Instant credit tabs on any chain

Open a tab, let users spend now, then settle after 7 days with non-custodial, collateral-backed guarantees.

Non-custodial collateral

Funds stay on-chain with the user until settlement

BLS-backed guarantees

Cryptographic proofs for each spend request

Settle after 7 days

Users pay later without prefunding balances

ETH, USDC, USDT

Default assets with versioned guarantees

Explore the platform

How it works

Three steps to instant spend

Plain flow first, cryptographic guarantees underneath

01

Recipient opens a tab

Create a tab_id with asset and limits for a user

02

User spends on credit

Users sign guarantees per request with no prefunding

03

User settles after 7 days

Settle later, or claim collateral after the on-chain grace period

Benefits

Built for developers who ship fast

Start with plain UX. Add verifiable credit guarantees when you are ready.

  • Users spend now and settle after 7 days
  • No prefunding or prepaid balances for customers
  • Every charge is backed by on-chain collateral
  • BLS-signed guarantees prevent replay and double spend
  • Default assets: ETH, USDC, USDT with versioned guarantees

Docs

Start with tabs, ship in a day

Quickstart, SDKs, and API endpoints for /tabs, /verify, and /settle

Start BuildingBrowse Docs

Minimal flow

Recipient: POST /tabsopen tab
Agent: POST /settlecredit guarantee
Agent: payTabInERC20TokenT+7 days

SDKs: Rust, TypeScript, Python

Quick StartPayer + Recipient Flow
1import { Client, ConfigBuilder, PaymentGuaranteeRequestClaims, SigningScheme } from "sdk-4mica";
2
3async function run() {
4 const cfg = new ConfigBuilder()
5 .fromEnv()
6 .walletPrivateKey(process.env.PAYER_KEY!)
7 .build();
8
9 const client = await Client.new(cfg);
10
11 const claims = PaymentGuaranteeRequestClaims.new(
12 userAddress,
13 recipientAddress,
14 tabId,
15 amountWei,
16 Math.floor(Date.now() / 1000),
17 assetAddress,
18 reqId
19 );
20
21 const signed = await client.user.signPayment(claims, SigningScheme.EIP712);
22 console.log(signed.signature);
23}
24
25run();
Payer and recipient flow examplesSDK + API ready

Use cases

Built for developer-first products

Drop tabs into any flow where usage is real time and settlement can wait

API monetization

Meter requests in real time and settle after 7 days without prepaid balances

Infra and AVS compute

Let builders run workloads now and pay later with verifiable guarantees

Agentic commerce

Wallets and agents can transact instantly while collateral backs every spend

Powering

Our early partners

Collaborators integrating payment tabs and credit-backed UX

EigenAligned LayerVistaraChaosChain

Open-source core

Contracts and SDKs are public on GitHub

Testnet live

4Mica is now live on the testnet

Non-custodial design

Collateral stays on-chain until settlement or claim

Security model

Plain UX, hard guarantees

Keep funds on-chain and verify every claim before collateral moves

  • Non-custodial collateral stays in Core4Mica until settlement or claim
  • Guarantees are BLS-signed with domain separation and versioned configs
  • AccessManaged roles, Pausable, and ReentrancyGuard protect critical flows

Community

Build the payment tab standard

We are building in public with developers who ship infra. Join the discussion, open issues, and help shape the protocol.

Join CommunityStart Building
Join the DiscordStar on GitHubBuild with usRequest early access

About Us

The credit layer for instant, on-chain commerce

4Mica issues cryptographic payment tabs that keep capital productive while delivering real-time UX. We help teams monetize APIs, AVS services, and on-chain commerce without forcing users to pre-fund every request.

4Mica Mission

Mission, product focus, and how 4Mica unlocks credit-backed payments

Learn more

Team

Meet the founders building the payment layer for instant commerce

Learn more

Roadmap

Track delivery milestones for the credit layer and network rollout

Learn more

Resources

One-Pager

Concise overview of 4Mica's real-time, non-custodial payments stack and value proposition

Learn More

Technical Documents

SDK usage, facilitator and operator APIs, plus protocol flow references for teams and developers

Learn More

Blog

Product updates, practical guides, and perspectives on 4Mica payments and infrastructure

Learn More

FAQ

Common questions

Defaults are pulled from Core4Mica contract parameters.

What is a payment tab?

A tab is a credit line identified by tab_id. The recipient opens it, and req_id tracks each spend against the tab.

What is a payment guarantee?

A guarantee is a BLS-signed claim with tab_id, req_id, client, recipient, asset, amount, total_amount, timestamp, and a domain separator.

When can recipients claim collateral?

After the remuneration grace period (default 14 days) and before tab expiration (default 21 days). Claims outside that window revert.

When do users settle?

The product flow asks users to settle after 7 days. If they do not, the on-chain claim window opens at 14 days by default.

How do withdrawals work for users?

Users request a withdrawal, then finalize after the withdrawal grace period (default 22 days). A synchronization delay (default 6 hours) protects tabs opened near a withdrawal request.

Which assets are supported by default?

ETH, USDC, and USDT are supported. Stablecoin flows require USDC or USDT; other assets revert.

Ready to build with payment tabs?

Start building or join the community and help define the standard.

Start BuildingJoin Community