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USDC support engine for self-hosted platforms

Per-second and one-off support on Circle x402 and Arc

Build Passing Version License Node.js TypeScript Circle x402 Arc Testnet

TL;DR

Tessera sits next to your self-hosted platform so audiences can support creators and instance hosts in USDC: an optional tip on free content, or per-second support on exclusives.

A platform plugin loads the Tessera overlay and tells the sidecar when someone starts, stops, or tips. You install that plugin on the platform.

The Problem

Self-hosted platforms give communities ownership, but they leave a gap: there is no native way for audiences to support the infrastructure and creators they value.

Stakeholder Pain Point
Instance Administrators Bear 100% of infrastructure costs (servers, storage, bandwidth) with few tools beyond donations or ads
Creators Publish on platforms they do not control, with no built-in path to direct support from their audience
Viewers / Readers Want to support people they follow, but platform-wide subscriptions do not match what they actually consume

Instances shut down when admins can no longer afford them. Creators move to commercial platforms. Communities fragment.

The Solution

Tessera is a USDC support engine: a sidecar next to your platform, plus a plugin that loads the overlay. Free items stay open (tessera:free) with a manual tip. Exclusive items ask for a USDC deposit, then bill by the second while the viewer stays.

flowchart LR
    subgraph Client
        V((Viewer / Fan))
    end

    subgraph Server
        T{Tessera Sidecar}
        P[Self-Hosted Platform]
    end

    subgraph Financial Layer
        C[Circle x402 Gateway]
        W((Creator's Wallet))
    end

    V -- "1. Consumes Content" --> P
    P -- "2. Plugin events" --> T
    V -. "3. Tip or per-second support" .-> T
    T -- "4. Batches and settles" --> C
    C -- "5. USDC to creator" --> W

    style T fill:#ffb300,stroke:#333,stroke-width:2px,color:#000
    style W fill:#6C63FF,stroke:#fff,stroke-width:2px,color:#fff

How support works:

  • Free content (tessera:free): no lock, no billing. Tip is manual only
  • Exclusive content: viewer deposits USDC, then per-second support while they stay. Leave and replay do not freeze the player
  • Gas-free ticks: the sidecar authorizes a nanopayment each second; settlement is batched
  • Cross-chain funding: viewers can fund via Circle CCTP; settlement is on Arc Testnet

How It Works

sequenceDiagram
    actor Viewer
    participant Paywall as paywall.js
    participant Plugin as PlatformPlugin
    participant Sidecar as TesseraSidecar
    participant Circle as CircleUCW_Gateway

    Viewer->>Paywall: opens content
    Paywall->>Circle: email or social plus SCA
    Paywall->>Sidecar: POST /api/core/circle/prepare-deposit
    Circle-->>Paywall: USDC deposit challenge
    Paywall->>Sidecar: POST /api/core/sync-session or register-session
    Plugin->>Sidecar: HMAC POST /api/core/v1/sessions/start
    loop Every second while connected
        Sidecar->>Circle: Gateway pay to creator
    end
    Plugin->>Sidecar: HMAC POST /api/core/v1/sessions/stop
    Note over Sidecar: Funds stay in Gateway
    Viewer->>Paywall: optional cash-out
    Paywall->>Sidecar: POST /api/core/cash-out

In plain terms:

  1. Viewer opens content → The platform plugin loads the Tessera overlay (paywall.js).
  2. Viewer funds support → Circle UCW (email OTP or social) creates an SCA on Arc Testnet. Exclusive content uses POST /api/core/circle/prepare-deposit (USDC) and a Circle challenge.
  3. Session key → The overlay calls POST /api/core/sync-session (returning viewer) or POST /api/core/register-session (new key). Both prove Circle wallet ownership. Register may also deposit leftover SCA USDC into Gateway.
  4. Support ticks off-chain → The plugin sends HMAC-signed POST /api/core/v1/sessions/start. Each second Tessera authorizes a nanopayment to the creator payoutAddress. POST /api/core/v1/sessions/stop (also HMAC) ends billing.
  5. Viewer leaves → Funds stay in Gateway. A manual POST /api/core/cash-out returns unused USDC to the viewer's SCA. Tips use POST /api/core/v1/tips with Circle proof.

HMAC header details and the connector contract: Connector spec.

Integrated Platforms

Tessera is live on PeerTube, Jellyfin, and Piwigo. Plugin install lives in each repo: Integrated Platforms.

Tech Stack

Technology Purpose Why It Matters
Circle x402 Gateway Batched settlement USDC support as small as $0.000001 using HTTP 402
Circle UCW SDK Smart Contract Accounts on Arc Testnet Non-custodial wallets with email OTP or social login
Circle CCTP Forwarding Cross-chain USDC bridging (Domain 26) Viewers can fund USDC from a supported source chain
Arc Testnet Settlement layer (Chain ID 5042002) Native USDC gas, sub-second finality
EIP-3009 Off-chain transfer authorization Gasless signatures for per-second ticks
viem Type-safe EVM interactions TypeScript library for chain calls
Express Web application server Node.js HTTP for the sidecar

Architecture Summary

Tessera uses a sidecar pattern. Two layers in this repo:

Core Engine (src/core/) - Session management, per-second billing, wallet ops, Circle Gateway / x402.

Client Overlay (src/ui/) - Overlay UI. Platforms load it from /assets/.

Platform plugins live outside this repo and call the HTTP contract.

Diagrams, fees, and settlement: docs/ARCHITECTURE.md.

What This Enables

  • Creators get direct support (tips on free items, per-second on exclusives). Earnings accumulate in Gateway, then the creator withdraws to their wallet
  • Admins can take a configurable share on time-based content to help cover hosting
  • Viewers tip only if they want on free content, and pay only for the seconds they watch on exclusives. No platform-wide subscription

License

Apache-2.0 - see LICENSE for details.