Durable Objects

in-progress

Durable Objects (DOs) give Workers stateful, single-instance coordination — counters, rate limiters, websocket rooms, transactional storage. NextDeploy declares classes and migrations.

Source reference: cli/internal/serverless/cloudflare_do.go, shared/nextcompile/ (DO export wiring)

What a Durable Object is

TODO singleton-ish actor — exactly one instance per ID, globally consistent storage, can hold WebSockets. Mental model — a tiny per-key server.

When to reach for one

TODO rate limit per user, real-time room state, leader election, transactional counter — anywhere "one writer at a time" matters.

Status today

TODO Tier A blocker — NextCompile does not yet re-export DO classes from your worker entry. Workaround patterns until lands.

Declaring DO classes

TODO YAML shape — list of class names, the binding name, which migration tag they live in.

Migrations

TODO every change to DO class set is a migration (new_classes, renamed_classes, deleted_classes). NextDeploy tracks them.

Storage API

TODO transactional KV inside the DO — state.storage.get/put/transaction(). Memory limits.

WebSockets

TODO DOs can hibernate and resume — the right place for long-lived sockets.

Custom in/out methods

TODO RPC vs fetch — current Workers convention.

Pricing

TODO request count + duration + storage + transactions, free tier.