Error Handling

import { Aside } from ‘@astrojs/starlight/components’;

The SDK never throws into your app and never blocks your render. But placements and entitlement checks degrade in opposite directions, on purpose: a placement that can’t resolve renders nothing, while an entitlement check that can’t resolve denies.

Two degradation modes

Placements are additive. If RevTurbine is paused, misconfigured, or unreachable, a slot renders nothing (or your configured fallback) — it can never take your product down.

Entitlement checks are fail-closed. If a check can’t produce an affirmative grant, it returns { status: 'denied', allowed: false } rather than granting access. The Playbook is cached and persisted locally, so a configured runtime evaluates real allow/deny answers with no network round-trip; the failure fallback only fires when the SDK has no basis to answer at all — no config, no cache, nothing reachable — which is exactly where denying is the safe, non-leaking default. The reason code is preserved so you can still tell an outage apart from a real denial.

API failure scenario	SDK behavior
API unreachable	Placements return visible: false
Entitlement check fails	Returns { status: 'denied', allowed: false, reason: 'config_unavailable' }
Config fetch fails	Falls back to cached Playbook; with none, entitlement checks deny
Event delivery fails	Events are buffered and retried silently

Error Surface

Hook Level

Hooks expose errors as strings — they never throw:

const { error, isLoading } = usePlacement({ placement: { name: 'hero_banner' } });
const { error: entError } = useEntitlement({ handle: 'data_export' });

if (error) {
  // Non-critical — log and continue
  console.warn('Placement error:', error);
}

Controller Level

Headless controllers surface errors through state:

const ctrl = new PlacementController(sdk, config);
await ctrl.load();

if (ctrl.state.error) {
  console.warn('Controller error:', ctrl.state.error);
}

SDK Level

Most SDK methods fail silently and return sensible defaults:

// Returns allowed on API failure
await sdk.can('data_export');

// Silently drops event on delivery failure
await sdk.track('page_viewed');

// Returns null decision on failure
await sdk.getPlacement({ slotId: 'banner' });

Provider Failure Behavior

When the provider chain is exhausted (all providers failed), slots behave according to providerFailureSlotBehavior:

<RevTurbineProvider
  options={{
    ...options,
    providerFailureSlotBehavior: 'invisible', // default
  }}
>
  <YourApp />
</RevTurbineProvider>

Value	Behavior
'invisible'	Slots render nothing — your layout stays intact
'placeholder'	Slots render fallback placeholder content

Recommendation

Use 'invisible' (default) for production. Placements are additive — your app should work fine without them.

Use 'placeholder' during development to visually verify that slots are wired correctly even when the provider is down.

Reason Codes

Placement decisions include reason_codes that explain why a placement was hidden or shown:

Code	Meaning
cap_limit_exceeded	Impression cap reached
suppressed	User recently dismissed/snoozed
plan_mismatch	User’s plan doesn’t match targeting
segment_mismatch	User doesn’t match targeting segment
config_not_loaded	Playbook not yet available
api_error	API returned non-200
network_error	Network/timeout failure
fallback_content	Using fallback placeholder

Inspecting Reason Codes

const { decision } = usePlacement({ placement: { name: 'hero_banner' } });

if (decision?.reason_codes?.includes('cap_limit_exceeded')) {
  // User has seen this placement too many times
}

Entitlement Reason Codes

Entitlement checks are fail-closed. When the SDK cannot produce an affirmative grant — the Playbook never arrived, no rule grants the entitlement to the user’s plan, the SDK was disabled — it returns { status: 'denied', allowed: false } with a reason naming the cause. It never defaults to allowed. Treat allowed as the answer and reason as the explanation; the codes below are the complete set the SDK emits.

Denied because a rule said so

Reason	Meaning
no_matching_entitlement_rule	No rule grants this entitlement to the user’s plan. Plan targeting is explicit — an entitlement with no enabling rule for that plan is not granted.
feature_not_enabled_for_plan	A matching feature rule has enabled: false.
usage_limit_reached	The user is at or over a usage_limit rule’s limit.
credit_balance_exhausted	The user is at or over a credits rule’s allowance.

usage_limit_reached and credit_balance_exhausted carry a suffix reflecting the rule’s enforcement mode:

Suffix	enforcement	Outcome
(none)	hard_block	denied — hard stop
(none)	unset	limited, not allowed
_block_with_upsell	block_with_upsell	denied — render the upsell placement
_degraded	degrade	limited but allowed (throttled, not blocked)
_overage	allow_overage	allowed — metered overage

Two modes produce no suffix and they are not equivalent: hard_block denies, while leaving enforcement unset returns limited and does not allow. Branch on allowed, never on the presence of a suffix.

Renamed in schema v15

block_with_upsell was previously called soft_block. The name was misleading — soft_ reads as permissive, but the mode denies; it just tells you to render an upsell rather than a hard stop. Behaviour is unchanged, and the old spelling is still accepted when it appears in an already-compiled Playbook, so existing payloads keep deciding exactly as before. The reason code it produces is now ..._block_with_upsell in every case.

Denied because the SDK could not decide

Reason	Meaning
config_unavailable	The launched Playbook could not be fetched (Server mode). Not a rule decision — an infrastructure failure.
entitlement_not_in_playbook	Local mode with no Playbook and no cached result: nothing describes this entitlement, so there is no basis to grant it.
sdk_disabled_provider_failure	The SDK disabled itself after a provider failure.

Allowed with a reason

Reason	Meaning
granted_by_reverse_trial	Granted by an active reverse trial rather than by the user’s plan.

Renamed in 0.3.0

local_runtime_default_allow is now entitlement_not_in_playbook. The old name stated a verdict the result does not have — it denies — and was also emitted by the headless runtime on an allowed result, so one code meant opposite things on two surfaces. There is no deprecated alias; update any switch on the old string.

Two entitlement types are not gates

price_per_unit and rate_limit entitlements always evaluate to allowed. This is by design and is the one explicit carve-out from the fail-closed rule: they are non-gating metadata, present to populate text tokens (an overage price in upgrade copy, a documented rate ceiling), not to control access. Do not gate a feature on one of them — a price_per_unit check answering “allowed” tells you the price exists, not that the user may proceed.

Retry Behavior

Operation	Retry Strategy
Placement resolution	No auto-retry. Call refresh() to retry manually.
Entitlement check	No auto-retry. Call recheck() to retry manually.
Event delivery	Auto-buffered and retried on next batch interval.
Config fetch	Falls back to cached config. Retried on next SDK initialization.

Manual Retry

const { refresh, error } = usePlacement({ placement: { name: 'hero_banner' } });
const { recheck, error: entError } = useEntitlement({ handle: 'data_export' });

// Retry after transient failure
if (error) await refresh();
if (entError) await recheck();

Graceful Degradation Pattern

Structure your components so the SDK enhancement is purely additive:

function Dashboard() {
  return (
    <div>
      {/* Baseline UX — always works */}
      <DashboardContent />

      {/* SDK enhancement — fails gracefully to nothing */}
      <Slot id="dashboard_banner" />
    </div>
  );
}

If the SDK is down, <Slot> renders nothing and the baseline dashboard continues working.

Debugging Errors

Enable verbose logging to diagnose issues:

// In browser console
localStorage.setItem('revturbine:debug', 'true');

This logs decision resolution, provider chain evaluation, and error details to the browser console.

Next Steps

• Configuration Reference — error-related configuration options
• Error Codes Reference — enumerated error codes