Logo fallbacks
Monogram generators, deterministic placeholders, retina bundles, refresh caveats, and retry behaviour.
Monogram fallback
When no authoritative logo resolves, LogoRouter optionally returns SVG initials keyed off your apex domain naming rules (fallback=monogram matches the default OpenAPI enumeration).
Prefer 404 or placeholder behaviours when instrumentation must differentiate “no artefact yet” versus “successful synthetic artefact”; both surface distinct response codes / headers upstream of your UI loaders.
Partner with /api/colors/{domain} so chips and cards colourise even without raster assets cached — palette JSON + CDN bytes intentionally stay orthogonal.
OpenAPI enums vs older prose
Historical blog copy sometimes referenced textual aliases — treat openapi.json enum members (monogram, 404, placeholder) as canonical when wiring SDK constants.
Retina sprites
Combine size + retina=true so Workers emit sharper artwork for Hi-DPI breakpoints without rewriting layout contracts downstream.
Refresh & entitlement errors
Even if refresh=true succeeds syntactically, plan entitlements may reject destructive invalidations; expect structured problem bodies outlining available upgrade paths (403-class responses).
Instrument dashboards with both Stripe plan states (How billing works) and x-lr-* headers emitted from the Worker.
Hard upstream failures
DNS / TLS breakage propagates via application/problem+json payloads — guard JSON parsers versus silent HTML tolerant fetchers inside automation.
Retry playbook
On 429 obey Retry-After verbatim when present — otherwise capped exponential backoff (start ~250 ms floor, jitter ~±30 %, exponential cap in low tens of seconds). Never hammer shared demo pools when the response already signals plan upgrade hints.
See also Logo endpoint.