Get started with builders.ac

Choose how you want to use builders.ac: connect your AI assistant or build your own integration with the APIs.

For AI assistant usersUse with AIConnect a compatible AI assistant, such as ChatGPT or Claude, to use builders.ac from your conversations.Connect your AI assistantFor developersBuild with APIsConnect your app to builders.ac to send and read mail, check email delivery, or set up inboxes.Explore API guides

Send and read mail

Point an unmodified Microsoft Graph SDK at our base URL. Your client, your code, your error handling — you change two values and nothing else.

Mailbox APIv1beta1Beta

Base URL

https://api.builders.ac/api/mailbox/v1beta1

API Key

age1…The shared builders.ac API Key. Send it as a bearer token.

Guide · Reference · Graph-compatible routes + event feed

Inspect deliverability

Read traffic, bounce, ESP distribution, and 28-day domain-check analytics for resources owned by your account.

Deliverability APIv1alpha1Alpha / unstable

Base URL

https://api.builders.ac/api/deliverability/v1alpha1

API Key

age1…The same credential used by Mailbox v1beta1 and Provisioning.

Guide · Reference · 6 data operations

Provision inboxes

Internal testing only

The Provisioning API is not supported yet. It is available for internal testing only and must not be used for production workflows.

Create workspaces, connect domains you own, and have real Microsoft 365 inboxes provisioned for them. Authenticate with an API Key and keep the matching API Secret local to open sealed values and destructive-action challenges.

Provisioning APIv1alpha1Internal testing only

Base URL

https://api.builders.ac/api/provisioning/v1alpha1

API Key

age1…The same credential used by Mailbox v1beta1 and Deliverability.

Guide · Reference · 44 operations in 8 groups

Connect with MCP

Connect a compatible AI client to the builders.ac Provisioning MCP server at https://mcp.builders.ac/mcp. Use OAuth or a Provisioning API Key to manage workspaces, domains, personas, inboxes, and operations. Encrypted inbox and domain responses require API-key authentication.

MCP guide

Create an API credential

The Mailbox, Deliverability, and Provisioning APIs share one builders.ac age1… credential.

Authentication explains the shared API Key and Secret, and how to migrate a retiring Mailbox v1alpha1 sk_live_… key.

For agents

The whole site is available as plain text, and all three OpenAPI documents are served directly.

/llms.txt	index
/llms-full.txt	everything, including the complete reference
/llms-small.txt	prose only, for small context windows
/specs/mailbox.json	Mailbox API, OpenAPI 3.1
/specs/deliverability.json	Deliverability API, OpenAPI 3.1
/specs/provisioning.json	Provisioning API, OpenAPI 3.2.0