Comparison

BuilderJS vs Mosaico: a modern, supported self-hosted builder

Both are editors you self-host and own — each is the design surface, not the delivery layer: neither one is a sending platform or a hosting service, so you still bring your own ESP for delivery and your own server or CDN for pages. Mosaico is the original open-source email template editor: free under GPL-3.0, battle-tested, and embedded in many ESPs since 2015. If you only need an email-template editor, can live with its Knockout.js / Grunt-based stack, and are comfortable with the GPL (or buying the commercial license to avoid copyleft), Mosaico is a sensible, zero-cost-of-entry choice. BuilderJS is a newer, framework-agnostic vanilla-JS library (~140KB) that mounts in any DOM node across React, Vue, Svelte, Angular, Next.js, Laravel or plain HTML, and builds both Outlook-safe email HTML and web/landing-page HTML from one JSON model. It ships a one-time CodeCanyon license with author support for roughly 6-12 months. Choose Mosaico for free GPL email-only; choose BuilderJS for a modern, supported, dual-output editor you embed in any framework.

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BuilderJS vs Mosaico, side by side

Dimension	BuilderJS	Mosaico
Pricing model	One-time CodeCanyon license (item 27146783): Regular $52 / Extended $99. No SaaS, no monthly fee, no per-seat, no usage metering.	Free editor under GPL-3.0; optional paid commercial/non-GPL license for teams avoiding copyleft, reportedly from ~EUR 800 + VAT one-time per a third-party review, not posted on the vendor's own page (verify with sales) (as of June 2026).
License & source access	Full source delivered; you own and self-host it. Permissive enough to embed in your own app; not copyleft.	Full source on GitHub under GPL-3.0 — strong copyleft, so derivative/distributed work may need to be GPL too unless you buy the commercial license (as of June 2026).
Hosting & data residency	You self-host. Reference PHP backends (MySQL/SQLite/S3) you copy and own; data stays on your infrastructure.	You self-host. The editor is front-end; you supply your own backend for save/upload (the public mosaico.io demo uses a private backend) (as of June 2026).
Email output (Outlook/Gmail-safe)	EmailExportPipeline: flexbox to table, SVG to PNG, @media mobile-stack, MSO conditionals, CSS inliner. 30+ templates / 200+ samples Litmus-tested across 22 clients.	Core strength — produces responsive, client-safe HTML email; mature and widely used in production ESPs since 2015 (as of June 2026).
Page/landing building	Yes — builds both web/landing-page HTML and email HTML from one JSON model. You bring the hosting/publishing.	No — email templates only; not designed to output web/landing pages (as of June 2026).
Framework integration	Framework-agnostic vanilla-JS DOM-mount bundle (~140KB). Mounts in React (useEffect), Vue (onMounted), Angular, Svelte, Next.js (dynamic import ssr:false), Laravel or plain HTML — client-side only.	Knockout.js-based single-page library built with Grunt; usable but not a drop-in for modern component frameworks (as of June 2026).
Extensibility (custom blocks)	Custom Elements/Widgets/Controls via Builder.registerElement; themes; i18n 20+ locales with RTL. Extend without forking. 42 element types, 59 controls, 31 overlays.	Extensible via custom blocks/templates and Knockout bindings, but customization generally means working within its template format and JS conventions (as of June 2026).
Backend (save/upload/auth)	Reference PHP backends for save + upload + auth (MySQL/SQLite/S3) that you copy and own; portable to Node/Go/Python. JSON-first getData()/load() lossless round-trip.	No official production backend bundled; you implement save/upload/auth yourself (sample/Docker setups exist for testing) (as of June 2026).
Support & updates	Time-boxed author support (~6-12 months) plus ongoing source ownership; updates via CodeCanyon.	Community/GitHub support; commercial support available by contacting the vendor. Maintained but on a mature release cadence (latest v0.18.11, late 2024) (as of June 2026).

Mosaico's editor is free and open-source under GPL-3.0; the source is on GitHub (latest release v0.18.11, late 2024) and you self-host it. An optional commercial/non-GPL license is sold for teams that cannot accept copyleft — reportedly from EUR 800 + VAT as a one-time/lifetime license per a third-party review, but this figure is not posted on Mosaico's own commercial page, so confirm by contacting sales on the vendor's page (as of June 2026). BuilderJS is a one-time CodeCanyon purchase (item 27146783): Regular $52 / Extended $99 — you own the source and self-host, with no SaaS, monthly fee, per-seat charge, usage metering, or phone-home. Author support is time-boxed (~6-12 months). Always verify each product's current terms on its own page before buying.

Choose BuilderJS if…

Choose BuilderJS when you need one editor that builds both Outlook-safe email and web/landing pages, must embed cleanly in React, Vue, Angular, Svelte, Next.js or Laravel, want a non-copyleft license you own outright, and value a modern vanilla-JS stack with reference backends and time-boxed author support.

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Choose Mosaico if…

Choose Mosaico when you only need an email-template editor, want a free, proven open-source tool with years of production use across many ESPs, are comfortable with GPL-3.0 (or will buy its commercial license to avoid copyleft), and don't mind its Knockout.js / Grunt-based stack or building your own backend.

Frequently asked questions

Is Mosaico free, and is BuilderJS free too?

Mosaico's editor is free and open-source under GPL-3.0; you self-host it from GitHub (latest release v0.18.11, late 2024). It also offers an optional paid commercial/non-GPL license for teams that cannot accept copyleft, reportedly from EUR 800 + VAT one-time per a third-party review (confirm with the vendor, as of June 2026). BuilderJS is a one-time CodeCanyon purchase (Regular $52 / Extended $99) with no subscription. The comparison isn't 'cheaper than free' — it's a free, GPL, email-only editor versus an owned, framework-agnostic editor that builds both email and pages (verify both vendors' current terms before buying).
Can either tool send my email or host my pages?

No. Both Mosaico and BuilderJS are editors you embed — they produce the template or markup, and you bring your own ESP for delivery and your own server or CDN for hosting. BuilderJS builds both email HTML and web/landing-page HTML; Mosaico builds email templates only. Deliverability, automation, CRM, funnels, and payments all stay in your own stack — neither tool provides them.
Does BuilderJS build web/landing pages, or just email like Mosaico?

BuilderJS builds both. From a single JSON model it can output Outlook-safe email HTML (via its EmailExportPipeline) or standard web/landing-page HTML, so the same editor covers newsletters and pages — you bring the hosting to publish them. Mosaico is purpose-built for responsive email templates only and is not designed to produce web/landing pages.
Why pick BuilderJS over a free GPL tool like Mosaico?

Mosaico is free and proven, but it is email-only, built on Knockout.js with a Grunt build, GPL-3.0 copyleft (which can complicate embedding in proprietary products), and you build your own backend. BuilderJS adds a modern framework-agnostic vanilla-JS mount (~140KB) for React/Vue/Angular/Svelte/Next.js/Laravel, dual email-and-page output, reference save/upload/auth backends you own, a non-copyleft license, and time-boxed author support. It's a finished, supported, framework-agnostic tool — not a question of price against free.
How does each integrate with a React or Vue app?

BuilderJS ships as a DOM-mount bundle (dist/builder.js + dist/builder.css) you mount client-side in useEffect (React) or onMounted (Vue) — in Next.js via dynamic import with ssr:false and 'use client' — then persist with getData() POSTed to your route. Mosaico is a Knockout.js single-page library built with Grunt; it works but isn't a drop-in modern component.

Sources

Competitor facts are dated (as of June 2026) and linked — always verify current figures on each vendor's own site.