Free Link in Bio PHP Script — Linktree Alternative

BioZip is a link-in-bio page (think Linktree) that you own outright: one PHP file on your domain, no subscription, no branding you didn't choose. Edit your name, emoji avatar, bio, links and theme from a built-in admin editor; every link click is counted, and counts survive edits.

Four color themes ship built in (paper, midnight, ocean, sunset). The avatar is an emoji by design — no image uploads means one less thing to secure. Perfect as the index.php of a links.yoursite.com subdomain.

1. Upload biozip.php to your web space (works great as index.php on a subdomain like links.yoursite.com).
2. Open it in your browser once — it bootstraps with a sample profile.
3. Open biozip.php?a=admin, generate your admin password hash with the built-in generator, paste it into the CONFIG block, then edit your name, emoji, bio, theme and links.

Paste this prompt into Claude to build this exact product:

Build a complete, production-quality single-file PHP application called BioZip: a self-hosted link-in-bio page (a Linktree alternative I own).

Core flow: the file's root URL renders my public bio page — emoji avatar, name, short bio, and a stack of link buttons. Every link click goes through a ?go=LINKID redirect that increments that link's click counter before forwarding.

Hard requirements:

- One PHP file, PHP 8.1+, no database: the whole profile (name, emoji, bio, theme, links with click counts) lives in one JSON file with flock-guarded writes. First run bootstraps a sample profile so the page is never blank.

- CONFIG constants: DEMO_MODE, ADMIN_PASSWORD_HASH, APP_NAME.

- Themes: four built-in color themes (paper, midnight, ocean, sunset) defined as PHP constants and applied via CSS custom properties; derive secondary tones with CSS color-mix so each theme only needs 4 base colors.

- Admin editor at ?a=admin: session login (password_hash, sleep(1) on failure), KPIs (link count, total clicks, active theme), a form editing name / emoji / bio / theme plus a repeatable link-row editor (title + URL per row, add-row button in vanilla JS, empty rows dropped on save). Click counts must survive edits — key links by a stable id and carry counters over on save. Cap at 30 links. CSRF everywhere, first-run hash generator.

- Validation: link targets restricted to http/https/mailto. Length caps on every field.

- Demo mode: public page renders, editing and admin login disabled with a friendly message + banner.

- Avatar is an emoji, not an image upload (security by design — say so in the README). Clean dependency-free CSS.

Also write a README.md: requirements, 3-step install (including the links.yoursite.com subdomain pattern), feature list, security design, honest limits (single profile per install, totals not time-series).

What happened when we ran it: Claude (claude-fable-5) produced the complete file in one pass. Syntax check and the functional tests passed on the first attempt. Your result will differ slightly on every run — that's normal; the spec above pins the behavior, not the exact code.

Note: the download on this page ships with DEMO_MODE = false — no demo restrictions. The prompt is for reproducing (or remixing) the build yourself with your own Claude subscription.