The small-SaaS stack you can host yourself.
28 open-source tools, each replacing a subscription a founder or small team usually pays for: booking pages, a help center, error tracking, feature flags, web analytics, lifecycle email, referral programs, Stripe revenue metrics and e-signature. Every one is MIT licensed, a zero-dependency Node server, and deployable to your own cloud with no vendor in between. Pick the one you need; none requires another.
Customers and support
| Tool | Instead of | What it does |
|---|---|---|
| Support Desk | Help Scout, Zendesk (shared inbox) | Email and contact-form tickets in one inbox, threaded by ticket number, with spam guesses that show their reasons and an overdue list for first replies. |
| Help Keeper | Help Scout Docs, Document360, Intercom Articles | Markdown help center with typo-tolerant ranked search, helpful votes and a report of searches that found nothing. |
| Survey Keeper | Typeform, SurveyMonkey, Delighted (NPS) | Surveys and Net Promoter Score with a 95% range, the words detractors use more than promoters, results by source, CSV export and an alert on every detractor. |
| Feedback Board | Canny, Nolt | Voting, duplicate detection as people type, a public roadmap and a ship-notification email. |
| Status Keeper | Statuspage, Better Stack status pages | HTTP and heartbeat checks, a public status page with 90-day uptime bars, incidents, maintenance windows and webhook alerts. |
| Changelog Keeper | Headway, Beamer | Release notes in safe Markdown, a public changelog, Atom and JSON feeds and an embeddable What's new bell. |
| Testimonial Keeper | Testimonial.to, Senja | A link customers use to write a testimonial with explicit publish consent, and an embeddable wall that shows only what you approved. |
Growth and marketing
| Tool | Instead of | What it does |
|---|---|---|
| Visit Keeper | Plausible, Fathom, Google Analytics | Cookie-free web analytics from a script under 1 KB: daily-rotating anonymous hashes, sources, UTM campaigns, goals with revenue. |
| Link Keeper | Bitly, Short.io | Short links on your own domain with UTM tagging, app-store routing, expiry and click stats without cookies or stored IPs. |
| Waitlist Keeper | Prefinery, Viral Loops | Launch waitlist with email confirmation, a referral ladder, anti-gaming guards, reward tiers and batch invites. |
| Drip Keeper | Customer.io, Loops | Event-triggered onboarding, trial and win-back email with goal events, send windows and one-click unsubscribe. |
| Referral Keeper | FirstPromoter, Rewardful | Referral and affiliate program on your own Stripe webhook: recurring commissions, clawbacks, hold periods and a payout CSV. |
| Form Inbox | Formspree, Basin | Point any HTML form at it for an inbox, visible spam scoring, CSV export and email or Slack notifications. |
| Slot Keeper | Calendly, Cal.com | Booking pages that respect your calendar's busy time, show slots in the visitor's zone and send invitations and reminders. |
| PQL Radar | product-qualified-lead scoring add-ons | Ranks new signups by first-week usage with a reason each, trained on your own conversions and validated out of time. |
Product and engineering
| Tool | Instead of | What it does |
|---|---|---|
| Error Keeper | Sentry, Rollbar | Crash grouping across deploys, alerts on new issues, regressions and spikes, from a 1 KB browser snippet or a Node client. |
| Flag Keeper | LaunchDarkly, Flagsmith | Sticky percentage rollouts, targeting rules, segments, a kill switch, an audit log and a local-evaluation SDK. |
| Webhook Relay | Hookdeck, Svix ingest | Verifies signatures from a dozen providers, saves each event before answering 200, retries with backoff and replays any event. |
Revenue and billing on Stripe
| Tool | Instead of | What it does |
|---|---|---|
| MRR Pulse | Baremetrics, ChartMogul | MRR, ARR, expansion, contraction and churn, net revenue retention and quick ratio from a read-only Stripe key. |
| Dunning Engine | failed-payment recovery add-ons | Classifies each decline code, retries only where a retry can work and emails a never-expiring update-card link. |
| Cancel Flow | Churnkey, ProsperStack | Asks why the customer is leaving, offers the save that fits the reason and reports save rate by reason. |
| Trial Converter | trial-nudge add-ons | Heads-up emails before a card is charged, escalating add-a-card emails for card-less trials and an optional extension. |
| Churn Radar | churn-prediction add-ons | A ranked at-risk account list with a reason each, trained on your own history and validated out of time. |
| Meter Keeper | Orb, Metronome | Idempotent usage events, tiered pricing, invoice previews and a retrying feed into Stripe Billing Meters. |
| License Keeper | Keygen, license-key add-ons | Ed25519-signed license keys your app verifies offline, machine limits, renewals and revocation on refund. |
| Rev Rec | revenue recognition add-ons | Spreads paid invoice lines over their service period into a deferred-revenue schedule and month-end journal entries. |
Sales and contracts
| Tool | Instead of | What it does |
|---|---|---|
| Deal Keeper | pipeline forecasting add-ons | Win rates learned from your own closed deals, a forecast with a 10th to 90th percentile band and a stale-deal hygiene list. |
| Sign Keeper | DocuSign, PandaDoc (simple cases) | Typed-name e-signature requests with a certificate holding the text's SHA-256 and a hash-chained audit trail. |
Run any of them yourself
git clone https://github.com/Duncan-Haywood/oss-monorepo && cd oss-monorepo/ventures/slot-keeper node --test ADMIN_KEY=$(openssl rand -hex 16) node server.mjs
Swap slot-keeper for any folder above. Each tool's page lists its settings, its honest limits, and Render, Fly.io and Docker deploy files.
Questions
Are these really free?
Yes. Every tool is MIT licensed. You pay only for wherever you choose to run it, which for most of them is a single small Node process on a free or low-cost host. There is no per-seat fee and no usage cap beyond your own server.
How do I deploy one?
Each tool is a zero-dependency Node server with a Dockerfile, a docker-compose file, and Render and Fly.io configuration. Clone the repository, open the tool's folder and run node server.mjs, or use the one-click deploy button where the tool's page offers it. Your data stays on the server you run.
How do these compare with Calendly, Sentry or LaunchDarkly?
They cover the core job a small team needs, not every feature of a paid platform. Each tool's page has an honest limits section naming what it does not do, for example single admin key instead of team logins. If you need enterprise permissions, audit certifications or a vendor to call, a paid product is still the right call.
Who maintains them?
They are built and maintained in the open in one repository, with automated tests for every tool. They are provided as-is, with no warranty and no uptime or delivery guarantee, so read the code and test it against your own needs before relying on it.
Can I use only one?
Yes. Each tool stands alone and shares nothing with the others. Those that talk to Stripe use your own webhook or a read-only key, and none of them needs another tool in this list.