ENGINEERING DOCUMENTATION

Patterns before patches.

Use these guides to make implementation choices consistent across products without turning documentation into a copy of private production infrastructure.

API contracts Reliability Accessibility Localization Release gates

Validation & contracts

Validate at boundaries, reject unknown states, keep errors structured and localizable.

Retries & backoff

Retry only idempotent operations, use bounded exponential backoff and record the final failure reason.

Notifications

Event → policy → audience → delivery → receipt. Deep links must resolve inside the intended product.

Localization

Treat language, direction and content translation as separate concerns. UI must remain complete in RTL and LTR.

Privacy

Minimize collection, document purpose and retention, and keep support logs separate from product content.

Release gates

Tests, migrations, security headers, rollback path and observable health checks before production changes.

Reference algorithm: notification delivery

Public-safe pseudocode for a consistent event pipeline.

event = validate(input)
policy = resolve_policy(event.type, user.settings)
if not policy.allowed: stop("policy_blocked")
audience = resolve_audience(event)
for recipient in audience:
  route = choose_channel(recipient, event.priority)
  enqueue(idempotency_key(event, recipient), route)
audit("notification_enqueued")

Engineering rule

Inputs are untrusted until validated at the boundary.

Business policy is explicit, versioned and testable.

Delivery is idempotent; retries cannot duplicate user-visible events.

Audit logs record decisions, not secrets or unnecessary content.