Wallet integration and onchain data indexing

0xJakess builds the layer between wallets, contracts and your database: Sign-In with Ethereum with server-side checks, embedded wallets through Privy or Coinbase CDP alongside RainbowKit, and Goldsky pipelines that stream contract events into Postgres. This work runs in production on Welcome3, AtlasOra and TraderChamber.

See all work

Updated 28 October 2026

What's included

Connect, prove ownership and keep the database in step with the chain.

Wallet sign-in and ownership proofs, embedded smart accounts with a paymaster, external wallets through RainbowKit, and indexing pipelines that stream contract events into Postgres.

Sign-in with EthereumServer-issued nonces and server-side signature checks, used to verify NFT holdings.
Wallets inside your appCustodial or non-custodial wallets built into the product with Privy or Coinbase CDP, alongside traditional wallet connectors.
Event indexingGoldsky pipelines and Alchemy reads for bookings, releases and refunds.
Read-only verificationEncrypted API keys and per-venue request signing to verify trading volume.

Shipped work

Welcome3

CTO

The Project: A private, invite-only network of Web3 founders, investors and operators, connected through warm introductions.
What I Built: The platform end to end: applications, member directory and network map, intros, events and feed
Realtime chat with typing indicators, and Telegram login through a custom OIDC bridge
NFT community badges, verified by wallet signature against holdings
An admin suite of 20+ screens and a locked-down Postgres schema
Outcome: Live as the members' home for introductions, events and a weekly roundup.

ROLE: CTO
MIGRATIONS: 100+
ADMIN SCREENS: 20+

Visit Welcome3(opens in a new tab)

AtlasOra

CTO

The Project: Vacation rentals across Europe without hidden fees. Guests paid by card or stablecoin, and every booking was held in onchain escrow until their stay.
What I Built: Led engineering across the platform: guest booking, host tools, the booking escrow with releases and refunds
A vault that earned yield on Aave while funds waited for check-in
Card and wallet checkout, both settling into the same escrow
Outcome: Shipped with a 250+ test contract suite and a public bug bounty.

NETWORK: BASE
YIELD: AAVE V3
TESTS: 250+

Visit AtlasOra(opens in a new tab)

TraderChamber

CTO

The Project: A verified network connecting active traders with the exchanges, perp DEXs and prediction markets built for them.
What I Built: Most of the product UI
Chamber Points with the team: tiers, boosts and the weekly emission
Trading competitions, with an always-on worker streaming live exchange fills into the standings
Outcome: Season 0 is live, with traders verifying real volume across 37+ venues and earning points every week.

VENUES: 37+
WEEKLY POOL: 100K PTS

Visit TraderChamber(opens in a new tab)

Questions

How do you add Sign-In with Ethereum to an app?

The server issues a single-use nonce, the wallet signs a SIWE message containing it, and the server verifies the signature and nonce before creating a session. Ownership checks, such as verifying NFT holdings, run server-side against the verified address.

Can users get a wallet without installing one?

Yes. Embedded wallets from Privy or Coinbase CDP create a custodial or non-custodial wallet at sign-up, and a paymaster can cover gas, while RainbowKit still serves users who bring their own wallet.

How do you keep a database in sync with a smart contract?

Contracts emit an event for every state change, and an indexing pipeline such as Goldsky streams those events into Postgres. The app reads from the database for speed and treats the chain as the source of truth.

How do I hire 0xJakess for wallet or indexing work?

0xJakess is open to new builds. Message 0xJakess on Telegram at t.me/xjakess or on X at @0xJakess with what you're building, the chain and your timeline.

Building something onchain?

Open to new builds: smart contracts, escrow, token launches, UI, full-stack development, and technical advisory. Tell me what you're building.