#1: server-side regex highlighter (highlight.go) for go/python/js/json/bash/sql; token span classes styled in app.css; per-line so gutter stays aligned. #2: in-memory token-bucket rate limiter (ratelimit.go) on POST /api/pastes, /api/guess-language and unlock POST; 429 + Retry-After + X-RateLimit headers. #26: new-page JS POSTs the password to /{id} with ?next= after creation; the unlock handler honors same-origin ?next= redirect so the creator lands on the unlocked paste. POST /{id} route added. Tests: ratelimit_test.go (burst/429, refill, unlock limit, highlight, auto- unlock e2e); existing tests updated for per-test limiter isolation.