Fairground

A social network with no company in the middle. Advertisers and fans pay creators directly, every deal is a signed public record anyone can check, and readers control their own feed algorithm. The social network uses distributed storage and a static app. Optional card/bank integrations require an approved payment gateway with a fixed IP; the near-$0 hosting plan explores free-tier and contributor-run gateways, with a small-server deployment available as a paid fallback.

Status: early release. The protocol core, the web app and the Android and iOS projects are built and tested. Try it at evolvetech.dev/play/fairground. Payments are real USDC; use small amounts while it matures.

Easy first

Most decentralized networks lose people at the start, because new users have to understand keys, relays and wallets before they see anything good. Fairground is designed for the least technical reader and has to be enjoyable within seconds:

• No setup. Opening the app creates an account silently. Readers never see keys, relays or wallets; a wallet comes up only when someone gets paid. A username and password, for using the account on other devices, are offered later.
• A good feed immediately. The default is an AI "For you" feed drawn from the whole network, so a newcomer with no follows still sees the best posts. One optional tap on a few topics points it in the right direction.
• It learns from normal use. Likes, posts read for a few seconds and "less like this" tune the reader's profile on their device. There are no settings to learn, though every setting is there for those who want it.
• One kind of account. Anyone can post, earn, advertise, run a survey or run a relay, and creators keep the same feed as everyone else.

How it works

Its own network, built on Nostr's plumbing. A post is an event signed by its author's key and stored on independent relays that anyone can run, the way Nostr works. But Fairground is its own network: the app shows only Fairground accounts (every account joins by publishing its post-quantum key binding on first start), never the wider Nostr network, so its spam and abuse never arrive and the first creators here aren't drowned out. The app is a static site, and the same code ships as the iOS and Android apps (Capacitor). Creators own their identity and audience: there's no account to be banned from and no cut.

Readers own their algorithm. Ranking runs on the reader's device from a recipe they control:

• which signals count and how much (newness, people they trust, engagement, topics, AI similarity);
• whether sponsored posts show, sink or disappear;
• how varied the feed is;
• which words to mute.

Recipes are plain data, so they can be shared, forked and safely run from anyone, and every post shows why it's there. The default ranks with a small embedding model that runs in the browser (Transformers.js, about 23 MB, downloaded once); readers can switch to their own Ollama model or turn AI off. Nothing about their reading leaves the device.

Sponsorships are four signed events: an advertiser's offer, the creator's acceptance, the creator's post (disclosed with #ad) and the advertiser's payment receipt. The acceptance pins and embeds the exact offer, so terms can't change afterwards. Anyone can advertise, including a creator cross-promoting with another creator. Creators publish media kits (rate, topics, audience survey) so advertisers can find them, and advertisers' payment records (delivered, paid, overdue, days to pay) are public, so creators can see who pays before accepting.

A wallet built in, and dollars in and out of a bank. Every account has a wallet: an Algorand account whose key is derived from the account's own key, so the backup code and the username-and-password vault restore it, and payments are signed on the device in one tap. Nobody else, Fairground included, can move the money, and Fairground funds no one's wallet. Card purchases and bank withdrawals use a server-created Meld checkout with explicitly configured suppliers and native Algorand currency IDs. Card purchases always buy ALGO, which any wallet can receive; the first one also pays for setup (USDC opt-in and a reserve), and the wallet converts the rest to USDC through Folks Router after checking every transaction the router asks it to sign. Paying or donating needs no balance: the payer buys just enough ALGO, by card or from an exchange, and their wallet turns it into the exact USDC payment and closes in the same step, so nothing is left behind and only people who keep a balance, get paid or cash out set a wallet up. Cash-outs are configured separately, so buying can open first; their instructions are fetched from Meld using the saved checkout session and checked against the wallet, owner and exact amount again before signing. Providers handle KYC and payment details. Live routes still require Meld credentials and supplier eligibility; see Meld integration. External wallets and exchange transfers remain available independently of card/bank checkout. Wallet, Add money and payment screens include copyable addresses, QR codes and exchange instructions; see Use crypto you already own.

Payment goes straight to the recipient's wallet, in USDC on Algorand, from the built-in wallet or through an ARC-26 link that opens the payer's own wallet. The project never holds or splits funds. Each transfer's memo names what it's for (a deal, fan support, a donation), so the app finds it on the public chain and anyone can verify every flow.

Prices hold their purchasing power. Offers, rates and support amounts are set in dollars of a base month and scaled by the US CPI-U when paid, never below nominal. Index values arrive as signed attestations, published monthly from the BLS by tools/publish-index.ts; each client chooses which publishers it trusts and how many must agree.

Contracts are quantum-resistant. Contract events carry an ML-DSA-65 (FIPS 204) signature alongside Nostr's Schnorr signature, so a future quantum computer that can forge Schnorr signatures still can't forge a deal. Creators receive into Algorand accounts that can sign with Falcon-1024, live on mainnet since August 2026.

Audience surveys replace tracking. Fairground is anonymous by default. A creator who wants to show sponsors their audience asks in plain language, with standard questions (age range, region). Each answer goes out separately, at a random time, from a throwaway key, carrying a token the creator signed without seeing it (blind RSA, RFC 9474). Nobody can link an answer to a person, while advertisers can recount the answers and see if there are more than participants.

Fans can pay for work without ads. A support page offers a suggested monthly amount, an optional goal, and an optional ad-free pledge: after a month when supporters meet the goal, no sponsorships the next month. Supporters pay anonymously, and anyone can total the month and check the pledge from the chain.

A marketplace for goods, food and services. Listings use NIP-99 classifieds, so other Nostr marketplaces show up too. They can be things for sale, menu items, services (rides, grocery runs, meal pickup, tasks, cleaning) or requests for help that people answer with a price. Sellers can open a shop, a restaurant with a menu, or a services page. Orders and offers travel as end-to-end encrypted messages (NIP-17), and buyers pay the seller's wallet directly. Only someone who paid can review: the payment memo carries an order id that commits to the buyer. Reliability shows verified orders and ratings, weighted towards reviewers the reader trusts. Credentials (licence, insurance, food handler card, background check) show as verified by organisations the reader trusts, vouched by people they follow, or self-declared.

Every format in one app. Posts read like Twitter, Photos like Instagram, Videos like YouTube (a grid, then a watch page with what's next), Shorts like TikTok (full-screen, swipe, plays what's on screen) and Listen like a podcast app, with the Market alongside. They use the standard formats (NIP-68 pictures, NIP-71 videos, NIP-F4 podcast episodes), and ordinary posts with a photo, video or audio link show in the matching format, so there's something to watch from the first day. Anyone can post in any format: photos are shrunk and stripped of location data on the device, and videos are uploaded with their length, size and a poster frame read on the device. On a computer the app has a sidebar, wide grids and a side column, rather than a stretched phone layout.

Podcasts in every podcast app. A creator starts a show (artwork, category, explicit flag) and uploads episodes, marking natural pauses where mid-roll ads can go. Each show gets a standard RSS feed with the iTunes and Podcasting 2.0 tags, served by a podcast gateway, that they paste once into Apple Podcasts, Spotify, YouTube Music and Podcast Index. The gateway (src/gateway.ts, about 100 KB bundled) is a stateless request handler that reads signed events from relays, so anyone can run one; the one at evolvetech.dev/fairground runs as a Netlify edge function. It serves only Fairground accounts, applies the same always-blocked rules as the app, and lets its operator take a show down. Episodes are ordinary MP3 or M4A files, which every app accepts from any publisher. HLS streams play in the app and are listed as a Podcasting 2.0 alternate enclosure; Apple Podcasts' own HLS video is open only to hosting providers Apple has approved, through a private API, so the feed never depends on it.

Host-read ads, inserted dynamically. An advertiser plans a campaign (goal, offer and promo code, talking points, what not to say, formats and slots, audience, budget at a price per thousand listens, dates and brand-safety exclusions) and the app matches it to creators' media kits. Each creator gets an offer with their own promo code and tracked link. A creator who accepts reads the ad in their own voice, recorded in the app or uploaded, and publishes a placement: the recording, its slots (pre-, mid- or post-roll), its dates and the shows or videos it runs on. If the offer asks, the advertiser approves that exact recording first. Nothing is baked in: Fairground's player inserts the read while it plays (labelled with the sponsor, skippable, as Apple also requires of ads), and the gateway stitches it into MP3 downloads for every other app, splicing MPEG frames at the creator's marks without re-encoding and supporting the HEAD and byte-range requests Apple requires. So a read runs across the whole back catalogue, starts and stops on its dates, and gives way to the next sponsor. Reads recorded in the app are converted on the device to MP3 matching the show's episodes. The campaign page tracks every creator from offer to paid, and turns the orders and revenue each promo code brought in into cost per order and return on spend.

Search. Search covers Fairground accounts only: the app fetches their recent posts, profiles and listings and matches on the device, so what a reader searches for stays with them. Results go through the same safety rules as the feed.

Reddit-style comments everywhere. Posts, photos, videos, shorts, episodes and listings have threaded replies with up and down votes, Best, Top, New and Controversial sorting, and collapsible branches.

Safe by default. Nostr relays carry everything anyone posts, so the app decides what to show:

• Sexual content involving minors, bestiality and intimate imagery shared without consent are never shown, and their authors are blocked.
• Safe search hides explicit content by default. Adults can turn it off after confirming they are 18 or older; in the phone apps that's only possible on the web, as the app stores require.
• Only Fairground accounts appear, which keeps out the spam and abuse that circulate on the wider Nostr network.
• Slurs, threats, spam and bots are hidden, and every post can be hidden or reported. Titles and image descriptions are checked as well as the text.
• Posts are in the reader's languages: their device's, plus any they keep reading, liking or writing in, detected on the device. That keeps the start feeling like their own community rather than the whole world at once. Languages can be added or removed in settings, or the filter turned off.

The commons loop. After money changes hands (a creator's payout, an advertiser's payment, a seller's paid order, a month of fan support) the person is offered an optional donation, never pre-selected, and anyone can give from You or About at any time. Development donations go to the project's public USDC account on Algorand, which the app offers only once it can receive USDC. Donors see exactly how it splits between development and relays, and which relays get it: the ones that actually served them, starting with relays run by their own followers. Anyone can run a relay and receive donations by publishing a payout address that their relay's NIP-11 document confirms. Relays can pledge to pass a share back to creators. The loop is damped so it can't be farmed: relays are credited only for events they delivered first to readers who saw them, credit is grouped by operator, and each hop passes on a small share (about 0.2% of a deal per round trip).

Sign in anywhere without a server. A username and password derive, through Argon2id, a key that finds and decrypts the account's vault on relays: keys, settings, AI interests, subscriptions, payout details, survey keys. A passkey (WebAuthn PRF) can be required as a real second factor, with a recovery code as fallback.

Limits

• "No hosting cost" applies to the project. Relays and media hosts are run by others. Free relays may drop old events and video is expensive to store, so serious creators will want a paid relay or their own.
• Phones can't be relays. Relays must accept connections around the clock, so running one means a server, a home machine or a hosting service. The app does everything else in one step.
• Quantum resistance doesn't yet cover the whole stack. It covers the contracts and the creator's own account. Algorand's consensus (target 2027) and USDC's issuer keys are still classical, and ordinary posts are Schnorr-only. Once Schnorr can be forged, deciding which key binding came first needs a timestamp anchored before then (NIP-03); that is not implemented yet.
• USDC holds dollar value, not purchasing power. Indexing protects the deal, not a balance kept afterwards. No cost-of-living stablecoin is liquid and stable enough to pay with today; the settlement rail is named in each offer.
• Index publishers are trusted. A value counts only when the client's threshold of trusted publishers agree and none disagree. Until independent publishers exist, the default trusts one (the project's), which could set a value.
• No escrow, no verified listen counts. The advertiser pays after the post goes up or the read runs, with the public payment record as the enforcement. Deals are a flat fee; listen counts in media kits are what creators report, and promo codes are how an advertiser checks them. The gateway doesn't count downloads yet.
• The built-in wallet uses Ed25519 keys, not post-quantum ones. Algorand's native Falcon-1024 accounts use a deterministic Falcon signature that general-purpose JavaScript libraries don't produce (we checked: Algorand rejects a standard Falcon signature). The wallet can be rekeyed to a Falcon key, keeping its address, once a compatible signer exists. Contracts stay hybrid-signed, and anyone can be paid into a Falcon account in Pera instead.
• Keeping a balance means a one-time setup, paid from the first deposit. About five cents of it stays as ALGO for Algorand's account minimum and fees, and converting the rest costs the router's 0.1% plus the exchange's fee and a little price movement (at most 0.5% below the quote, or the conversion fails). The provider's minimum purchase applies.
• Paying without a balance buys about 3% more ALGO than the payment, against conversion costs and prices moving during checkout, plus 0.24 ALGO for minimums and fees; whatever is left goes to the recipient with the payment. Each card payment pays the provider's fee, so someone who pays often is better off keeping a balance, and a provider's minimum purchase can rule out small card payments. If prices move more than the buffer, the payment waits for a little more ALGO, or the payer keeps what arrived as a balance.

Development

Node.js 22.18 or later. The protocol core runs as TypeScript with no build step; the app builds with Vite.

npm install
npm test                  # protocol core: 135 unit tests
npm run typecheck
npm run app:dev           # the app on http://localhost:5173
npm run app:build         # static build in app/dist
node tools/dev-relay.ts   # an empty local relay; open the app with ?relay=ws://localhost:7777
node e2e/smoke.ts         # end-to-end test of the built app in Chrome, against labelled test fixtures
node e2e/market.ts        # two people: comments, safety, buying, requests, offers and orders
node e2e/media.ts         # photos, videos, shorts, listening, search, languages, and the desktop and phone layouts
node e2e/podcast.ts       # a show and episode, a campaign, a recorded read, approval, playback, RSS and stitching, donating
node e2e/wallet.ts        # a first deposit setting up a wallet, paying in one tap, cashing out, donating, paying without a balance (stand-ins)
npm run gateway:build     # bundles the podcast gateway into dist-gateway/fairground-gateway.js

The app reads public relays by default. ?relay= (repeatable) points it elsewhere, and a build with VITE_READONLY=1 reads real relays without publishing anything, for testing.

Mobile apps

app/android and app/ios are Capacitor projects that load the same web build.

npm run app:build && (cd app && npx cap sync)
(cd app/android && ./gradlew assembleDebug)   # needs the Android SDK and JDK 21
(cd app && npx cap open ios)                  # needs macOS and Xcode

Store releases need signing keys and developer accounts, which aren't part of this repository.

Operations

• CPI attestations: .github/workflows/index.yml publishes mid-month. Generate the publisher key once with node tools/publish-index.ts --keygen > publisher.json, store it as the FAIRGROUND_INDEX_KEY secret, and keep the public key in src/defaults.ts in step.
• Development fund: DEVELOPMENT_ADDRESS in src/defaults.ts is Anthony Firn's built-in Fairground wallet. Its first ALGO deposit enables USDC through the normal wallet setup. Until it can receive USDC, donations go only to relays. The same Fairground account and backup restore access to this wallet.

Path	Contents
src/pq.ts	Hybrid Schnorr + ML-DSA-65 signatures, key bindings and rotation
src/pricing.ts	Indexed prices, index attestations and the k-of-n trust rule
src/sponsorship.ts	Offer, acceptance, sponsored post, payment receipt; deal and payment checks
src/mediakit.ts	Creators' media kits and advertisers' public payment records
src/survey.ts	Audience surveys: blind tokens, throwaway-key answers and an independent recount
src/support.ts	Fan support pages, monthly totals and the ad-free pledge check
src/commons.ts	Donations to development and relays, relay payouts, anti-farming credit, pass-on pledges
src/comments.ts	Threads (NIP-10 and NIP-22), votes (NIP-25), Reddit-style ranking
src/commerce.ts	Listings (NIP-99), storefronts, orders, quotes, verified reviews, credentials, reports
src/safety.ts	Illegal-content blocking, safe search, spam and bots, languages
src/network.ts	Fairground membership: the key bindings that make an account part of the network
src/podcast.ts	Shows, episodes, Apple categories and RSS feeds
src/ads.ts	Campaigns, host-read placements, approvals and dynamic ad breaks
src/mp3.ts	MP3 frame layout, for splicing reads in without re-encoding
src/gateway.ts	The gateway: podcast feeds, stitched downloads with Range support, Meld checkout sessions, health
src/walletkey.ts, src/wallet.ts	The built-in wallet: key derivation, balances, USDC payments signed on the device
src/algotx.ts	The two Algorand transactions Fairground makes, encoded byte-for-byte as the network expects (checked against the Algorand SDK in tests)
src/swap.ts	Converting ALGO and USDC through Folks Router, with every transaction checked before signing

License

Apache License 2.0