# Product analytics

OSGKeyboard analytics records product behavior metadata only. It is separate
from billing, provider execution and immutable credit ledgers.

## Privacy boundary

Never send or persist:

- audio or audio-derived content;
- keyboard input, prompts, context, transcripts or model output;
- Apple subjects, email addresses, names, tokens, API keys or provider
  credentials;
- arbitrary property names or free-form text.

The service stores a SHA-256 digest of the random installation identifier, not
the identifier supplied by the client. Event DTO string representations are
redacted. Product analytics rows linked to an account are deleted with that
account. Anonymous installations that never link to an account are retained for
90 days and are eligible for scheduled deletion in a later operational job.

## Ingestion API

`POST /v1/analytics/events` accepts one batch of 1 to 50 events.

- Authentication is optional so first-open and pre-login events can be
  measured. Invalid bearer credentials are rejected.
- `installationId` must be a client-generated UUID stored in the containing app
  and shared with the keyboard extension through the App Group.
- When a valid account session is present, the installation is linked to that
  account. An installation cannot later be linked to a different account.
- Every `clientEventId` is a client-generated UUID. The pair
  `(installation, clientEventId)` is unique.
- Replaying an identical event is accepted and reported as replayed.
- Reusing an event ID with different values returns `409 conflict`.
- The whole batch is validated before persistence and committed atomically.
- `occurredAt` must be no more than 35 days old and no more than five minutes in
  the future. UTC ISO-8601 timestamps are required.

The successful response reports `accepted` and `replayed` event counts. It does
not return account or installation identifiers.

## Event catalog

### Lifecycle events

`FIRST_OPEN`

- Required: `surface=APP`, `acquisitionChannel`.
- Optional: `appVersion`, `osVersion`.
- Must be emitted once per installation. Server idempotency protects retries.

`SESSION_STARTED`

- Required: `surface` (`APP` or `KEYBOARD`).
- Optional: `appVersion`, `osVersion`.

`KEYBOARD_ACTIVATED`

- Required: `surface=KEYBOARD`.
- Emit when the custom keyboard becomes active, not for every keystroke.

### AI events

`AI_FEATURE_STARTED`

- Required: `feature`, `executionMode`, `surface`.
- Optional: `durationBucket` is not allowed.

`AI_FEATURE_SUCCEEDED`

- Required: `feature`, `executionMode`, `surface`, `durationBucket`.
- This is the client-side core value event.
- Managed totals remain server-authoritative; the event provides feature and
  surface detail.

`AI_FEATURE_FAILED`

- Required: `feature`, `executionMode`, `surface`, `failureCategory`.
- Optional: `durationBucket`.
- Never include provider response bodies or user content.

### Purchase events

`PURCHASE_VIEWED`

- Required: `surface=APP`.

`PURCHASE_STARTED`

- Required: `surface=APP`.

`PURCHASE_CANCELLED`

- Required: `surface=APP`, `failureCategory=CANCELLED`.

Successful purchases are derived from verified StoreKit transactions and must
not be duplicated as client success events.

### Referral events

`REFERRAL_SHARED`

- Required: `surface=APP`.

`INVITE_OPENED`

- Required: `surface=INVITE_WEB`, `acquisitionChannel=REFERRAL`.
- The app may emit this event after handling an invitation Universal Link.
- The first-party web route separately increments a UTC daily aggregate after
  validating the referral code. It stores no IP address, user agent, cookie,
  installation ID, referral code, or other request metadata.
- No third-party analytics script is permitted.

Referral binding, value qualification and reward are derived from server data.

## Allowed dimensions

`surface`

- `APP`
- `KEYBOARD`
- `INVITE_WEB`

`acquisitionChannel`

- `APP_STORE_ORGANIC`
- `REFERRAL`
- `SOCIAL_CONTENT`
- `UNKNOWN`

`feature`

- `TRANSCRIPTION`
- `POLISH`
- `AI_ASSISTANT`
- `AGENT`
- `HOTWORD`
- `OTHER`

`executionMode`

- `MANAGED`
- `LOCAL`
- `BYOK`

`failureCategory`

- `NETWORK`
- `PROVIDER`
- `TIMEOUT`
- `CANCELLED`
- `INSUFFICIENT_CREDITS`
- `VALIDATION`
- `UNKNOWN`

`durationBucket`

- `LT_1S`
- `S1_TO_3`
- `S3_TO_10`
- `S10_TO_30`
- `GTE_30S`

`appVersion` and `osVersion` are optional ASCII release identifiers of at most
32 characters. They may not contain spaces, user-generated values or device
names.

## Client delivery guidance

- Persist pending events in an append-only local queue.
- Retry with exponential backoff after network failures and HTTP 5xx.
- Drop events rejected with HTTP 400/422 after recording a local diagnostic
  counter; do not retry malformed events indefinitely.
- Reuse the same `clientEventId` for every retry.
- Send at most 50 events per batch and remove events only after a successful
  response.
- Do not block the AI interaction or purchase flow on analytics delivery.

## Reporting

The admin analytics endpoints combine:

- accepted product events for acquisition, local/BYOK usage and client funnel
  detail;
- settled credit usage for managed AI counts and credit consumption;
- accounts, StoreKit and referrals for registration, monetization and referral
  outcomes.

Metric formulas are defined in
[`ANALYTICS_METRICS_DICTIONARY.md`](ANALYTICS_METRICS_DICTIONARY.md).