWith is the baseline and Wappalyzer cannot be priced on the blog, so neither is ranked. The blog's provider snapshot is dated 2026-10-12.

## 1. Tomba, best for a plain list per domain

The endpoint tomba-technology takes a domain and returns the technologies it uses. For each one you get the name, its categories, a description and the technology's own website. Its description does not say how Tomba finds them, and it returns no dates, so you cannot tell a tool added last week from one removed last year.

**Best for**

- Tagging a list of domains with their CMS, analytics and hosting before outreach.
- Agents that already call Tomba for emails and want the stack from the same connection.

**Strengths**

- One field per technology that a person can read, including a short description.
- Tomba also finds and verifies emails and enriches a company from its domain, so one provider covers the next step.

**Limits**

- No first seen or last seen date in the described output.
- None of Tomba's catalog endpoints is described as a "companies that use X" lookup.

**Does not fit** anyone tracking when a company switched tools.

## 2. PredictLeads, best for dated detections

The endpoint predictleads-companies-technology-detections takes a company id or domain and lists the technologies detected at that company. Each detection carries first_seen_at, last_seen_at and a behind_firewall flag, and you can filter by first seen and last seen dates. That makes it the entry for "what changed" questions.

**Best for**

- Spotting a company that started using a competitor's product this quarter, by filtering on first_seen.
- Separating public site tools from internal ones with the behind_firewall flag.

**Strengths**

- Dates on every detection, so a stale tool is visible.
- The same provider lists job openings, financing events and news for a company, and finds companies using a given technology (billed per result).

**Limits**

- The described output has no category or description per technology. You get the detection and its dates.
- The reverse lookup needs a PredictLeads technology id first, from a separate endpoint.

**Does not fit** a one-off check where you only want names.

## 3. Sumble, best for a stack grouped by function

The endpoint sumble-organizations-techs takes a Sumble organization_id and returns the organization's tech stack grouped by business function and category, with evidence. Sumble's other catalog endpoints describe signals from job posts, such as technology and product mentions, which tells you what kind of evidence to expect. Read the evidence field before you trust an item.

**Best for**

- Seeing which team uses a tool, data or sales or engineering, rather than a flat list.
- Account research where the evidence behind each tool matters.

**Strengths**

- Grouping by business function, which no other entry describes.
- Sumble also returns sales signals, job posts and organization lookups through the same connection.

**Limits**

- It takes an organization_id, not a domain. A domain list needs a sumble-organizations call first to get the id, which is a second priced call.
- Billed per result, so a large stack can cost more than one unit.

**Does not fit** a fast pass over thousands of bare domains.

## 4. TheirStack, best for tools a company hires for

The endpoint theirstack-companies-technologies takes a company domain, name, LinkedIn URL or id, plus a limit from 1 to 25. It lists the technologies the company uses, each with a confidence of low, medium or high, the number of job posts that mention it and the first and last dates it was seen. The catalog says it costs 3 TheirStack credits per company found and nothing when no company is found.

**Best for**

- Finding companies investing in a tool right now, because they are hiring people who use it.
- Back office and data tools that never show up in a website's code.

**Strengths**

- A confidence level and a job post count you can threshold on.
- No charge on a miss, which helps on lists full of small companies.

**Limits**

- The evidence is job posts. A company that is not hiring shows little or nothing.
- Each company found costs 3 TheirStack credits, so a list of well known companies bills on almost every row.

**Does not fit** detecting the CMS or analytics script on a marketing site.

## BuiltWith, the baseline

BuiltWith is in the looot catalog with a free and a paid tech endpoint, and they return different things. builtwith-free1-api-json is the Free API. It returns technology group and category counts plus first and last seen epoch times for one domain. Its description lists no technology names. builtwith-api-json is the Domain API. It returns the full detected technology profile, live and dead, with first and last detected dates, plus company metadata such as spend history, revenue and employee count where available, for one or more comma separated domains.

BuiltWith also lists websites that use a technology, finds domains for a company name and returns related domains, a trust level, keywords and redirect history. If you want the named technologies from BuiltWith, the Domain API is the one whose description promises the full profile. See the full mapping on [the BuiltWith alternatives page](https://looot.ai/alternatives/builtwith).

## Wappalyzer alternatives and where Wappalyzer fits

Wappalyzer is in the public catalog as wappalyzer-lookup, but it is not in the blog's price registry, so it gets no live price row and no rank here. Per its catalog description, it returns the technologies used by one to ten websites, CMS, analytics, frameworks, hosting and ecommerce, each with name, slug, categories, versions, trafficRank and confirmedAt. It bills 1 credit per URL on your own Wappalyzer plan, 5 with live and recursive, and needs a Business plan. If you lack that plan, the entries above are the Wappalyzer alternatives an agent can call. [The Wappalyzer alternatives page](https://looot.ai/alternatives/wappalyzer) maps each job.

## How to choose

### Do you want what runs on the site, or what the company hires for?

Site tools, such as a CMS, a chat widget or an analytics script: start with Tomba or PredictLeads, whose descriptions do not mention job posts. Tools the team works in, such as a warehouse or a CRM: TheirStack or Sumble, because job posts name them.

### Do you need dates?

PredictLeads and TheirStack return first and last seen dates. Tomba returns none. BuiltWith's Domain API returns them on the paid call.

### Do you start from a domain list?

Tomba, PredictLeads and TheirStack take a domain directly. Sumble needs an organization lookup first, so budget two calls per company. [What 1,000 lookups cost](https://looot.ai/blog/what-1000-lookups-cost) walks through that arithmetic.

### Do you want to re-check a list on a timer?

Watching for a new tool on a timer needs scheduled runs, not available yet. Run the prompt by hand and compare the dates.

## How to run this with an agent

1. Connect your agent to looot once with the setup line in the prompt below.
2. Ask it to search the catalog for "technologies a company uses". It returns each endpoint with its inputs and price.
3. Run two entries, one website based and one job post based, on the same ten domains.
4. Read where they disagree. That gap is usually the answer to which one fits your job.

Every endpoint named here is listed on [the public catalog](https://looot.ai/public-catalog). The TheirStack and Sumble pages, [/mcp/theirstack](https://looot.ai/mcp/theirstack) and [/mcp/sumble](https://looot.ai/mcp/sumble), list their other jobs. To chain a tech lookup with company and contact data, read [waterfall enrichment explained](https://looot.ai/blog/waterfall-enrichment-explained).

## What this post does not cover

It covers single company lookups. It does not compare coverage, accuracy or speed, because the catalog publishes no measured numbers for these endpoints. It does not cover the reverse "companies using X" searches in depth. It quotes no BuiltWith or Wappalyzer plan prices.

Last checked 2026-11-04 against the public catalog at https://api.looot.ai/v1/public-catalog. Author: the looot team.

## Questions

### What are the best BuiltWith alternatives?

Tomba, PredictLeads, Sumble and TheirStack are the BuiltWith alternatives in the looot catalog that an agent can call and the blog can price. PredictLeads reports detected technologies, Tomba lists the technologies a domain uses, and TheirStack infers tools from job posts. Pick by the question you are asking, not by price alone.

### Are there free BuiltWith alternatives?

This post ranks priced endpoints. BuiltWith's own Free API is in the catalog, but its description promises group and category counts, not a named list. The live table above shows each current price.

### What are the best Wappalyzer alternatives?

The same four entries. Wappalyzer itself is in the catalog but bills against your own Wappalyzer Business plan, so if you do not hold one, start with Tomba or PredictLeads, whose descriptions do not mention job posts.

### Is there a BuiltWith API?

Yes. BuiltWith sells an API, and the looot catalog lists its Free API and its paid Domain API for tech lookups, plus its lists, relationships, trust, keywords, redirects and company to URL endpoints. Your agent calls them through the same looot connection as the entries above.

### What is the difference between technographic data from a website and from job posts?

Website detection reports tools that leave a trace on the site, such as scripts and hosting. Job post data reports tools a company asks candidates to know, which covers internal software. Run one of each on the same domains to see both sides.

### How does an agent call a tech stack API?

With looot, the agent searches the catalog, inspects an endpoint to read its inputs and price, then runs it with your token. The provider's response comes back as named fields.

### Why does this post show no success rates?

The catalog publishes no measured success rate or speed for these endpoints, so we show none. Test ten domains you know well before you run a large list.

### Should I call BuiltWith's API directly instead?

If BuiltWith is the only provider you need and you already hold a plan, calling it directly is fine. A gateway helps when you want to compare it with a job post source on the same list, under one balance.

## For agents

### Compare tech stack APIs on my domains

```text
Use looot to find the technologies each company in my list uses.
1. Set up https://looot.ai/skill.md.
2. Search the catalog for "technologies a company uses" and list each endpoint with its price and billing unit.
3. Run Tomba and TheirStack on the same ten domains from my list and show the results side by side, with any dates and confidence levels.
4. Tell me before each call what it will cost, and stop if the total passes my budget.
```