The bond system

The idea

A core package is an interface plus an accessor — never a concrete implementation. A bond package is a swappable provider that implements it. Your app’s bonds.ts wires which provider is live — that is configuration, not coupling:

// interface — what the app codes against
import { bond } from '@molecule/api-bond'
// provider — one swappable implementation
import { mailgun } from '@molecule/api-emails-mailgun'

bond('emails', mailgun)

Application code asks the category for the interface and never learns which vendor is behind it. Categories with several live providers (like ai) use named bonds — bond('ai', 'anthropic', ai) — so they coexist.

Swapping providers

Because every provider implements the same interface, swapping is mechanical — one command rewrites the wiring, migrations included where needed:

npx mlcl swap @molecule/api-database-mysql      # Postgres → MySQL
npx mlcl swap @molecule/api-emails-smtp         # Mailgun → plain SMTP

Nothing else in the app changes: same handlers, same calls, different vendor. This is the property the whole ecosystem is built on — decoupling first. Stripe → another processor, one OAuth provider for another, one AI host for another: all one-line moves.

Common categories

The authoritative list for any category is the catalog: npx mlcl search <category> or the packages pages.

Why it matters

• No vendor lock-in — the provider a demo shipped with is not the provider production must keep.
• Per-requirement selection — pick MySQL because the project needs MySQL; nothing in the code changes shape.
• Self-hosting is first-class — many categories have an open-source provider alongside the paid vendors.