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Dictionary

Token Approval

A token approval grants a contract permission to move your tokens — persistent, often unlimited, and the most common source of avoidable losses.

2 min readupdated 2026-09-02

/ quick answer

ERC-20 style tokens require an allowance before a contract can transfer them. Wallets default to large or unlimited allowances for convenience, so a later exploit or a malicious contract you approved months ago can still drain that token. Periodic approval review and revocation is basic hygiene for any active wallet.

A token approval grants a contract permission to move your tokens — persistent, often unlimited, and the most common source of avoidable losses. ERC-20 style tokens require an allowance before a contract can transfer them. Wallets default to large or unlimited allowances for convenience, so a later exploit or a malicious contract you approved months ago can still drain that token. Periodic approval review and revocation is basic hygiene for any active wallet. In practice: Revoking an unlimited approval to a DEX router you last used a year ago, before a proxy upgrade turns it into a liability. This dictionary node is part of the Onexial knowledge graph and links to related concepts, workflows and tools below.
Definition
ERC-20 style tokens require an allowance before a contract can transfer them. Wallets default to large or unlimited allowances for convenience, so a later exploit or a malicious contract you approved months ago can still drain that token. Periodic approval review and revocation is basic hygiene for any active wallet.
Example
Revoking an unlimited approval to a DEX router you last used a year ago, before a proxy upgrade turns it into a liability.
/ frequently asked

What is Token Approval?

ERC-20 style tokens require an allowance before a contract can transfer them. Wallets default to large or unlimited allowances for convenience, so a later exploit or a malicious contract you approved months ago can still drain that token. Periodic approval review and revocation is basic hygiene for any active wallet.

What is an example of Token Approval?

Revoking an unlimited approval to a DEX router you last used a year ago, before a proxy upgrade turns it into a liability.

Why does Token Approval matter for AI and automation?

A token approval grants a contract permission to move your tokens — persistent, often unlimited, and the most common source of avoidable losses. It connects to the workflows, prompts and tool stacks linked on this page, so you can move from definition to execution without leaving Onexial.

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Related concepts

The vocabulary this page depends on.

  • Web3 Wallet

    A Web3 wallet stores your keys and signs transactions, letting you hold assets and connect to on-chain applications without an intermediary.

  • Self-Custody

    Self-custody means you control the private keys to your assets, so no company can freeze, lend out or lose them on your behalf.

  • Seed Phrase

    A seed phrase is the 12–24 word backup from which every private key in a wallet is derived — whoever holds it holds the wallet.

  • Private Key

    A private key is the secret number that authorises transactions from an address; the public address is derived from it, never the reverse.

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Related workflows

Turn this into a repeatable process.

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Related tool stacks

The tools that run it in production.

  • AI Security Stack

    Least-privilege tooling, approval gates and audit trails for agentic systems.

  • AI Agent + Web3 Stack

    Agent framework, MCP/API tools, blockchain data access and a limited signing layer — with policy enforced in code.

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Related prompts

Reusable prompts for this job.

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Related use cases

How people apply it, and what came out.

  • Use DeFi With A Web3 Wallet

    A first-time DeFi user moved from an exchange to self-custody with a test-transfer routine and a 2% allocation cap, avoiding two protocol failures.

  • Monitor Wallet Transactions

    Alerting on the user's own wallet activity caught an unauthorised approval attempt and forced an approval cleanup that removed 14 standing allowances.

  • Automate Repetitive Web3 Actions

    Automating reward claims and gas top-ups with session keys and spend caps saved about 5 hours per month with no unbounded authority.

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Comparisons & alternatives

Pick between the options.

  • Hot Wallet vs Cold Wallet

    Hot wallets trade convenience for exposure; cold wallets trade friction for a signing key that never touches an internet-connected device.

  • Rabby vs OKX Web3 Wallet

    Rabby is the safety-focused EVM wallet with pre-transaction simulation; OKX Web3 Wallet trades some of that depth for multi-chain breadth and built-in trading.

  • MetaMask vs OKX Web3 Wallet

    MetaMask is the EVM default with the widest DApp support; OKX Web3 Wallet bundles multi-chain coverage, a DEX aggregator and exchange integration in one app.

  • Phantom vs OKX Web3 Wallet

    Phantom is a Solana-first wallet with best-in-class UX on that ecosystem; OKX Web3 Wallet is a generalist multi-chain wallet for users spread across networks.

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