canonical: https://jentic.com/apis/builtwith.com/builtwith

# BuiltWith Domain API

Jentic maintains a curated, agent-optimized OpenAPI specification for BuiltWith Domain API, validated against the live API and kept agent-ready. The OpenAPI document BuiltWith publishes itself describes a different BuiltWith API, not these domain lookup operations, so this page is built from the Jentic specification. BuiltWith maintains one of the largest technographic datasets on the web - every detected analytics, ad, framework, hosting, and ecommerce technology powering a domain. The Domain API exposes the same lookup surface as the public site plus relationships, technology trends, keyword detection, redirects, social profiles, and a trust score. Use it to enrich CRM records with tech stack data, build account scoring for outbound, monitor competitor tech changes, or qualify leads by what they currently run.

## For AI agents

Look up the technology stack, social profiles, redirects, and trust score for any domain across 11 BuiltWith endpoints.

## Scope

Does not handle email enrichment, contact data, or company financials - use for domain technology profiles, technographic lists, trends, and trust scores only.

## Capabilities

- Pull the full technology profile detected on a target domain
- Run a lightweight free lookup that returns just core technology categories
- Discover the domain relationships graph linking related and reseller sites
- List every domain that uses a specific technology with the technology list endpoint
- Trace a company name to its primary website with the company-to-URL lookup
- Read trend data showing technology adoption and decline over time
- Fetch the keywords, social media handles, redirects, and trust score for a domain

## Use cases

### Outbound Lead Qualification

Enrich every inbound lead with the tech stack of their company website. The agent calls GET `/v22/api.json` with the lead's domain and parses the technology categories to flag whether the prospect is on a competing platform, a complementary tool, or runs nothing relevant. This routes the lead to the right rep with the right talk track.

Example prompt: For domain example.com, fetch the BuiltWith profile and tag the lead with categories analytics, e-commerce, and marketing-automation tech detected.

### Account Scoring by Tech Fit

Score target accounts based on the technologies they already run. GET `/lists8/api.json` returns every domain using a specific technology, letting you build a scoring model that boosts accounts already running a complementary stack. Combine it with `/trust2/api.json` to filter out low-trust domains automatically.

Example prompt: List domains using Salesforce, score each by trust, and post the top 50 to a Salesforce campaign as target accounts.

### Competitive Tech Monitoring

Track when competitors add or remove a technology. Run a daily script that compares today's GET `/v22/api.json` snapshot for a watchlist of competitor domains against yesterday's, and alert on any changes. The trends endpoint provides longitudinal data so the same workflow can show category-level adoption over months.

Example prompt: Compare today's BuiltWith profile for competitor.com against yesterday's stored snapshot and alert Slack on any added or removed technologies.

### AI Agent Account Researcher via Jentic

An SDR agent connected via Jentic can answer the question what does this prospect run before drafting an outbound email. The agent searches Jentic for tech stack lookup, loads the GET `/v22/api.json` schema, and executes against the operator's vault-stored BuiltWith key, returning a structured tech list ready for prompt context.

Example prompt: Search Jentic for tech stack lookup, load the GET `/v22/api.json` schema, and return the full technology profile for the domain in the user's prompt.

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| GET | `/v22/api.json` | Get full technology profile for a domain |
| GET | `/free1/api.json` | Free-tier lightweight technology lookup |
| GET | `/lists8/api.json` | List domains using a specific technology |
| GET | `/ctu2/api.json` | Company name to URL lookup |
| GET | `/trends3/api.json` | Technology adoption trends |
| GET | `/social2/api.json` | Social media profiles for a domain |
| GET | `/trust2/api.json` | Trust score for a domain |

## Key resources

- **Domain Profile** — Full technology profile for a domain in JSON or XML
- **Free Lookup** — Lightweight free-tier domain technology lookup
- **Relationships** — Domain relationship graph showing related and reseller sites
- **Technology Lists** — Every domain using a given technology
- **Company to URL** — Resolve a company name to its primary domain
- **Trends** — Adoption trend data for technologies over time
- **Domain Signals** — Keywords, redirects, social profiles, and trust score per domain

## Why Jentic

- **Setup:** Wiring BuiltWith by hand means learning its KEY query-parameter auth against api.builtwith.com and picking the right versioned path for lookups, lists, trends, and trust yourself. Through Jentic you install once, import BuiltWith from the API Directory, store the key once, and your agent calls it.
- **Permission scoping:** BuiltWith takes the target domain as a query parameter rather than a URL path segment, so scope the agent by the operations it needs, such as looking up a domain's tech stack or reading trends. Because you choose the allowed operations, it can run domain profiles without being able to pull technology lists unless you add that.
- **Credential handling:** Your BuiltWith API key is stored once, encrypted, by your own Jentic One instance and appended as the KEY query parameter at execution time. It never enters the agent's prompt, logs, or context.
- **Discovery method:** Agents search Jentic by intent such as 'look up a domain tech stack' or 'list domains using a technology', and Jentic returns the matching BuiltWith operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **BulkSMS API** — BulkSMS sends outbound SMS campaigns to leads enriched with BuiltWith tech-stack data.
- **BulkGate API** — BulkGate is an alternative SMS gateway for outbound to BuiltWith-enriched leads.
- **Buildkite API** — Unrelated CI/CD tool - listed as a name-match neighbour, not a substantive integration.

## FAQ

### Which OpenAPI specification does this BuiltWith Domain API page describe?

A curated, agent-optimized Jentic specification covering 11 BuiltWith Domain API operations, validated against the live API and kept up to date. BuiltWith does publish an official OpenAPI 3.1.0 document at https://api.builtwith.com/mppx/openapi.json, but it describes the separate BuiltWith Agent Stripe Credit Top-Up API and its three mppx endpoints, not the domain lookup endpoints on this page. The Jentic variant covers the domain profile, technology list, company-to-URL, trends, social, redirect, and trust operations with agent-ready input schemas. Get started with Jentic One, the self-hosted execution layer.

### What authentication does the BuiltWith Domain API use?

BuiltWith uses an API key passed as the KEY query parameter, or alternatively as Authorization: API {key} in the header. Through Jentic, the key is stored encrypted in the vault and attached to each request at execution time, never exposed to the agent.

### Can I list every domain that uses a specific technology?

Yes. GET `/lists8/api.json` takes a technology name and returns the set of domains BuiltWith has detected running it. Use it to seed account lists for outbound or to size the addressable market for a category.

### Can the BuiltWith API resolve a company name to a website?

Yes. GET `/ctu2/api.json` takes a company name and returns the most likely primary website plus any matched aliases. Pair it with `/v22/api.json` to immediately enrich the resolved domain with its tech stack.

### What are the rate limits for the BuiltWith Domain API?

BuiltWith rate-limits per plan tier and per endpoint, with stricter limits on the free lookup. The OpenAPI spec does not encode the exact quotas - add retry-with-backoff for HTTP 429 responses and prefer the paid `/v22/api.json` for production volume.

### How do I look up a tech stack from an AI agent through Jentic?

Run pip install jentic and authenticate with your ak_* key. Search Jentic with tech stack lookup, load the GET `/v22/api.json` operation, and execute it with the LOOKUP query parameter set to the target domain. Jentic injects the BuiltWith API key automatically.

### Can I limit what my agent is allowed to do with the BuiltWith Domain API?

Yes. Jentic One runs self-hosted, so your own rules decide which BuiltWith operations and credentials the agent may use. Because BuiltWith takes the target domain as a query parameter, you scope the agent by the operations it needs, such as letting it fetch a domain's full technology profile with GET `/v22/api.json` while withholding the technology-list lookup at GET `/lists8/api.json.` You can also allow the company-to-URL and trust-score endpoints selectively, and your BuiltWith key is only attached to the calls you have permitted.