#ADR 0001: workers-rs on Cloudflare, axum as the router, runtime-agnostic core

Status: accepted, 2026-09-05

#Context

Ventures need a stateless backend with near-zero ops. Compute must be able to move to self-hosted infrastructure later without touching modules.

v1 runtime is Cloudflare Workers via workers-rs (worker crate, http and d1 features), built with worker-build, deployed with wrangler.
The router is axum (default-features = false). workers-rs can serve an axum Router directly, and the same Router runs on tokio natively.
cratefield-core depends on http, axum, serde, tracing and pure-Rust crypto only. No worker, wasm-bindgen, tokio, std::fs or std::net in core or in modules. Runtime crates own those.

A dependency that only works natively (tokio runtime, mio, native TLS) cannot enter core or a module; CI's worker-build step catches it.
cratefield-runtime-native is a thin crate: axum on tokio plus native adapters.

Mirrored from docs/adr/0001-workers-rs-and-axum.md at b6f50cd. The harness is the source of truth: a correction goes there first.