One route, two adapters (dev vs. production)

adapter-fs and adapter-sqlite aren't really alternatives to pick once and live with — they map cleanly onto two different moments of the same project's life:

• npm run dev (local, solo) — @instafix/adapter-fs. No database, no server process, plain files under .instafix/ at your project root. This is also the only adapter meant to run this way — its constructor throws under NODE_ENV === "production" on purpose (see the filesystem adapter).
• npm run start / deployed (team, durable) — @instafix/adapter-sqlite. A real embedded database (WAL mode, real transactions, indexed search/pagination) that a small team can point a shared dashboard at, still with nothing external to provision.

Since both are already createInstaFixHandler({ store }) behind the same shared-handler contract (auth, CORS, validation, webhooks — see the SQLite adapter), one route.ts can pick between them at runtime instead of committing to one:

// app/api/instafix/route.ts
import { createInstaFixHandler, SqliteStore } from "@instafix/adapter-sqlite";
import { FsStore } from "@instafix/adapter-fs";

const store =
  process.env.NODE_ENV === "production"
    ? new SqliteStore({ path: "./instafix.db" })
    : new FsStore();

export const { GET, POST, PATCH, DELETE, OPTIONS } = createInstaFixHandler({ store });

Install both packages:

npm install @instafix/adapter-fs @instafix/adapter-sqlite

Why this split, specifically

• adapter-fs's .instafix/history.jsonl is plain text a coding agent can read directly with no query tooling — exactly the point while you're mid-session with an agent locally. It's also refused outright in production, so this pairing can't accidentally ship the dev path to real traffic.
• adapter-sqlite needs a persistent disk under the same process across requests — true of a normal npm run start on a VPS/container, not true of stateless serverless functions (Vercel Functions, Lambda). If you deploy there, use @instafix/adapter-prisma against a real managed database instead; this dev/prod split assumes a traditional always-on host.
• Nothing about the widget or the dashboard changes — both adapters implement the same InstaFixStore contract, so <InstaFixWidget />/<InstaFixInbox /> don't know or care which one is live underneath.

instafix init's part in this

init still asks once and wires up a single backend — it doesn't generate the conditional snippet above. If you want this dev/prod split, run init, pick SQLite, then hand-edit the generated route.ts to match the snippet above (and add the @instafix/adapter-fs install it skipped).