Font Display Swap
Font Display Swap governs FOUT prevention, shaping system behavior under specific failure modes and workloads.
Definition
Font Display Swap is a design property concerning FOUT prevention. It defines how the system behaves under specific conditions — what guarantees hold, what trade-offs apply, and how the mechanism interacts with related techniques. The property is only meaningful when its preconditions are met; outside those conditions it provides no benefit and may add cost.
Context and scope
Apply Font Display Swap when designing systems where FOUT prevention matters. It is most useful under partial failure, high load, or correctness requirements. Pair it with observability to verify the claimed behavior in production. Do not assume the property holds without testing the specific configuration and workload.
Common misconceptions
- Font Display Swap eliminates all problems in its domain — it only bounds or shapes specific failure modes, not all pathologies.
- Font Display Swap is free once you adopt the right tool — the property depends on configuration, workload, and failure pattern, not the product label alone.
Anti-patterns
- Enabling Font Display Swap without measuring its cost in latency, availability, or operational complexity under production-like conditions.
- Assuming Font Display Swap composes safely with other guarantees — combining mechanisms can introduce new failure modes or negate benefits.
Related concepts
Authoritative source
What it is
Font Display Swap is a design property concerning FOUT prevention. It defines how the system behaves under specific conditions — what guarantees hold, what trade-offs apply, and how the mechanism interacts with related techniques. The property is only meaningful when its preconditions are met; outside those conditions it provides no benefit and may add cost.
When to use
Apply Font Display Swap when designing systems where FOUT prevention matters. It is most useful under partial failure, high load, or correctness requirements. Pair it with observability to verify the claimed behavior in production. Do not assume the property holds without testing the specific configuration and workload.
Common misconceptions
- Font Display Swap eliminates all problems in its domain — it only bounds or shapes specific failure modes, not all pathologies.
- Font Display Swap is free once you adopt the right tool — the property depends on configuration, workload, and failure pattern, not the product label alone.
Anti-patterns to avoid
- Enabling Font Display Swap without measuring its cost in latency, availability, or operational complexity under production-like conditions.
- Assuming Font Display Swap composes safely with other guarantees — combining mechanisms can introduce new failure modes or negate benefits.
Related concepts
- FOIT, FOUT, and Font Loading (font-loading-fout)
- Preload Hints (preload-hints)