ST-2026-244 · Transition & enforcement
Cloudflare prepares Miniflare v5 with breaking configuration changes
Cloudflare announced a forthcoming Miniflare v5 release that aligns configuration with cloudflare.config.ts and removes or relocates several v4-era APIs, discovery, routing and persistence behaviours.
Previous state
Miniflare v4-era direct consumers could use the prior configuration model, deprecated or internal APIs, built-in module discovery, per-resource persistence and the prior local-routes location.
Current state
The announced v5 line aligns configuration with cloudflare.config.ts, removes deprecated and internal APIs and built-in module discovery, moves local routes and uses a shared persistence root.
Affected users
Who needs to care
Developers and tool maintainers that use Miniflare directly or depend on the affected v4-era configuration, API, module-discovery, routing or persistence behaviours; Cloudflare states most Wrangler, Vite and Vitest users need no action.
Required response
What to do
Direct Miniflare consumers should audit the documented breaking changes and update integrations when adopting v5; users of higher-level Cloudflare tools should follow those tools' release guidance.
Evidence boundary
What the source does not prove
Cloudflare proves the dated announcement and listed intended v5 changes. It does not prove that the future cf CLI or Miniflare v5 is generally available at observation, require most Wrangler/Vite/Vitest projects to act, or establish an unstated release date.
Lifecycle history
Dated event sequence
- Miniflare v5 transition announced
Cloudflare documented the forthcoming v5 configuration, API, module-discovery, routing and persistence changes.
Evidence ledger
First-party sources
- 01Cloudflare — Cloudflare Workers changelog — Miniflare v5 migration
Official Cloudflare Workers lifecycle and migration authority · 2026-09-08
Open official source ↗