The first synchronously composable appchain on Celo, the Ethereum Layer 2 built for the real world and designed for fast, low-cost transactions, is now live.
Through a new collaboration between Spire, cLabs, and Self Protocol, this appchain is powered by Self’s zero-knowledge Proof of Humanity and built using Pylon, Spire’s platform for synchronous composability. The launch demonstrates how appchains can now natively verify onchain human identity without sacrificing user privacy.
Together, we’ve unlocked a new class of applications that support compliant stablecoin usage, privacy-preserving eligibility and sanctions verification, and age-gated experiences while keeping user data protected.
Try the live demo and claim your Human NFT:
Human NFT
Claim your Human NFT - Mint your "I am human" NFT on Pylon appchain
To build the onchain economy, we need to create a connected and unified Ethereum.
As Ethereum scales, fragmentation has become a growing challenge. Users, liquidity, and data are increasingly siloed across layers and chains, forcing new networks to bootstrap liquidity, rebuild user bases, and duplicate infrastructure. Users are left navigating degraded UX and frequent bridging. A unified chain experience enables new applications to scale globally by delivering seamless product experiences to users.
Synchronous composability is the foundation of this unified chain experience. Rather than relying on asynchronous messaging, delayed settlement, or external bridges, synchronous composability allows applications to read and act on shared state in real time, within a single transaction.
To bring this vision to life, we’re introducing a new appchain on Celo with Self, enabling anyone to use onchain human identity while preserving user privacy.
The Human Appchain uses synchronous reads to verify users' unique humanity directly on Celo. Users maintain privacy of their identity data, attestations are enforced onchain, and access to the commemorative NFT is limited exclusively to verified humans.
The launch demonstrates how appchains can now natively verify onchain human identity without building custom identity or sybil-resistance infrastructure from scratch. This opens up a range of opportunities for new onchain applications:
Stablecoin usage (e.g. USDT) with identity guarantees
DeFi with real-world credit score
Privacy-preserving eligibility and sanctions verification
Age-gated and compliance-ready experiences
Secure wallet recovery via verified identity
Fair airdrops and rewards with built-in sybil resistance
Appchains have emerged as the next phase of blockchain scaling, giving teams dedicated blockspace, custom execution environments, and application-specific performance and economics. But appchains shouldn’t live in isolation. With Pylon, appchains remain sovereign at the application layer while staying composable with Ethereum L2s like Celo. This lets builders focus on product, UX, and differentiation while inheriting shared infrastructure for liquidity, identity, and security. The Human Appchain demonstrates this model by composing directly with existing identity primitives instead of rebuilding them.
Self paired with Pylon enables a verified identity single sign-on experience for app developers on their own chain. Together, they create an identity layer that appchains can tap into when they choose to build on Celo.
The app is open-source on GitHub and demonstrates how any developer can seamlessly read from Celo in their smart contracts as if they were deployed on the same chain. See the docs and start building.
Celo is the leading Ethereum L2 by DAUs, with a community of over 700K users leveraging the network in their everyday lives. Having launched on mainnet Earth Day 2020, Celo is a battle-tested chain with an ecosystem committed to scaling blockchain through frontier tech. As early adopters of fee abstraction (stablecoins as gas payment), ZK infrastructure, and pioneers of mobile-first infra, the Celo community is primed for the next wave of innovation: synchronous composability.
Self Protocol provides privacy-preserving Proof of Humanity and identity verification through its zero-knowledge infrastructure enabling users to prove properties about themselves, such as uniqueness, age, or nationality without revealing underlying personal data. Instead of exposing identity details, users generate attestations simply confirming their eligibility that applications can verify. This ensures users retain custody of their identity while applications receive only what they need to enforce access, compliance, or eligibility.
Today, Self supports 8M+ users with support for biometric government-issued passports and ID cards across 129 and 35 countries, respectively. Self also supports onboarding via the Indian Aadhaar, used by 99% of the adult Indian population, making it one of the most widely accessible identity systems globally.
The Human Appchain is the easiest way to experience how privacy-preserving Proof of Humanity works natively within an appchain.
This launch is only the first step. Verified human identity will increasingly underpin stablecoins, DeFi, consumer applications, and compliance-ready onchain experiences. Appchains combined with synchronous composability bring these capabilities to users through seamless, unified experiences.
If you’re building on Ethereum and exploring appchains, identity, or synchronous composability, contact us.
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