Filament v4 Custom Field Plugin: Signature Pad | Mohamed Said [Skip to content](#main) [ ![](https://cdn.msaied.com/01KT78WE565VEMM3PSNQAAB0MH.png) Mohamed SaidLaravel Backend Engineer ](https://msaied.com) - [Home](https://msaied.com) - [Projects](https://msaied.com/projects) - [Articles](https://msaied.com/articles) - [Certificates](https://msaied.com/certificates) - [About](https://msaied.com#about) [ Contact](https://msaied.com#contact) Menu Menu ---- Close - [HomeStart here](https://msaied.com) - [ProjectsCase studies](https://msaied.com/projects) - [ArticlesEngineering notes](https://msaied.com/articles) - [CertificatesCredentials](https://msaied.com/certificates) - [AboutHow I work](https://msaied.com#about) - [ContactGet in touch](https://msaied.com#contact) [Start a conversation](https://msaied.com#contact) [WhatsApp](https://wa.me/201094619204) [Email](mailto:hello@msaied.com) 1. [Home](https://msaied.com) 2. / 3. [Articles](https://msaied.com/articles) 4. / 5. Filament v4 Custom Field Plugins: Building a Reusable Signature Pad Component Filament v4 Custom Field Plugins: Building a Reusable Signature Pad Component ============================================================================== Learn how to build a production-ready Filament v4 custom field plugin — a signature pad — covering asset registration, schema integration, state hydration, and Livewire interop. ![](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp) [Mohamed Said](https://msaied.com#person) Published 5 Jul 2026 · Updated 5 Jul 2026 · 3 min read ShareCopy linkCopied ![Filament v4 Custom Field Plugins: Building a Reusable Signature Pad Component](https://cdn.msaied.com/369/4654a4b25d88862c21064130ec028ffb.png) On this page +1. [Building a Reusable Signature Pad Field for Filament v4](#building-a-reusable-signature-pad-field-for-filament-v4) 2. [Project Structure](#project-structure) 3. [Registering Assets the Right Way](#registering-assets-the-right-way) 4. [The Field Class](#the-field-class) 5. [The Blade View and Alpine Wiring](#the-blade-view-and-alpine-wiring) 6. [The Alpine Component](#the-alpine-component) 7. [Consuming the Field](#consuming-the-field) 8. [Storing the Payload](#storing-the-payload) 9. [Key Takeaways](#key-takeaways) Building a Reusable Signature Pad Field for Filament v4 ------------------------------------------------------- Filament v4's unified Schema API makes custom field plugins more composable than ever. Rather than fighting the framework with raw Blade hacks, you can ship a self-contained package that drops cleanly into any `Form`, `Infolist`, or `Table` schema. This walkthrough builds a real signature pad field — the kind you'd use in a contracts or onboarding flow — and covers every layer from asset bundling to state hydration. ### Project Structure ```php src/ SignaturePad.php # Field class SignaturePadServiceProvider.php resources/ js/signaturePad.js # Alpine component views/ signature-pad.blade.php ``` ### Registering Assets the Right Way Filament v4 uses `FilamentAsset` for scoped asset loading — assets are only injected when the component is actually rendered, not globally. ```php // SignaturePadServiceProvider.php use Filament\Support\Assets\AlpineComponent; use Filament\Support\Facades\FilamentAsset; public function boot(): void { FilamentAsset::register([ AlpineComponent::make('signature-pad', __DIR__ . '/../dist/signature-pad.js'), ], package: 'acme/filament-signature-pad'); $this->loadViewsFrom(__DIR__ . '/../resources/views', 'signature-pad'); } ``` Using `AlpineComponent` instead of a raw `Js` asset tells Filament to lazy-load and register the Alpine component automatically — no manual `Alpine.data()` call in your app. ### The Field Class ```php // SignaturePad.php namespace Acme\FilamentSignaturePad; use Filament\Forms\Components\Field; class SignaturePad extends Field { protected string $view = 'signature-pad::signature-pad'; protected bool $clearable = true; protected string $format = 'image/png'; public function clearable(bool $condition = true): static { $this->clearable = $condition; return $this; } public function format(string $mimeType): static { $this->format = $mimeType; return $this; } public function getClearable(): bool { return $this->clearable; } public function getFormat(): string { return $this->format; } } ``` Keep the field class thin. Business logic (e.g., converting the base64 payload to a stored file) belongs in a dedicated action or cast, not here. ### The Blade View and Alpine Wiring ```blade {{-- resources/views/signature-pad.blade.php --}} Clear ``` The `ax-load` / `ax-load-src` pattern is Filament v4's lazy Alpine loader. It fetches the component script only when the DOM node is present. ### The Alpine Component ```javascript // resources/js/signaturePad.js export default function signaturePad({ state, clearable, format }) { return { state, clearable, drawing: false, init() { const canvas = this.$refs.canvas; const ctx = canvas.getContext('2d'); canvas.addEventListener('mousedown', () => { this.drawing = true; ctx.beginPath(); }); canvas.addEventListener('mousemove', (e) => { if (!this.drawing) return; const r = canvas.getBoundingClientRect(); ctx.lineTo(e.clientX - r.left, e.clientY - r.top); ctx.stroke(); }); canvas.addEventListener('mouseup', () => { this.drawing = false; this.state = canvas.toDataURL(format); }); }, clear() { const canvas = this.$refs.canvas; canvas.getContext('2d').clearRect(0, 0, canvas.width, canvas.height); this.state = null; } }; } ``` State is synced back to Livewire via `$entangle` on `mouseup` — not on every `mousemove` — keeping wire calls minimal. ### Consuming the Field ```php use Acme\FilamentSignaturePad\SignaturePad; SignaturePad::make('signature') ->clearable() ->format('image/svg+xml') ->required() ->columnSpanFull(), ``` ### Storing the Payload The field stores a raw base64 data URL. Convert it on save using a model observer or a dedicated action: ```php // In your CreateRecord action or observer $data['signature'] = (new StoreSignatureImage)($data['signature']); ``` Keep the conversion outside the field — the field's only job is capturing and surfacing state. ### Key Takeaways - Use `FilamentAsset::register` with `AlpineComponent` for scoped, lazy asset loading. - `ax-load` / `ax-load-src` defers Alpine component hydration until the DOM node exists. - `$entangle` + `$applyStateBindingModifiers` is the canonical way to sync custom field state with Livewire. - Keep field classes thin; push persistence logic to actions or observers. - Publish views via `loadViewsFrom` so consumers can override templates without forking the package. - [filament](https://msaied.com/articles?search=filament) - [laravel](https://msaied.com/articles?search=laravel) - [livewire](https://msaied.com/articles?search=livewire) - [plugins](https://msaied.com/articles?search=plugins) Frequently asked questions --------------------------- How do I handle touch events for mobile signature capture?Add `touchstart`, `touchmove`, and `touchend` listeners in your Alpine component alongside the mouse events. Extract the coordinates with `event.touches\[0\].clientX` and call `preventDefault()` on touchmove to stop page scrolling during drawing. Can I validate the signature field to ensure it isn't empty?Yes. Because the field stores a string (the data URL) or null, you can chain `->required()` on the field. For a more precise check — ensuring the canvas isn't just a blank white rectangle — add a custom Filament validation rule that inspects the data URL length or pixel entropy. How do I make the component work inside a Filament Infolist for read-only display?Create a companion `SignaturePadEntry` class extending `Filament\\Infolists\\Components\\Entry` with its own Blade view that renders an `<img>` tag from the stored data URL. The field and entry are separate classes in Filament v4's unified Schema API. ![Mohamed Said](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp)About the author ---------------- [Mohamed Said](https://msaied.com#person)Senior Backend Engineer specializing in Laravel, scalable SaaS platforms, APIs, and cloud infrastructure. I build secure, high-performance web applications that help businesses grow. [About](https://msaied.com#about) [GitHub ↗](https://github.com/EG-Mohamed) [LinkedIn ↗](https://www.linkedin.com/in/msaiedm/) [WhatsApp ↗](https://wa.me/201094619204) [Email Address ↗](mailto:hello@msaied.com) [My CV ↗](https://drive.google.com/file/u/0/d/1MF20IPRJyzfy32mhEutjL5EpSls0w2Q8/view) [Previous articleAdvanced Authorization in Laravel: Gates, Policies, and Response-Based Access Control](https://msaied.com/articles/advanced-authorization-in-laravel-gates-policies-and-response-based-access-control-2) [Next articleOctane Worker Lifecycle, State Leakage, and Safe Singleton Patterns in Laravel](https://msaied.com/articles/octane-worker-lifecycle-state-leakage-and-safe-singleton-patterns-in-laravel) On this page ------------- 1. [Building a Reusable Signature Pad Field for Filament v4](#building-a-reusable-signature-pad-field-for-filament-v4) 2. [Project Structure](#project-structure) 3. [Registering Assets the Right Way](#registering-assets-the-right-way) 4. [The Field Class](#the-field-class) 5. [The Blade View and Alpine Wiring](#the-blade-view-and-alpine-wiring) 6. [The Alpine Component](#the-alpine-component) 7. [Consuming the Field](#consuming-the-field) 8. [Storing the Payload](#storing-the-payload) 9. [Key Takeaways](#key-takeaways) ### Have a technical challenge? Tell me what you’re building. I reply within two working days. [Start a conversation](https://msaied.com#contact) Related articles ----------------- [ ![](https://cdn.msaied.com/739/2d6897fdcdcf090613f96f72a64b8a78.png) · 4 min read### MySQL Full-Text Search in Laravel: Indexes, Relevance Scoring, and Boolean Mode 4 Oct 2026 ](https://msaied.com/articles/mysql-full-text-search-in-laravel-indexes-relevance-scoring-and-boolean-mode) [ ![](https://cdn.msaied.com/738/073696a3fefe18bec825beec5ac658f5.png) · 4 min read### Laravel Queue Rate-Limited Middleware: Throttling Jobs Without Losing Work 4 Oct 2026 ](https://msaied.com/articles/laravel-queue-rate-limited-middleware-throttling-jobs-without-losing-work) [ ![](https://cdn.msaied.com/737/f5c7e78a645325d4cff8d43f2835f136.png) · 4 min read### Laravel Telescope Alternatives: Structured Observability with Pulse, Debugbar, and Custom Watchers 4 Oct 2026 ](https://msaied.com/articles/laravel-telescope-alternatives-structured-observability-with-pulse-debugbar-and-custom-watchers) Have a technical challenge? ---------------------------- Tell me what you’re building. I reply within two working days. [Discuss your project ↗](https://msaied.com#contact) © 2026 Mohamed Said · Built with Laravel, meant to last.Senior Backend Engineer specializing in Laravel, scalable SaaS platforms, APIs, and cloud infrastructure. I build secure, high-performance web applications that help businesses grow. - [Home](https://msaied.com) - [Articles](https://msaied.com/articles) - [Certificates](https://msaied.com/certificates) - [GitHub](https://github.com/EG-Mohamed) - [LinkedIn](https://www.linkedin.com/in/msaiedm/) - [WhatsApp](https://wa.me/201094619204) - [Email Address](mailto:hello@msaied.com) - [My CV](https://drive.google.com/file/u/0/d/1MF20IPRJyzfy32mhEutjL5EpSls0w2Q8/view) - [Sitemap](https://msaied.com/sitemap.xml)