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Avasis ERC-20 Allowance Checker (Ethereum)
x402
Avasis ERC-20 Allowance Checker (Ethereum) is a paid API for AI agents from agents.avasis.ai, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-02).
Returns the current ERC-20 token allowance a spender has over an owner's tokens on Ethereum, with optional approval sufficiency check and ready-to-sign calldata.
Price / call$0.02
Success—
StatusUnknown
How this service works
Solana rug check + token risk score in one x402 call: $0.02 complete multi-source kit (verdict + holders + Jupiter + RugCheck + Dexscreener + consensus). Polymarket odds kit $0.02: event + books + history. Avasis is a research company building a platform made for agents: data an agent buys per call, x402 v1 + v2, USDC on Base, no account or API key. Headline calls: the $0.02 Solana rug check complete kit (is this token safe? token risk score from verdict + holders + Jupiter + RugCheck + Dexscreener + consensus in one payment; ax1 alternative), the $0.02 Polymarket odds complete kit (prediction market kit: event + books + history + every outcome with token ids + consistency checks in one payment), the $0.01 Solana token verdict (SAFE / WARN / DANGER from a deterministic on-chain rubric + share card + free receipt), the $0.002 web page reader (any public URL to clean markdown + metadata), $0.002 Polymarket markets (live odds, volume, liquidity). Other paid routes stay live and are listed in /.well-known/x402 and /pricing.md. Never charged on errors.
Output
A JSON object containing the current allowance (raw and human-readable), whether it is unlimited, the owner's token balance and USD exposure, the spendable_now amount, a verdict on whether the allowance is sufficient for the requested amount, any shortfall, ready-to-sign approve and revoke calldata, recognized names for the token and spender (e.g. USDC Circle, Uniswap Permit2), and a plain-English headline summarizing the situation.
Example use cases
Pre-swap approval check for DeFi
“Before I swap on Uniswap, check if my wallet 0x8fae03e3e0cb922297495bc22ee2a7c997f89b8d has enough USDC (token 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48) allowance for Permit2 (0x000000000022d473030f116ddee9f6b43ac78ba3) to cover 500 USDC, and give me the approve calldata if I need to top it up.”
Audit unlimited token approvals
“Check what allowance my address 0x8fae03e3e0cb922297495bc22ee2a7c997f89b8d has given to the Aave lending pool (0x7d2768de32b0b80b7a3454c06bdac94a69ddc7a9) for DAI (0x6b175474e89094c44da98b954eedeac495271d0f) on Ethereum — is it unlimited? If so, give me the revoke calldata.”
Risk check before bridge transaction
“I'm about to bridge WETH using the Stargate router (0x8731d54e9d02c286767d56ac03e8037c07e01e98) from my wallet 0xabc1230000000000000000000000000000000001 — can you check my current WETH (0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2) allowance and USD exposure, and tell me if I need to approve more?”
Technical details
Endpoint
GEThttps://agents.avasis.ai/v1/eth/erc20-allowance?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a single, structured, pay-per-call lookup of ERC-20 allowances on Ethereum without requiring an API key or account — especially useful for agents performing pre-trade safety checks, approval audits, or generating revoke/approve calldata before signing a transaction. Prefer it over raw RPC calls when you also want enriched metadata (known spender names, USD exposure, Permit2 flags, and ready-to-sign calldata) in one response.
Side effects
- Invalid or malformed owner/token/spender address returns a 400 error
- Token contract does not exist or is not ERC-20 compliant causes RPC call failure
- Network congestion or RPC timeout may delay response
- Unsupported chain identifier returns an error (only ethereum/1 on this route)
- Amount field with non-numeric value causes parsing error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"usd": {
"note": "exposure = spendable_now at the current price",
"price": 1,
"exposure": 11285.04,
"allowance": null,
"price_source": "stablecoin peg (known issuer)",
"owner_balance": 11285.04
},
"kind": "erc20-allowance",
"rail": "evm-rails-1",
"chain": "ethereum",
"check": {
"amount": "250",
"verdict": "READY: the spender can move this amount now",
"amount_raw": "250000000",
"needs_approval": false,
"shortfall_balance": "0",
"sufficient_balance": true,
"shortfall_allowance": "0",
"sufficient_allowance": true,
"approve_exact_calldata": null
},
"owner": "0x8fae03e3e0cb922297495bc22ee2a7c997f89b8d",
"reads": {
"rpc": "fixture",
"calls": 8,
"elapsed_ms": 0
},
"token": {
"known": "USDC (Circle)",
"symbol": "USDC",
"address": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
"decimals": 6,
"decimals_source": "decimals()"
},
"spender": {
"note": "Permit2 keeps its own per-spender allowances on top of this ERC-20 approval",
"known": "Uniswap Permit2",
"address": "0x000000000022d473030f116ddee9f6b43ac78ba3",
"permit2": true,
"is_contract": true
},
"calldata": {
"to": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
"from": "the owner",
"note": "approve(spender, amount) as 0x calldata, ready to sign from the owner; prefer an exact amount over unlimited; revoke = approve(spender, 0). Simulate first: /v1/<chain>/tx-precheck",
"revoke": "0x095ea7b3000000000000000000000000000000000022d473030f116ddee9f6b43ac78ba30000000000000000000000000000000000000000000000000000000000000000",
"approve_exact": null,
"approve_unlimited": "0x095ea7b3000000000000000000000000000000000022d473030f116ddee9f6b43ac78ba3ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
},
"chain_id": 1,
"headline": "USDC on Base: 0x8fae…9b8d allows Uniswap Permit2 UNLIMITED; balance 11,285.039971 (exposure $11,285.04); READY for 250",
"allowance": {
"raw": "115792089237316195423570985008687907853269984665640564039457584007913129639935",
"zero": false,
"amount": "115792089237316195423570985008687907853269984665640564039457584007913129.639935",
"unlimited": true,
"pct_of_balance": 100
},
"block_number": 53354727,
"owner_balance": {
"raw": "11285039971",
"error": null,
"amount": "11285.039971"
},
"spendable_now": {
"raw": "11285039971",
"note": "what the spender could move right now = min(allowance, owner balance)",
"amount": "11285.039971",
"limited_by": "balance"
},
"covers_full_balance": true
}
}Tags
x402
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