AI calling API with an OpenAPI 3.1 spec: build on it today.
A pay-as-you-go REST API for outbound AI phone calls, described in a public OpenAPI 3.1 spec. Bearer keys, full lead and campaign management, transcripts, recordings and reports.
What the FoxEra Calls API covers
The FoxEra Calls REST API lets your own code, automation platform or GPT Action trigger and manage outbound AI phone calls. It covers the full campaign lifecycle:
- Leads — create, update and organise leads into folders.
- Campaigns — preview a campaign (headcount, estimated cost, calling agent), create it, schedule it, approve it, or cancel it.
- Outcomes — read the result of every call: answered, voicemail, no answer, and the prospect's response.
- Transcripts and recordings — pull the full transcript and a link to the call recording for any completed call.
- Reports — campaign-level summaries: total calls, connected minutes, cost, warm leads.
- Account — check credit balance, set calling hours, choose the AI agent (Cass, Alex or Andrea), edit and approve the pitch.
Authentication uses bearer API keys (format fxk_...). Each key is scoped to one workspace and can be revoked instantly from your developer settings.
The OpenAPI 3.1 spec
The full API is described in an OpenAPI 3.1 document at a public URL:
https://app.foxera.co.uk/api/public/openapi.json
You can import this spec into any tool that reads OpenAPI: Postman, Insomnia, Swagger UI, or your own code generator. It is also the format that GPT Actions accepts directly — paste the URL and your custom GPT can call the API without writing any integration code.
The spec documents every endpoint, request body, response shape and error code. If you want to turn the spec into MCP tools for an AI assistant, the MCP vs API key comparison explains when each approach fits.
How to get started
- Create a free FoxEra Calls account at foxera.co.uk. New accounts get £7 of free calling credit.
- Go to your developer settings and generate an API key. The key starts with
fxk_and acts only inside your workspace. - Include the key as a bearer token in the
Authorizationheader of every request. - Start by adding a few leads via the API, then preview a campaign to see the headcount and estimated cost before approving.
The API uses standard REST conventions: JSON request and response bodies, HTTP status codes for errors, and pagination on list endpoints. Full details are in the developer guide.
Safety and approval flow
The API enforces the same safety rules as the dashboard and the MCP server:
- Confirmed headcount — every campaign requires the exact number of leads to be confirmed before approval.
- Separate approval step — creating a campaign does not start calls. You must explicitly approve it in a second request.
- Calling hours — calls are placed only within the hours you configure. Outside those hours, the campaign waits.
- Scoped keys — each API key works inside one workspace only. Revoking a key stops all access immediately.
- Full logging — every API action is logged with a timestamp, so you can audit exactly what happened and when.
These rules are enforced server-side, regardless of what client or model is calling the API. Read more about AI agent guardrails for outbound calls.
Use cases for the API
The API is designed for developers and automation builders who want to integrate outbound calling into their own systems:
- CRM integration — push new leads from your CRM into FoxEra and pull call outcomes back, keeping both systems in sync.
- Automation platforms — trigger a calling campaign from n8n, Make or a Zapier webhook when a new lead arrives in your pipeline.
- GPT Actions — import the OpenAPI spec into a custom GPT so it can manage campaigns conversationally.
- Reporting dashboards — pull campaign data into your own analytics or outbound calling CRM for combined reporting.
- Custom agents — build an autonomous agent that researches prospects, adds them to FoxEra, previews a campaign and asks your approval before dialling.
If you prefer a conversational interface over code, you can connect ChatGPT or any assistant via the MCP server instead.
Pricing
The API itself is free to use. You pay only for calls that connect, from 12p per connected minute, with no subscription and no platform fee. New accounts start with £7 of free calling credit.
Every campaign preview shows the estimated cost before you approve, so there are no surprises. Compare this to monthly-seat models on the pricing page or use the cost calculator to estimate a campaign.
Frequently asked questions
Where is the OpenAPI spec hosted?
The spec is at https://app.foxera.co.uk/api/public/openapi.json. It is public and always up to date. Import it into Postman, Swagger UI, or any tool that reads OpenAPI 3.1.
How much does the API cost to use?
The API is free. You pay only for connected call minutes, from 12p per connected minute. New accounts get £7 of free calling credit.
Can the API start calls without my approval?
No. Creating a campaign does not start calls. You must confirm the headcount and send a separate approval request. This is enforced server-side.
Does the API work with GPT Actions?
Yes. The OpenAPI 3.1 spec can be imported directly into a GPT Action. Your custom GPT can then manage leads, campaigns and results conversationally.