Ad Midnight

The $600B digital ad industry is built on a broken promise: you must surrender your identityto receive relevant ads. We built AdMidnight to make privacy the load-bearing wall — not a marketing claim

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Inspiration

The $600B digital ad industry is built on a broken promise: you must surrender your identity to receive relevant ads. Cookie deprecation, GDPR, and Apple ATT have exposed this model's collapse. We built AdMidnight to make privacy the load-bearing wall — not a marketing claim.

What it does

AdMidnight is a privacy-preserving programmatic ad protocol on Midnight Blockchain:

  • AI Track: Users' devices run a local AI model to match ads. A ZK proof of the match is generated on-device using Midnight's Compact circuits. Raw browsing data never leaves the device — ever.
  • DeFi Track: Advertisers submit sealed bids via Pedersen commitments (H(bid||nonce)). The auction settles via ZK proof — the winner is proven without revealing losing bids. Users receive anonymous rewards via nullifiers — no wallet address linked to browsing.

How we built it

  • Compact smart contracts: AdMatchRegistry, AdAuction, UserReward — three circuits on Midnight
  • NestJS backend: Clean Architecture, SOLID principles, provider pattern per Midnight SDK v4.0.4
  • Next.js dashboard: Advertiser campaign management with Lace wallet integration
  • Flutter mobile app: On-device ZK proof generation, anonymous reward claiming

Challenges we ran into

Accomplishments that we're proud of

  • First known implementation of ZK-verified ad impression counting on Midnight
  • Complete sealed-bid auction with ZK settlement proof
  • SOLID/DRY/Clean Architecture throughout — production-grade codebase

What we learned

  • Midnight's three-context model (Witness → Circuit → Ledger) maps perfectly to ad-tech data flow
  • The Plonk/BLS12-381/JubJub proof system imposes field constraints on circuit design
  • Privacy-by-architecture is fundamentally different from privacy-by-policy

What's next for Ad Midnight

  • OpenZeppelin FungibleToken integration for NIGHT/DUST reward token
  • Lace wallet full integration for transaction signing
  • Deploy to Midnight Testnet (Preprod)
  • Build Club accelerator application

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