Built on Tempo

TIP-20 stablecoin rails

Every Fluxus balance and transfer uses TIP-20 stablecoins (pathUSD and USDC.e) with 6-decimal precision. Person-to-person payments attach 32-byte on-chain memos via transferWithMemo, which powers transfer notes, POS receipts, and the in-app message threads. Balances are read with a single Multicall3 aggregate, never native-token lookups.

• pathUSD · 0x20c0000000000000000000000000000000000000
• USDC.e · 0x20C000000000000000000000b9537d11c60E8b50

Fee sponsorship: gasless by default

Fluxus sponsors gas for every user transaction through a server-side fee payer composed with the Tempo Accounts SDK (Handler.compose([webAuthn, feePayer])). Sponsored fills are signed above audited per-operation gas floors so the chain never rejects a sponsor-filled transaction:

A typical sponsored transfer costs well under a tenth of a cent (for example 849,110 gas × 0.6 gwei ≈ $0.000509 in pathUSD), and the fee payer covers it. Verified on mainnet: 0x4f5751ec…34803765 (Tempo fee-sponsored transaction type 0x76). The dashboard's "Sponsored & saved" widget shows each user the fees the sponsor has covered for them, and On-chain Proof collects further receipts.

MPP: machine payments over HTTP 402

Fluxus monetizes machine-facing endpoints with the Machine Payments Protocol (co-authored by Stripe and Tempo): a request without payment receives an HTTP 402 challenge, an MPP client settles it in pathUSD, and the retried request returns the resource plus a signed Payment-Receipt. Current route pricing (imported from the live handler):

• schedule · 0.02 pathUSD
• send · 0.01 pathUSD
• stream · 0.02 pathUSD

# 1. Request without payment → HTTP 402 + WWW-Authenticate: Payment (challenge)
curl -i -X POST https://fluxuspay.app/api/mpp/send \
  -H "content-type: application/json" \
  -d '{"to":"0x...","amount":"0.10","memo":"agent payment"}'

# 2. Settle the challenge with an MPP client (mppx / pympp / mpp-rs),
#    then retry with the credential:
curl -i -X POST https://fluxuspay.app/api/mpp/send \
  -H "content-type: application/json" \
  -H "Authorization: Payment <credential>" \
  -d '{"to":"0x...","amount":"0.10","memo":"agent payment"}'
# → 200 + Payment-Receipt response header

Replay protection: credentials are single-use; replayed credentials are rejected at the verification layer and logged.

Tempo Accounts SDK: passkeys and scoped keys

Authentication is passwordless: WebAuthn passkeys create and control Tempo accounts through the Tempo Accounts SDK. On top of the root passkey, Fluxus exposes protocol-native scoped access keys (wallet_authorizeAccessKey) with per-token spend caps, expiry, and one-click revocation: the foundation for two shipped surfaces:

• Security Center with programmable spending policies and a receive-policy preview.
• Agent budgets to give the AI payment agent a spend-capped, expiring pathUSD allowance; every transfer still requires explicit user approval.

T6 / T7 network-upgrade alignment

Tempo's 2026 network upgrades map directly onto the Fluxus roadmap:

• T6: receive policies & admin access keys. The Security Center ships a receive-policy editor today (token and sender allow/blocklists) as a clearly-labeled local preview; on-chain enforcement (including recoverable held transfers instead of reverts) activates as SDK support lands. Scoped access keys are live now.
• T7: dynamic fees & storage credits. T7's dynamic base fee lowers typical transfer fees by up to ~95% at the floor (network estimate, not yet measured on Fluxus traffic). The "Sponsored & saved" widget surfaces per-user sponsored fees today; a T7-aware sponsorship optimizer (timing repeated MPP/subscription state around storage-credit reuse) is on the roadmap.

Roadmap

Items below are planned, not live; anywhere they appear in the app they carry an explicit preview or roadmap label:

• On-chain receive-policy enforcement (T6) with a held-payment recovery inbox.
• Live oracle price feeds and depeg alerts on token asset profiles.
• Automated reserve-attestation freshness checks for pathUSD.
• T7 storage-credit-aware fee sponsorship optimizer.
• Durable MPP payment sessions (persistent channels, cold resume, replay).
• Multi-provider ramp and local-currency settlement routing.