AbortController timeout

Signal passed to fetch

Retry on 5xx

Exponential backoff

Response cloned before read

CORS preflight handled

CORS headers on responses

Content-type check before JSON parse

Timeout cleanup

Error documented in output

Parallel requests used

Streaming without buffer

Cache check first

ctx.waitUntil for cache.put

response.clone() before cache.put

Cache-Control header set

tee() for dual consumers

pipeThrough for transforms

Reader lock released

Cache miss handling

TextEncoder for encoding

HMAC SHA-256 algorithm

importKey with 'raw' format

Crypto in try/catch

URL-safe Base64 for signatures

btoa pattern for ArrayBuffer

SHA-256 hex digest

Verify uses subtle.verify

Key never extractable

Invalid key error handled

TextDecoder for output