Browser extension that watches the pricing pages of every SaaS you subscribe to and alerts you the moment they change — $5/mo, no enterprise-y setup.

What we ship

**Core features (MVP)**

• Chrome extension (Plasmo): a "Watch this page" button on any SaaS pricing page — one click adds it to your watchlist.
• Webapp dashboard: list of every tracked vendor with status, last diff, next-check ETA, and a pause/resume toggle.
• Extension-side polling preferred: the user's browser fetches pricing pages (sidesteps server-side ToS exposure); server-side fallback rate-limited to ≤1 req/page/24h.
• Semantic AI explanation: Claude Haiku 4.6 doesn't just HTML-diff — it produces a one-liner like "Notion increased Plus seat from $10 to $12 (+20%); deprecated Personal Pro tier".
• Weekly digest email: every Sunday — all changes across the week, sorted by impact (price-up / price-down / tier-restructure / feature-removed).

**Primary user flow**

1. SMB owner sees their statement, notices an extra $80, googles "saas price increase alert" — lands on the page.

2. Installs the Chrome extension in 30 seconds, opens 5 familiar SaaS pricing pages (notion.so/pricing, linear.app/pricing, slack.com/pricing), clicks "Watch this page" on each.

3. Next morning opens the webapp dashboard — sees 5 rows "no changes yet" + next-check ETA.

4. Eleven days later receives an email "Linear bumped Standard from $8 to $10 per user (+25%) — affected: 4 seats = +$8/mo for you" — upgrades to $5/mo.

**What it looks like**

• **Landing page**: hero "Get charged more, silently. Not anymore." Animated screenshot — Notion pricing page changes from $10 → $12 with a red diff badge, email lands in inbox. Stat-bar: "11.4% YoY hikes (Lemkin/SaaStr 2025)". CTA: "Install free Chrome extension".
• **Main app screen**: webapp dashboard — table of tracked vendors (logo, name, last-checked, status chip "stable" / "changed 3d ago" / "checking..."), "+ Add via extension" button at top. Clicking a row opens a drawer with snapshot timeline and Claude's summary of each change.
• **Output format**: email alert "**Linear** bumped Standard $8 → $10 (+25%). Your impact: 4 seats × $2 = +$8/mo. [view diff] [pause]"; Sunday weekly digest; optional Slack webhook.

**MVP build plan (7 days)**

• Day 1: FastAPI + Postgres + Celery (Redis) on Railway, JWT, Stripe Subscriptions ($5/mo).
• Day 2: Snapshot storage on Cloudflare R2, diff engine (HTML → text → semantic diff).
• Day 3: Claude Haiku 4.6 prompt for "what changed" summary, JSON output, dedup.
• Day 4: Plasmo Chrome extension — "Watch this page" injection + sync with webapp via API token.
• Day 5: React + Tailwind webapp dashboard, list + detail drawer + timeline.
• Day 6: Resend for weekly digest + instant-alert email, Slack webhook delivery.
• Day 7: Landing page, ToS + bot-policy page, Chrome Web Store submission, ship.

Source signals

• **SIG-20260425-us-micro-saas-utility-saas-pricing-change-monitor**: "browser extension that monitors saas subscription pricing changes — people getting silently charged more. pain score 7.9"
• **SIG-20260425-us-micro-saas-utility-no-code-glue-overhead** (adjacent): solo founders gluing 8-15 SaaS subscriptions = exact target audience for spend visibility tool

Reasoning

The signal documented a 7.9 pain score in a 25K-complaint analysis, with explicit framing: "all came from real frustrations, all have existing competitors with terrible reviews." The FinOps incumbents (Vendr, Zylo, Spendflo) all targeted the enterprise tier in 2024-2025 raises — leaving the SMB/solo-founder tier completely uncovered. The product is structurally simple: a Chrome extension where users add the pricing-page URL of each SaaS they subscribe to; Celery polls daily; Claude Haiku diffs the HTML and produces a one-line "what changed" summary; users get an email when anything changes. Postgres + R2 store snapshot history. Build 7 days — the fastest project in this batch. Stack fits Railway + CF Pages cleanly. Recurring revenue is durable: $5/mo with near-zero churn while users have SaaS subscriptions; high LTV-to-CAC via Chrome Store discovery.

Quick competitive read

• **Visualping** ($50/mo for 200 pages) — generic page-monitoring, not SaaS-specific, no semantic alerts
• **Vendr** (quote-based, savings-share) — enterprise floor at $1M+ SaaS spend
• **Cledara** (quote-based mid-market) — requires virtual-card issuance + accounting integration
• **WatchThatPage** (free, legacy) — 2005-era UX, no semantics, free baseline pressure
• **A few Chrome SaaS-spend trackers** — track spend from bank statements, don't watch pricing pages

Market density: **medium-high (5+ players)** but every player is either enterprise-locked, requires controller-style card issuance, or is a generic non-semantic page monitor. White-space at the SMB tier with semantic "what changed" + extension-side polling + $5/mo flat. Competitive pressure scored 8 (high white-space).

Initial pricing hypothesis

$5/mo Solo (up to 30 SaaS subscriptions tracked) → $15/mo Team (up to 100, Slack alerts, multi-seat) → $39/mo Bookkeeper (multi-workspace, white-label reports). Low-price-high-volume, anchored on free Visualping alternatives + developed-tier WTP $10-100/mo.

Distribution hypothesis

Three waves:

1. **Chrome Web Store SEO** — "saas pricing tracker", "saas subscription alert" long-tail; near-zero CAC via Chrome discovery

2. **r/SaaS, r/sysadmin, r/Frugal posts** — "I built this because I got silently charged $300 more last month" relatable framing

3. **ProductHunt launch** + cross-post to Indie Hackers and LinkedIn FinOps groups