Reference & Lookup Data · Integration
CallerAPI
Add CallerAPI to your product for your customers, and give your AI agents governed access to it.
CallerAPI is a phone intelligence service that returns business identity, spam scoring and carrier data for a number in a single lookup. Authentication is an API key sent in an x-auth header rather than the usual Authorization bearer scheme, which trips up most HTTP clients configured from a generic template. The service is geo-steered: api.callerapi.com routes automatically, while callerapi.com serves EU and us-east.callerapi.com serves US East, so pinning a region matters if you care about where lookup traffic lands. Billing is credit-based rather than seat-based, and /api/me returns credits_left, credits_monthly and credits_spent, so a sensible integration reads that endpoint before a bulk enrichment run instead of discovering exhaustion mid-batch. Coverage is uneven by country, so treat a missing name as absent data rather than a negative result. fastn holds each customer's own key, handles the regional base URL, and keeps the connection working as credit plans and endpoints change.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let a customer connect their own CallerAPI account so inbound numbers in your product are resolved to a business name at call time.
Score inbound leads against the spam database before they are routed to a sales queue.
Enrich a stored contact list with carrier and line-type data so SMS sends skip landlines.
Show a caller identity panel in your softphone UI drawn from the customer's own lookup credits.
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
Let an agent look up an unknown number that appeared in a call log and report the identity and spam score, with each lookup audited per tenant against that tenant's own credit balance.
Have an agent batch-check a list of numbers before an outbound campaign and flag ones with a high spam score.
Let an agent report remaining monthly credits and warn when a planned enrichment run would exceed them.
Example prompt
Who is calling from +44 20 7946 0958, and is that number flagged as spam?
Set up CallerAPI in 4 steps
- 01Enable the CallerAPI connector from your fastn dashboard.
- 02Have each customer authorise their own CallerAPI 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 CallerAPI integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a CallerAPI integration without building it. Your customers connect their own CallerAPI 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 CallerAPI update is not your on-call problem.
- One integration serves your product and your agents. The same governed CallerAPI 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
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SnowflakeCallerAPI integration FAQ
How do I add a CallerAPI integration to my product?
Enable the CallerAPI connector in your fastn dashboard, then let each customer authenticate their own CallerAPI account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no CallerAPI client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own CallerAPI account?
Yes. Every connection is scoped to the individual customer, so each authorises their own CallerAPI 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 CallerAPI 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 an unknown number that appeared in a call log and report the identity and spam score, with each lookup audited per tenant against that tenant's own credit balance.
Who maintains the CallerAPI integration?
fastn does. When CallerAPI 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 CallerAPI 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 CallerAPI results be cached?
Per tenant, with a window that matches how fast the underlying data actually moves. CallerAPI 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 CallerAPI integration?
A common starting point: let a customer connect their own CallerAPI account so inbound numbers in your product are resolved to a business name at call time. 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 CallerAPI integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding CallerAPI does not change your per-connector cost. You can start free with 3 connected accounts.
Add CallerAPI to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.