Reference & Lookup Data · Integration
BuiltWith
Add BuiltWith to your product for your customers, and give your AI agents governed access to it.
BuiltWith answers technology-profile lookups at api.builtwith.com, currently on the v21 domain API, and it carries two habits that break naive clients. First, the key travels as a KEY query string parameter rather than a header, so it ends up in access logs, proxy traces and browser history unless requests are made server-side and scrubbed. Second, an invalid key does not produce a 401: the service returns HTTP 200 with a body of {"Errors":[{"Message":"API Key is incorrect","Code":-2}]}, so status-code-based error handling will silently treat a broken credential as a successful empty result and every retry still burns quota. Beyond the domain lookup there are separate products for lists, which resolve a technology to the domains using it, plus relationship and trends endpoints, and each is metered differently, so a single key does not mean access to all of them. Results carry first-detected and last-detected dates rather than a live reading, meaning a technology can persist in a profile after it has actually been removed and freshness has to be judged from those dates. fastn keeps each customer's BuiltWith key server-side, normalises the 200-with-errors response into a real failure and maintains the connection over time.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let a customer connect their own BuiltWith key so lookups run against their quota and their entitlements
Enrich inbound leads with the technologies detected on their domain at the point of signup
Build a target list from a technology and score it against the customer's own fit criteria
Show first-detected and last-detected dates in your UI so sales know how stale a signal is
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
Let an agent look up one domain's stack on request and report the detection dates alongside the answer
Have an agent enrich a batch of accounts within a quota cap, with each lookup audited per tenant
Let an agent flag accounts whose detected stack changed since the last enrichment run
Example prompt
What analytics and payment tools is this prospect's website running, and how recently were they detected?
Set up BuiltWith in 4 steps
- 01Enable the BuiltWith connector from your fastn dashboard.
- 02Have each customer authorise their own BuiltWith account, so calls run under their credentials rather than a shared key.
- 03Decide which lookups, results and reports your product needs, map those fields, then enable the actions and triggers you want.
- 04Call it from your product and expose it to your agents through the same governed connection.
Why teams use the BuiltWith integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a BuiltWith integration without building it. Your customers connect their own BuiltWith account inside your product and work their lookups, results and reports there, with no per-customer code on your side.
- Handle the part that actually costs time: these are metered read sources, so an uncached lookup on every page view burns the customer's allowance. fastn owns the auth, token refresh, rate limits, pagination and breaking-change fixes, so a BuiltWith update is not your on-call problem.
- One integration serves your product and your agents. The same governed BuiltWith connection powers in-product features and gives AI agents scoped, audited access, so you answer questions from an authoritative outside source without holding that data yourself without wiring it twice.
Used by these teams
Compare with
Clearbit
APIVoidOften used alongside
Tools the same teams tend to run next to BuiltWith, across other categories.
Salesforce
HubSpot
Notion
SnowflakeBuiltWith integration FAQ
How do I add a BuiltWith integration to my product?
Enable the BuiltWith connector in your fastn dashboard, then let each customer authenticate their own BuiltWith account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no BuiltWith client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own BuiltWith account?
Yes. Every connection is scoped to the individual customer, so each authorises their own BuiltWith account and only ever sees their own lookups, results and reports. That per-tenant isolation is the point of an embedded integration: you support the long tail of customer setups without maintaining an integration per customer.
Can AI agents use this BuiltWith integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. Let an agent look up one domain's stack on request and report the detection dates alongside the answer
Who maintains the BuiltWith integration?
fastn does. When BuiltWith changes an endpoint, deprecates a field or alters its auth, the fix lands in the connector rather than in your backlog, and your customers' connections keep working.
Whose credentials does a BuiltWith lookup run under?
Each customer's own. Quota and cost land on the customer that caused them rather than on a shared key you have to meter and re-bill, and one heavy customer cannot exhaust another's allowance.
How should BuiltWith results be cached?
Per tenant, with a window that matches how fast the underlying data actually moves. BuiltWith is a read source rather than a system of record, so the same query returns the same answer until the source changes, and caching is the difference between a sustainable integration and one that exhausts a customer's allowance on a busy page.
What can I build with the BuiltWith integration?
A common starting point: let a customer connect their own BuiltWith key so lookups run against their quota and their entitlements. Teams also use it for the other use cases listed above, and expose it to agents for governed reads and writes.
How much does the BuiltWith integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding BuiltWith does not change your per-connector cost. You can start free with 3 connected accounts.
Add BuiltWith to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.