Filament Language Switcher Laravel Package

Product Decisions This Supports

• Build vs. buy — buy, and treat it as infrastructure, not a feature. A language switcher is a bounded surface: configurable topbar dropdown, translated locale names, optional flags, per-user persistence, and app.locale fallback. That is roughly a week of undifferentiated work plus ongoing edge-case maintenance. Scope it as an enabler for any multi-locale admin experience and spend product effort on work only your team can differentiate.
• Security posture — v5 is a risk-closure decision, not a feature decision. v5.0.0 restricts the switch route to the signed-in user’s language, returns 403 to guests, rejects unconfigured locales, and ignores model / model_id query parameters. Pre-v5 behavior instantiated any class named in the request and allowed one user to change another user’s language. Any pre-v5 deployment should be logged as a security finding with an owner and a remediation date.
• Version pinning as a product guardrail. Adopt with an explicit ^5.0 constraint, not a floating range. The important change in this package is a security change; a routine composer update should not decide when you cross that line.
• Roadmap coupling — sequence it as a rider, not a standalone initiative. v5 hard-requires Filament v5, Livewire 4, Laravel 12/13, and PHP 8.2+. Adopting v5 means the Filament 5 migration is already funded or is being forced by this choice. If the team is intentionally staying on Filament v4 for a quarter or more, this package no longer tracks that path by default.
• Open risk to resolve before sign-off. Release notes say the Filament v4 code is preserved on the 4.x branch; they do not confirm the v5 security fix was backported. Until that is confirmed in writing, “we’ll just stay on 4.x” is not an acceptable answer for a user-facing admin surface.
• Adoption signal, read honestly. 37 stars, zero dependents, MIT, effectively single-maintainer — thin external validation. The counterweight is real: v5 ships a new test suite with coverage, screenshots, an install command that runs migrations in-process, an app.locale fallback, and a fix for rendering when the current locale is not configured. That reads as active hardening, not abandonment — but budget for the possibility of forking.
• Use cases this unblocks: multi-language internal admin tooling; per-user (explicitly not per-tenant) locale preference; localization QA where a reviewer flips languages on their own account; support and demo scenarios where a non-technical operator can switch languages safely; customer-facing panels only by deliberate decision, because that turns an internal preference into a customer-visible toggle.

When to Consider This Package

Adopt when:

• Your admin surface is Filament and you already run — or are funded to move to — Filament v5 / Livewire 4 / Laravel 12+ on PHP 8.2+.
• Locale is a per-user preference. v5’s security model enforces exactly that, so the fix aligns with intended design rather than fighting it.
• You need a switcher in days, not a localization subsystem in weeks.
• You want the locale list in config with translated display names, optional flags, and a safe fallback to app.locale for users who never chose.
• You can keep the integration thin: one topbar dropdown, one user column, one config file, and a small middleware to apply the stored locale per request.
• You are willing to own the four security assertions in CI: guests get 403, model / model_id are ignored, unconfigured locales are rejected, and a victim user’s language cannot be changed by another user.

Look elsewhere or build alongside when:

• You need tenant-level locale, session locale, geo/Accept-Language negotiation, or content translation. This package switches a stored user preference; it is not a localization platform.
• You are staying on Filament v4 and cannot get written confirmation that the v5 security fix was backported to 4.x. Treat every pre-v5 deployment as an open security finding, not a default.
• You need a large, well-supported dependency with broad community validation. This is a small, single-maintainer package; keep it forkable and avoid building tenant/session negotiation on top of it.
• Your locale column is not the default users.language assumption, or your user model lives on a non-standard table. That is the most likely reason you will need to read the source or override; confirm it in a test immediately after install.
• You need the switcher on a customer-facing panel without a deliberate product decision. Adding the plugin per panel is easy; turning a per-user preference into a customer-visible toggle should be intentional.

How to Pitch It (Stakeholders)

For executives — the one-paragraph version. This is a small, MIT-licensed Filament plugin that adds a per-user language switcher to the admin panel. The v5 release closes a real security gap: previously, a crafted request could change another user’s language or instantiate an arbitrary class; now the route only updates the signed-in user, rejects guests, rejects unconfigured locales, and ignores user-supplied model parameters. The cost is low and the scope is bounded, but it is coupled to the Filament 5 / Livewire 4 / Laravel 12 upgrade. Recommendation: adopt ^5.0 as a rider on that upgrade, pin the major explicitly, and resolve in writing whether the v4 branch received the security backport before any pre-v5 deployment remains in production.

For engineering — the operating summary. Register the plugin per panel, keep the locale allowlist in config/filament-language-switcher.php, and treat config labels as user-facing copy. Publish and read the migration before the install command runs in a pipeline; in v5 it runs migrations in-process, which is convenient locally but should be an observable deploy step in CI. Add middleware after auth to apply user->language with an allowlist guard and fall back to app.locale; do not backfill nulls unless you want to freeze today’s default. Mirror the four security cases in tests, plus UI cases for missing current locale, show_flags on/off, untranslated locale names, and null user locale. Under Octane or long-lived workers, set and reset locale at request/job boundaries. Keep the integration thin so forking remains cheap.

Decision ask. Approve adoption of tomatophp/filament-language-switcher:^5.0 after the Filament 5 upgrade lands, assign an owner to confirm the 4.x backport status in writing, and budget a small contingency for taking ownership of a 37-star, single-maintainer package. Do not frame this as a localization platform; frame it as a safe, cheap topbar preference backed by one column and one config file.