ZK Circuits & Verifiers (Noir, Circom)

I will build zero knowledge circuits in Noir or Circom with on-chain verifiers

Jedidiah GabrielProduct engineer · Kaduna, Nigeria · Replies within 24 hours

ZK Circuits & Verifiers (Noir, Circom) flyer: Math that keeps a secret.

About this gig

A zero-knowledge circuit is a program whose output can be trusted without seeing its inputs. Getting one right takes care: a single missing constraint can let anyone forge a proof.

I write circuits in Noir and Circom from a precise statement of what's public and what's private, test them against forgery attempts, and generate verifiers for the chains you need: Solidity for Ethereum and L2s, or Cairo for Starknet through Garaga, which supports Groth16 on BN254 and BLS12-381 and Noir's UltraKeccakHonk.

What you get:

A written statement of public and private inputs
Circuits in Noir or Circom, with tests that try to break them
Proving-time and gas benchmarks, with optimisations
Verifier contracts in Solidity and/or Cairo
Integration code for your app or backend
A review of an existing circuit, if you have one

I build on Starknet and EVM chains, including Bilateral Escrow, LandReg3 and Tongo shielded balances in WeSelling.

Send me what you need to prove, or the circuit you want reviewed.

Use cases

Membership proofs

Merkle-tree membership with nullifiers, the base for anonymous voting, claims and feedback.

Range and threshold checks

Prove a value sits in a range (age, balance, score) without revealing it.

Credential checks

Verify a signed credential's fields inside the circuit and reveal only the ones you choose.

Porting and review

Move a Circom circuit to Noir, or review constraints for under-constrained signals.

What changes

Today

Your protocol needs privacy, and nobody on the team writes circuits
Proofs take too long to generate or cost too much to verify
An existing circuit may be under-constrained, and nobody has checked
You need the same proof verified on more than one chain

After

Circuits written from a precise statement of public and private inputs
Proving time and verification gas measured and reduced
Generated verifiers in Solidity, or in Cairo through Garaga
Constraint tests, including deliberate attempts to forge proofs

How it works

01Define public and private inputs
02Write the circuit
03Test constraints and forgery
04Generate verifiers
05Integrate and benchmark

Compare packages

Package	Starter$600	Business$1,600	Scale$4,200
What it is	One small circuit (membership, range or credential) with tests and a verifier	Up to 3 circuits, benchmarks, verifiers and app integration	Circuit suite, verifiers on two chains, Circom-to-Noir port or review, docs
Circuits	1	Up to 3	Up to 6
Language	Noir or Circom	Noir or Circom	Both if needed
Constraint and forgery tests	✓	✓	✓
Verifier contracts	1 chain	1 chain	2 chains
Benchmarks and optimisation	–	✓	✓
App or backend integration	–	✓	✓
Circom to Noir port or circuit review	–	–	✓
Audit-ready documentation	–	–	✓
Delivery	8 days	16 days	30 days
Revisions	2	3	4

Add-ons

Faster delivery+30% of the package
Internal security review with written findings+$250
Written documentation for your team+$50
90 days of support and small changes+$240

Built before

WeSelling shielded balancesBusinesses on WeSelling can move resting USDC into a Tongo pool on Starknet so their treasury can't be read on a block explorer. The product states what that privacy covers and what it doesn't.weselling.store Bilateral EscrowOpen-source Cairo contract that holds a buyer's payment and a merchant's return bond until delivery terms are met.github.com

Who it's for

Protocols adding privacy
Identity and credential projects
Voting platforms
Teams porting Circom to Noir

What I'll need from you

What needs to be proven, with public and private inputs if you know them
Target chains
Existing circuits or contracts, if any
Performance needs: proving device and time budget

Questions, answered

Noir or Circom?

Noir for most new work: readable, Rust-like, with in-browser proving and verifiers on Ethereum and, through Garaga, on Starknet. Circom when you need Groth16's small proofs or an existing Circom library.

Do circuits need an audit?

If they protect money or identity, yes. I write tests that try to forge proofs and prepare documentation an auditor can work from.

Who owns the code and accounts when we finish?

You do. Code goes to your repository, and services run on accounts in your name, so you are never locked to me. I hand over logins, keys and a short guide.

What if my project doesn't fit a package?

Send a message describing what you need. I reply with a custom offer priced to the actual scope, often after a short call.

The thinking behind it

Prove It Without Showing ItZero-knowledge proofs let users prove income, membership or location without handing over the data. Jedidiah Gabriel on zkTLS with Reclaim, browser proofs with Noir and Garaga, custom circuits and privacy pools.