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Kaito Platform API/Fee Estimation/
Estimate network fee for...

Kaito Platform API (2.0.0)

Platform services including webhooks and blockchain gateway operations.

Webhooks: Register endpoints for event notifications. Kaito signs requests using HMAC-SHA256 with Kaito-Timestamp and Kaito-Signature headers. Events include payment, payout, quote, checkout, identity, and acceptance categories.

Chain Gateway: Low-level blockchain operations for Ethereum, Polygon, Solana, and Bitcoin. Includes fee estimation and transaction broadcast for partners managing their own key material.

Download OpenAPI description
platform.json
platform.yaml
Overview
URL
https://developer.kai2.io/support
Kaito Developer Support
support@kai2.io
License
Apache 2.0
Terms of Service
Languages
Servers
Mock server
https://developer.kaito.io/_mock/platform/
Production
https://api.kai2.io/
Sandbox
https://sandbox.api.kai2.io/

Webhook Endpoints

Manage webhook subscriptions

Operations

Event Types

List available event types

Operations

Fee Estimation

Estimate network fees

Operations

Estimate network fee for a transfer

Request

Estimate the network fee for a transfer. Returns fee estimates for different speed tiers (slow, standard, fast).

Security
oAuth2
Bodyapplication/jsonrequired
networkstring(Network)required
Enum"ethereum""polygon""solana""bitcoin"
fromstringrequired

Sender address

tostringrequired

Recipient address

assetstringrequired

Asset symbol (e.g., USDT, ETH)

Example: "USDT"
amountstringrequired

Amount to transfer

Example: "10.0"
curl -i -X POST \
  https://developer.kaito.io/_mock/platform/v1/chain/estimate-fee \
  -H 'Authorization: Bearer <YOUR_TOKEN_HERE>' \
  -H 'Content-Type: application/json' \
  -d '{
    "network": "ethereum",
    "from": "string",
    "to": "string",
    "asset": "USDT",
    "amount": "10.0"
  }'

Responses

Fee estimate

Headers
X-Trace-Idstring(TraceId)

Correlation id for troubleshooting

Example: "trc_01JH8K5P3V9M2K5Q7W6J3Z1A9B"
Bodyapplication/json
networkstring(Network)required
Enum"ethereum""polygon""solana""bitcoin"
estimatedFeeobject(FeeEstimate)required
estimatedFee.​amountstring
Example: "0.12"
estimatedFee.​currencystring

Native currency of the network

Example: "MATIC"
estimatedFee.​tierstring(FeeTier)
Enum"slow""standard""fast"
Example: "standard"
alternativesArray of objects(FeeEstimate)

Fee estimates for other tiers

Response
application/json
{
  "network": "ethereum",
  "estimatedFee": {
    "amount": "0.12",
    "currency": "MATIC",
    "tier": "standard"
  },
  "alternatives": [
    { … }
  ]
}

Transaction Broadcast

Broadcast signed transactions

Operations