Open Source Licenses
Attribution for the open source software we build on.
Postlyo incorporates third-party open source software. This Notice acknowledges those components and satisfies the attribution requirements of their licences.
The Postlyo platform itself is proprietary and is not open source. See our Copyright & IP Notice.
1. Why this page exists
Most permissive open source licences — MIT, BSD, Apache 2.0, ISC — require that the copyright notice and licence text be reproduced in distributions of the software or in its documentation. Publishing this page is how that requirement is met for a hosted web application.
2. Licence composition
| Licence | Prevalence | Obligations |
|---|---|---|
| MIT | The large majority | Reproduce copyright notice and licence text |
| Apache-2.0 | Several components | Reproduce notice, licence, and any NOTICE file; state significant changes |
| ISC | A small number | Reproduce copyright notice and licence text |
| BSD-2-Clause / BSD-3-Clause | A small number | Reproduce copyright notice, licence, and disclaimer |
None of these require us to release our own source code. They are compatible with a proprietary hosted product, provided attribution is given.
3. Principal components
Frontend — Next.js and React (MIT); Tailwind CSS (MIT); Radix UI primitives (MIT); Tiptap editor components (MIT); Zod (MIT); Zustand (MIT); React Hook Form (MIT); date-fns (MIT); Lucide icons (ISC); Sonner (MIT); clsx and tailwind-merge (MIT).
Backend — Fastify and its official plugins (MIT); Drizzle ORM (Apache-2.0); the postgres client; ioredis (MIT); Zod (MIT); sanitize-html (MIT); sharp (Apache-2.0); bcrypt (MIT); the AWS SDK for JavaScript S3 client (Apache-2.0); the Google APIs Node.js client (Apache-2.0); the Razorpay Node SDK (MIT); p-limit (MIT); dotenv (BSD-2-Clause).
Tooling — TypeScript (Apache-2.0); ESLint (MIT); Prettier (MIT); Vitest (MIT); Wrangler and the OpenNext Cloudflare adapter (MIT/Apache-2.0).
This list is illustrative, not exhaustive. The complete list, including transitive dependencies and full licence texts, is available on request.
4. Full licence texts
The complete list of components, versions, copyright holders and verbatim licence texts is available from legal@postlyo.com.
To be completed by the website owner — generate the full attribution file and publish it at a stable URL, then link it here. Run a license checker over the production dependency tree, review for any copyleft licence (GPL, LGPL, AGPL, MPL, SSPL), and reproduce the contents of any Apache-2.0 NOTICE file. Automate it in CI so the published file cannot drift from what is deployed.
5. Fonts and assets
To be completed by the website owner — record the licence and any attribution requirement for typefaces, icon sets, illustrations and stock imagery used in the product and on the marketing site.
6. Reporting an attribution problem
If you believe your open source component is used without proper attribution, or in breach of its licence, contact legal@postlyo.com with the component name and the licence term concerned. We will investigate and correct promptly.
7. Disclaimer
Open source components are provided by their authors under their respective licences, typically without warranty. Postlyo makes no representation about them beyond what those licences state.
This document is provided in English. If we publish a translation and there is a conflict, the English version governs unless local law requires otherwise.