How do we cache NHS patient data compliantly with Redis?

NHS patient data Redis caching: (1) never cache raw NHS patient records (full FHIR Patient resources with NHS number) in Redis without encryption — use AWS KMS encryption for ElastiCache at rest, (2) short TTL (15–30 minutes for active consultation data — patient demographics rarely change, but too long is GDPR risk), (3) invalidation on update (FHIR patient resource updated → Redis DEL patient:nhsNumber — immediate invalidation), (4) no persistent storage of personal data in Redis (Redis AOF/snapshots disabled for patient data cache — or encrypted snapshots to S3 with lifecycle policy), (5) NHS DTAC Domain 2: ElastiCache encryption at rest (AWS-managed key) documented in DPIA. ClickMasters NHS Redis configuration: KMS encryption, 15-minute TTL for patient data, immediate DEL on FHIR update webhook.

Should UK FinTech use Redis for FCA PS21/3 rate limiting?

Redis atomic operations (INCR, EXPIRE) are the standard for FCA-regulated API rate limiting: (1) Redis INCR per-customer-per-minute counter (atomic — no race condition), (2) EXPIRE sets counter TTL (60 seconds — counter resets after 1 minute), (3) if counter > limit → 429 response (FCA PS21/3: rate limiting must not block legitimate IBS access — limit must be set above typical usage patterns), (4) CloudWatch metric (Redis cache hit rate + rate limit trigger events — IBS availability evidence). FCA PS21/3 caveat: rate limiting that blocks legitimate customer access to IBS is itself a PS21/3 availability failure — ClickMasters sets rate limits at 10× expected peak usage (generous — protects against DDoS, does not affect legitimate customers).

Redis Vs Memcached Vs Dynamodb Dax Uk 2026

Redis vs Memcached vs DynamoDB DAX — UK Application Caching (2026)

Updated: March 20269 min read

🇬🇧 UK💷 GBP📊 Comparison🔒 UK GDPR⚖️ UK Law

Direct Answer

Redis (AWS ElastiCache for Redis) is the UK default for application caching: richer data structures (sorted sets for leaderboards, pub/sub for real-time), persistence (can survive restart), and the broadest UK ecosystem (TanStack Query uses Redis for session, NHS patient data caching, FCA rate limiting). Memcached is right for simple key-value caching where Redis features are overkill and cost matters at scale. DynamoDB DAX is right exclusively when DynamoDB is your primary database and you need microsecond read latency. Caching strategy affects UK GDPR personal data handling, NHS DTAC audit trail requirements, and FCA PS21/3 IBS availability.

Factor	Redis (ElastiCache)	Memcached (ElastiCache)	DynamoDB DAX
UK GDPR personal data caching	✅ TTL per key — precise NHS patient data expiry	TTL available — less fine-grained	In-memory — same TTL controls as DynamoDB
NHS patient data cache invalidation	✅ DEL key on FHIR resource update — immediate invalidation	✅ DELETE available	DynamoDB write invalidates DAX automatically
FCA rate limiting (PS21/3)	✅ Redis atomic operations — rate limiting without race conditions	Not suitable for atomic rate limiting	Not designed for rate limiting
Session management	✅ Standard — connect-redis, next-iron-session	Simple session cache	DynamoDB-specific
Pub/Sub (real-time notifications)	✅ Native pub/sub — real-time clinical alerts	Not available	Not available
Data persistence (survive restart)	✅ RDB snapshots + AOF — survives restart	No persistence — data lost on restart	DynamoDB persistent
Cost at medium scale	Medium	✅ Cheaper than Redis at same cache.t3.small	DynamoDB pricing + DAX pricing
ClickMasters default	✅ All NHS/FCA/retail UK caching	Simple non-critical caching	DynamoDB-only architectures