Simple Feature Flag Endpoint for Small Apps
Toggle features, roll out to a percentage of users or a named list, and read flags from a fast cached JSON endpoint with a tiny SDK.
Economics
- Pricing example
- $9/month per project (free: 5 flags, 1 environment)
- Daily math
- 67 projects x $9/month = about $600/month, or $20/day.
- Target if you hit the daily math
- Target: $600 / month at about 67 paid projects
Audience and urgency
Audience: Indie developers and small teams shipping web and mobile apps.
Urgency: Small teams want to ship behind a switch and roll back without redeploying, but full feature-management platforms take time to set up and learn.
MVP scope
- ✓ Flags per environment: boolean, percentage rollout, user-ID allow list
- ✓ Cached JSON endpoint per environment with client-safe and server keys
- ✓ Tiny JS SDK with deterministic hashing for percentage rollouts
- ✓ Audit log of flag changes
- ✓ Stripe subscription
Omitted features
- - Do NOT build experimentation statistics or A/B analysis
- - Do NOT send user data to the server for evaluation (evaluate in the SDK)
- - Do NOT build complex targeting rules in Day 1
Suggested stack
- Frontend
- Next.js + Tailwind CSS
- Backend or API
- Cloudflare Workers + KV for the flag endpoint; Postgres for the dashboard and audit log
- Payments
- Stripe Billing
- Hosting
- Cloudflare Workers + Pages
Repository metadata
- Blueprint ID
feature-flag-json-endpoint- Category ID
dev_tools- Monetization ID
micro_subscription
Day-one distribution
Channels
- Reddit r/webdev and r/SaaS (follow rules)
- Hacker News 'Show HN'
- dev.to tutorial: shipping behind a flag in 10 minutes
Reddit strategy
Share the free tier and a short guide to percentage rollouts.
Cold outreach or directory hook
List on developer tool directories with an honest comparison to open-source options.
Search keywords
simple feature flags, feature flag service cheap, percentage rollout javascript
One-shot master prompt
Build a "Simple Flags" service: Next.js dashboard, Cloudflare Worker endpoint and a JS SDK.
Core requirements:
1. Dashboard (magic link): projects, environments (dev/staging/prod), flags with type boolean, percentage (0-100) or allow-list of user IDs, and descriptions.
2. On every change, write the environment's compiled flag JSON to Cloudflare KV and log the change (who, what, before/after) in Postgres.
3. Worker endpoint GET /v1/flags/{envKey} returning the JSON with Cache-Control and ETag; client keys only see client-safe flags.
4. SDK (under 2 KB gzipped): init(envKey), isEnabled(flag, userId) using a stable hash (e.g. murmurhash of flag+userId) for percentages, polling or manual refresh, and a local default fallback.
5. Stripe Billing ($9/month per project); free tier limits enforced in the dashboard.Comparable products
Published 2026-10-08.
Related blueprints
Changelog Page from GitHub ReleasesConnect a repository and get a hosted, branded changelog page, RSS feed and a small 'What's new' widget generated from your GitHub releases.Cron Job Heartbeat MonitorGive each scheduled job a ping URL and get an email or Telegram alert when it fails or does not check in on time.Email Test Inbox for DevelopersPoint a staging app's SMTP settings at a shared test inbox, and preview every caught email's HTML, text, headers and links without any of them reaching real users.Env File Diff & Validator CLICompare .env files across local, staging and production and validate them against a schema in CI, without ever printing secret values.