A private Bitcoin network built for learning — where every cohort can build, experiment, and break things without consequences.
Timeline: 2-week MVP · Team: ~12 students across 4 squads + QA
You know how Bitcoin works — people send coins, transactions get confirmed in blocks, and the whole thing runs on a global network. But what if you could have your own version of that entire network — one that's free to use, instant, and completely safe to experiment with?
That's what this is.
Plan B Signet Playground is a private Bitcoin network run by Plan ₿ Network. It behaves exactly like the real Bitcoin network — same rules, same transaction format, same everything — except:
- The coins have no real value (so you can't lose money)
- Blocks are created instantly (no 10-minute waits)
- We control it (so we can tailor it for learning)
Think of it like a flight simulator for Bitcoin. Everything feels real, but you can't crash.
- Get free test sats from the faucet — onchain or over Lightning
- Win sats by answering Bitcoin questions in the daily quiz
- See your transactions live in the block explorer
- Connect your own wallet (Sparrow, a Lightning wallet that supports custom Signet)
- Build apps on top of it — wallets, payment tools, anything you'd build on real Bitcoin
It's permanent. Every new cohort picks up where the last one left off.
Bitcoin already has test networks, but they all have trade-offs for education:
| Network | How Fast? | Who Can Join? | Who Runs It? | Good For |
|---|---|---|---|---|
| Real Bitcoin | ~10 min per block | Everyone | Nobody (decentralized) | Real money |
| Testnet | ~10 min per block | Everyone | Nobody | General testing |
| Our Custom Signet ✦ | Instant ⚡ | Plan B students & guests | Us | Learning |
| Regtest | Instant | Just your computer | You alone | Solo practice |
The problem with Testnet is it's slow (10 minutes between blocks) and public (random people spam it). Regtest is fast but it's solo — you can't practice with classmates.
Our Custom Signet is the best of both: instant blocks and a shared network where everyone can interact.
On the real Bitcoin network, miners compete to create blocks using massive computing power. On our network, we skip all that. Instead, we use a digital key — whoever holds this key can create a new block instantly, on demand.
This is what makes it a "Signet" — blocks are signed (approved) by a specific key instead of being mined. The rest works identically to real Bitcoin: same transaction rules, same addresses, same wallet software.
In plain terms: We have a master key that lets us press a "create block" button whenever we want. Students' transactions follow the real Bitcoin rules — our key just decides when those transactions get confirmed.
Right now, one person holds the signing key (simple to manage). In the future, we can require 2-out-of-3 people to agree before creating a block — teaching governance and shared responsibility.
The MVP is built by four squads + a QA track, each owning one folder. Pick a squad, read its README, ship.
| Squad | Folder | Mission | Status |
|---|---|---|---|
| 1 — Faucet | faucet/ |
Self-service onchain + Lightning faucet | 🔴 open slots |
| 2 — Daily Quiz | quiz/ |
Daily BTC quiz that pays out sats | 🔴 open slots |
| 3 — Infrastructure | infrastructure/ |
Custom Signet, LND, LNbits on VPS | 🟢 staffed |
| 4 — Website & Docs | website/ |
Public front door + onboarding | 🔴 open slots |
| QA | qa/ |
Cross-squad testing & UX sign-off | 🟡 1 slot open |
Each squad picks its own stack. Cross-squad contracts (RPC endpoints, API URLs, network params) are published by Squad 3 in infrastructure/runbook.md.
Here's the flow when a student uses the playground:
Student opens the website (Squad 4)
│
▼
"I need test sats" ──► Faucet (Squad 1) ──► Bitcoin node (Squad 3)
│ │
▼ ▼
"I want to send onchain Block signer creates a block
to a classmate" ─────────► bitcoind ◄────── (transaction is now confirmed)
│
▼
"I want to win more sats" ──► Daily Quiz (Squad 2) ──► LNbits payout (Squad 3)
│
▼
QA verifies the whole flow works for an external student.
A more complete component view lives in docs/architecture.md.
This is a monorepo. Each squad owns one top-level folder; project-level docs live in docs/.
planb-signet-playground/
├── README.md ← you are here
├── PURPOSE.md ← vision, principles, definition of done
├── .gitignore
│
├── infrastructure/ ← Squad 3
│ ├── README.md
│ └── runbook.md ← restart/debug the network without asi0
│
├── faucet/ ← Squad 1
│ └── README.md
│
├── quiz/ ← Squad 2
│ └── README.md
│
├── website/ ← Squad 4
│ └── README.md
│
├── qa/ ← cross-squad testing
│ └── README.md
│
└── docs/
└── architecture.md ← system overview diagram
Each squad README documents its own goal, deliverables, stack, dependencies, and team.
A new external student lands on the website, follows the tutorial, gets sats from the faucet, plays the quiz, and wins sats — all on custom Signet, with no human in the loop. The infra survives a VPS reboot via documented runbook. QA has signed off on the happy path for all three webapps.
Full criteria in PURPOSE.md.
The MVP is just the foundation. Once it's solid, we'll layer on:
| Phase | What | Why |
|---|---|---|
| MVP (current) | Custom Signet · onchain + LN faucet · daily quiz · website · QA sign-off | Get external students transacting end-to-end |
| Phase 2 | Cashu ecash faucet · richer educator toolbox · Mempool.space instance | Broaden the surface students can play with |
| Phase 3 | Ark · Fedimint · multi-signer block-signing governance | Explore L2/L3 and shared responsibility |
| Phase 4 | RGB / smart contracts · Plan B webapp wallet for custom Signet | Build anything on Bitcoin |
- Read
PURPOSE.mdanddocs/architecture.md. - Open your squad's folder and read its
README.md. - Open issues / PRs against your squad's folder only — coordinate before touching shared concerns.
Head to the website and follow the onboarding. You'll need:
- A Bitcoin wallet that supports custom Signet (e.g. Sparrow)
- A Lightning wallet that supports custom Signet (TBD — see
docs/architecture.md)
We welcome contributions from Plan B students, alumni, and the broader Bitcoin community. Issues are tagged per squad (squad/faucet, squad/quiz, squad/infra, squad/website, squad/qa); pick one and dive in.