Understand the key concepts behind Agnic - X402, wallets, tokens, and transaction flows.

Core Concepts

Before diving into the API, it helps to understand the key concepts that power Agnic.

The X402 Protocol

X402 is a proposed HTTP status code (like 404 for "Not Found") that means "Payment Required". When an API returns 402, it includes authorization instructions that tell the client how to access the resource.

How X402 Works

┌─────────┐                    ┌─────────┐                    ┌─────────┐
│  Your   │  1. Request data   │ X402    │                    │ Agnic   │
│  App    │ ────────────────>  │  API    │                    │  Pay    │
│         │                    │         │                    │         │
│         │  2. 402 + terms    │         │                    │         │
│         │ <───────────────── │         │                    │         │
│         │                    │         │                    │         │
│         │  3. Sign authz     │         │                    │         │
│         │ ────────────────────────────────────────────────> │         │
│         │                    │         │                    │         │
│         │  4. Authz proof    │         │                    │         │
│         │ <──────────────────────────────────────────────── │         │
│         │                    │         │                    │         │
│         │  5. Request + proof│         │                    │         │
│         │ ────────────────>  │         │                    │         │
│         │                    │         │                    │         │
│         │  6. 200 OK + data  │         │                    │         │
│         │ <───────────────── │         │                    │         │
└─────────┘                    └─────────┘                    └─────────┘

Why X402?

Traditional APIs	X402 APIs
Sign up for each service	One wallet for all APIs
Manage multiple API keys	Use-per-request, no subscriptions
Monthly billing cycles	Instant microtransactions
Manual approval needed	Automated transactions

Authorization Schemes

Agnic supports two X402 authorization schemes:

Exact Scheme (EIP-3009)

How it works: TransferWithAuthorization - funds transfer exactly on use
Best for: One-time transactions, precise billing
Chains: Base (EVM), Solana

Upto Scheme (EIP-2612)

How it works: Permit - pre-authorize up to an amount
Best for: Streaming responses, variable costs
Chains: Base (EVM)

Agnic automatically detects and handles both schemes.

Wallets

Embedded Wallets

When you sign up, Agnic creates an embedded wallet for you using Privy. This wallet:

Is non-custodial (you control the keys)
Works on Base and Solana
Holds USDC for transactions
Supports delegation for automated signing

Delegation (Session Signers)

To enable automated transactions, you delegate signing authority to Agnic:

You set spending limits (per-transaction, daily, monthly)
You sign a delegation message
Agnic can sign authorizations within your limits
You can revoke access anytime

Delegation never gives Agnic access to your full balance - only the ability to sign authorizations within your specified limits.

API Tokens

API tokens authenticate requests to Agnic. Each token has:

Property	Description
`maxPerTransaction`	Maximum USD per single transaction
`dailyLimit`	Total USD allowed per 24 hours
`monthlyLimit`	Total USD allowed per 30 days
`networks`	Allowed networks (Base, Solana)
`label`	Your custom label

Token Types

Prefix	Type	Use Case
`agnic_tok_`	API Token	Direct API access
`agnic_at_`	OAuth Access Token	User-authorized apps
`agnic_rt_`	OAuth Refresh Token	Refresh access tokens

Spending Limits

Spending limits protect you from unexpected charges:

Per-Transaction Limit: $1.00
├── Blocks any single transaction > $1.00
└── Useful for capping AI response costs

Daily Limit: $10.00
├── Resets every 24 hours
└── Prevents runaway automation

Monthly Limit: $50.00
├── Resets every 30 days
└── Budget control for long-term use

Networks

Agnic supports multiple blockchain networks:

Network	Token	Use Case
Base (Mainnet)	USDC	Production transactions
Base Sepolia	USDC (testnet)	Development/testing
Solana	USDC	Production transactions
Solana Devnet	USDC (devnet)	Development/testing

OAuth tokens are restricted to mainnet networks only (Base, Solana). API tokens can access testnets.

Credits

New users receive $5 in free credits. Credits are used before your wallet balance and:

Core Concepts

Core Concepts

The X402 Protocol

How X402 Works

Why X402?

Authorization Schemes

Exact Scheme (EIP-3009)

Upto Scheme (EIP-2612)

Wallets

Embedded Wallets

Delegation (Session Signers)

API Tokens

Token Types

Spending Limits

Networks

Credits

Next Steps

Quickstart

X402 Fetch

API Reference

On this page