Deadsimple Email Usage API

openapi: 3.2.0
info:
  title: Dead Simple Email Usage API
  version: 0.1.0
  description: 'Email API for AI agents. Create inboxes, send and receive email,

    manage threads, and get real-time webhook notifications.


    ## Authentication

    All authenticated endpoints use Bearer token auth:

    ```

    Authorization: Bearer dse_your_api_key

    ```


    ## Agent self-signup

    Autonomous agents can provision an account, a key, and a live inbox in one

    unauthenticated call — no human, no verification email:

    ```

    POST /v1/auth/agent-signup

    ```

    That returns a `trial` account (1 inbox, 10 sends/hour, 25 sends/day) with a

    scoped key. `POST /v1/auth/claim` attaches a verified email and moves it to

    the Free plan, keeping the same key, inboxes and history.


    ## Sign in with Dead Simple (OpenID Connect)

    `https://id.deadsimple.email` is an OpenID Connect provider where the

    identity is an agent''s inbox: `sub` is the `inbox_id`, `email` is the inbox

    address. Discovery at `/.well-known/openid-configuration`, JWKS at

    `/.well-known/jwks.json`, ES256 id_tokens, authorization-code + PKCE S256,

    RFC 7591 registration at `/register`. Open clients (client_id = the app''s

    https origin) need no registration. An agent authenticates at `/authorize`

    with `Authorization: Bearer dse_...` plus `inbox_id=`, or with an ES256

    assertion signed by a key enrolled via `/v1/inboxes/{inbox_id}/identity/keys`;

    the one-call helper `POST /v1/inboxes/{inbox_id}/identity/sign-in` wraps

    this for SDKs and the MCP server. Endpoints on the `id.deadsimple.email`

    host are tagged **Identity Provider** below and carry their own `servers`

    entry.


    ## Pay per request (no API key)

    Twelve priced routes can be called with no credentials at all. They answer

    `402 Payment Required` carrying an x402 v2 `PAYMENT-REQUIRED` header (USDC

    on Base, Polygon or Solana, `exact` scheme, PayAI facilitator; the same

    JSON is repeated in the body for v1 clients) and, on `POST /v1/inboxes`,

    a `WWW-Authenticate: Payment` challenge for Stripe''s Machine Payments

    Protocol. Retry with `PAYMENT-SIGNATURE` (x402 v2), `X-PAYMENT` (v1) or

    `Authorization: Payment ` (MPP). x402 payments are verified

    before the work and settled after it; MPP charges first and refunds if

    the work fails. Prices: inbox $1.00, send/reply/reply-all/forward $0.01,

    reads $0.005. The paying wallet keys a `payg` account, and the first paid

    inbox returns `credentials` (an API key) in the response so later reads

    and sends within the plan are free. See the reusable `402` response and

    https://deadsimple.email/pay-per-request.html.


    ## Idempotency

    POST endpoints accept an `Idempotency-Key` header. Same key within 24h

    returns the cached response without re-executing.


    ## Rate Limits

    Every response includes rate limit headers:

    - `X-RateLimit-Limit` — requests per window

    - `X-RateLimit-Remaining` — remaining requests

    - `X-RateLimit-Reset` — window reset timestamp


    On `429`, a `Retry-After` header gives the seconds to wait. Per-account

    limits scale with plan (`rate_limit_rpm`); public/unauthenticated endpoints

    are additionally limited per IP.


    ## Webhook Reliability

    Every event is a durable delivery: the first attempt runs immediately and

    failures are retried on an exponential-backoff schedule (configurable per

    webhook via `/v1/webhooks/{id}/config`; default `[1, 30, 300, 1800, 7200,

    86400]` seconds). Deliveries are HMAC-SHA256 signed on **all plans**. The

    per-webhook delivery log (`/v1/webhooks/{id}/deliveries`) records every

    attempt with status and error, and any delivery can be replayed. Endpoints

    that fail repeatedly are auto-disabled.


    ## WebSocket Streaming

    Connect to `wss://ws.deadsimple.email?api_key=dse_...` for real-time events.


    After connecting, subscribe to specific inboxes/events:

    ```json

    {"action": "subscribe", "inbox_ids": ["..."], "events": ["message.received"]}

    ```


    Events are pushed as JSON with the same payload as webhooks. Send `{"action": "ping"}`

    to keep the connection alive (10-minute idle timeout).'
  contact:
    url: https://deadsimple.email
  license:
    name: MIT
servers:
- url: https://api.deadsimple.email
  description: Production
security:
- BearerAuth: []
tags:
- name: Usage
paths:
  /v1/usage:
    get:
      summary: Get usage metrics
      tags:
      - Usage
      parameters:
      - $ref: '#/components/parameters/WorkspaceHeader'
      responses:
        '200':
          description: Current billing period usage stats
      operationId: getV1Usage
      x-operation-id-source: derived
  /v1/metrics:
    get:
      summary: Metrics time series
      description: 'Activity bucketed into fixed UTC intervals: messages sent and received, bounces, complaints, first opens and first clicks of tracked sends, webhook deliveries and terminal failures, and inbound messages the prompt-injection scanner flagged (medium or high). Derived live from the account''s rows; outcomes are attributed to messages created inside the window, and opens/clicks count once per message. Requires `usage.read`. Honours workspace scoping and inbox-scoped API keys.'
      tags:
      - Usage
      parameters:
      - $ref: '#/components/parameters/WorkspaceHeader'
      - name: from
        in: query
        required: false
        schema:
          type: string
        description: 'Start of the window, inclusive. ISO date (`2026-09-01`) or datetime (`2026-09-01T12:00:00Z`; naive means UTC). Default: 30 days before `to`.

          '
      - name: to
        in: query
        required: false
        schema:
          type: string
        description: 'End of the window, exclusive. A date-only value means the end of that day, so `from=2026-09-01&to=2026-09-07` is seven whole days. Default: now. The window may span at most 92 days.

          '
      - name: interval
        in: query
        required: false
        schema:
          type: string
          enum:
          - day
          - hour
          default: day
        description: Bucket size. `hour` is allowed only for windows of 7 days or less.
      - name: inbox_id
        in: query
        required: false
        schema:
          type: string
        description: 'Comma-separated inbox ids (max 100) to restrict the series to. Each must belong to the account and be visible to the key; otherwise 404.

          '
      responses:
        '200':
          description: Bucketed series plus totals over the whole window
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Metrics'
              example:
                interval: day
                from: '2026-09-01T00:00:00Z'
                to: '2026-09-03T00:00:00Z'
                series:
                - start: '2026-09-01T00:00:00Z'
                  sent: 42
                  received: 17
                  bounced: 1
                  complained: 0
                  opened: 12
                  clicked: 4
                  webhook_deliveries: 59
                  webhook_failures: 0
                  injection_flagged: 2
                - start: '2026-09-02T00:00:00Z'
                  sent: 38
                  received: 21
                  bounced: 0
                  complained: 0
                  opened: 9
                  clicked: 3
                  webhook_deliveries: 59
                  webhook_failures: 1
                  injection_flagged: 0
                totals:
                  sent: 80
                  received: 38
                  bounced: 1
                  complained: 0
                  opened: 21
                  clicked: 7
                  webhook_deliveries: 118
                  webhook_failures: 1
                  injection_flagged: 2
        '400':
          description: Bad window (from after to, over 92 days, hour over 7 days, unparseable date) or interval
        '404':
          description: An inbox in `inbox_id` is not visible to this key
      operationId: getV1Metrics
      x-operation-id-source: derived
  /v1/deliverability:
    get:
      summary: Deliverability report
      description: Aggregated delivery outcomes for outbound mail over a time window — delivery, bounce, and complaint rates for the whole account/workspace, broken down per inbox and per sending domain, plus a hard/soft bounce breakdown and suppressed-address count. See exactly what's landing without dedicated IPs or infra to manage.
      tags:
      - Usage
      parameters:
      - $ref: '#/components/parameters/WorkspaceHeader'
      - name: days
        in: query
        schema:
          type: integer
          default: 30
        description: Lookback window in days (1–90).
      - name: inbox_id
        in: query
        schema:
          type: string
        description: Restrict the report to a single inbox.
      - name: domain
        in: query
        schema:
          type: string
        description: Restrict the report to a single sending domain.
      responses:
        '200':
          description: Deliverability aggregates for the window.
          content:
            application/json:
              schema:
                type: object
                properties:
                  period:
                    type: object
                    properties:
                      days:
                        type: integer
                      since:
                        type: string
                        format: date-time
                      until:
                        type: string
                        format: date-time
                  totals:
                    type: object
                    description: Status counts plus total, delivery_rate, bounce_rate, complaint_rate.
                  bounce_breakdown:
                    type: object
                    properties:
                      hard:
                        type: integer
                      soft:
                        type: integer
                      by_subtype:
                        type: object
                        additionalProperties:
                          type: integer
                  by_inbox:
                    type: array
                    items:
                      type: object
                  by_domain:
                    type: array
                    items:
                      type: object
                  suppressed_addresses:
                    type: integer
      operationId: getV1Deliverability
      x-operation-id-source: derived
components:
  schemas:
    Metrics:
      type: object
      properties:
        interval:
          type: string
          enum:
          - day
          - hour
        from:
          type: string
          format: date-time
        to:
          type: string
          format: date-time
        series:
          type: array
          items:
            $ref: '#/components/schemas/MetricsBucket'
        totals:
          $ref: '#/components/schemas/MetricsBucket'
    MetricsBucket:
      type: object
      properties:
        start:
          type: string
          format: date-time
          description: Bucket start, UTC.
        sent:
          type: integer
        received:
          type: integer
        bounced:
          type: integer
        complained:
          type: integer
        opened:
          type: integer
          description: Messages opened for the first time in this bucket (tracked sends only).
        clicked:
          type: integer
          description: Messages whose first link click fell in this bucket (tracked sends only).
        webhook_deliveries:
          type: integer
          description: Webhook deliveries that reached the endpoint.
        webhook_failures:
          type: integer
          description: Deliveries that exhausted their retry budget.
        injection_flagged:
          type: integer
          description: Inbound messages rated medium or high by the prompt-injection scanner.
  parameters:
    WorkspaceHeader:
      name: X-Workspace-Id
      in: header
      required: false
      schema:
        type: string
        format: uuid
      description: Target a specific workspace. Required for account-wide API keys that want workspace-scoped results.
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: API key (dse_...), session token (JWT), or OAuth 2.1 access token (dse_oat_..., obtained via the authorization-code + PKCE flow below)
    OAuth2:
      type: oauth2
      description: OAuth 2.1 for MCP clients. Public clients only (PKCE S256 required, no client secret). Supports RFC 7591 dynamic client registration at /oauth/register and discovery via /.well-known/oauth-authorization-server. Access tokens carry inbox/message permissions only (no billing, team, or API-key administration).
      flows:
        authorizationCode:
          authorizationUrl: https://api.deadsimple.email/oauth/authorize
          tokenUrl: https://api.deadsimple.email/oauth/token
          refreshUrl: https://api.deadsimple.email/oauth/token
          scopes:
            email: Send, receive, and manage email inboxes
    OpenIDConnect:
      type: openIdConnect
      openIdConnectUrl: https://id.deadsimple.email/.well-known/openid-configuration
      description: 'Sign in with Dead Simple. Relying parties use this to authenticate an agent by its inbox; it is not used to call the Dead Simple API itself. Scopes: openid, email, profile (open clients); owner_email, org, offline_access (registered clients only).'