Skip to main content

2026-02-12

Receive only the on-chain events you want, in the format you want. Flexible Webhook fully customizes your Webhook with CEL-based filtering and selective output fields. From setting conditions to testing and failed message resending — all managed in one console.

Flexible Webhook​

The existing Classic Webhook provides fixed conditions and payloads for each event type. Flexible Webhook lets you define filter conditions directly with CEL expressions and receive only the fields you need. Create, test, and resend — all managed in one place from the console.

Supported Stream Types​

6 stream types are supported. Common to EVM-compatible chains, with the same structure across all supported chains.

  • Block — Block creation events
  • ERC-20 Transfer — ERC-20 token transfers
  • ERC-721 Transfer — ERC-721 NFT transfers
  • ERC-1155 Transfer — ERC-1155 multi-token transfers
  • Log — Smart contract event logs
  • Transaction Receipt — Transaction execution results

Key Features​

  • Precise Condition Builder: Configure filter conditions using Visual Mode (no-code UI) or Text Mode (CEL expressions). Supports AND/OR logic groups and provides blockchain-specific custom functions such as bigint_gt and address_eq.
  • Usable Templates: Frequently used condition patterns such as USDC Whale Transfer, Token Burn, and Failed Transaction are provided as Presets. When selected, conditions and output fields are automatically configured.
  • Live Testing: Validate your settings with real on-chain data before creating the webhook. Check recent events for the selected stream with Live Sample, and test endpoint delivery with Test Webhook.
  • Selective Output Fields: Directly select the fields to include in the webhook payload. Reduce payload size by excluding unnecessary fields.
  • Easy Resend: Select failed messages from the delivery history and resend them immediately from the console.

In addition, the Instant Webhook option allows you to receive messages quickly without waiting for block confirmation. The default is Off; when enabled, there is a possibility of data changes due to reorgs.

Security & Reliability​

  • Signature Verification: All messages include an HMAC-SHA256 signature in the x-signature header. The Signing Key can be viewed in the console.
  • Automatic Retry: If a 200 OK response is not received, one retry is attempted after 15 seconds.
  • Idempotency Support: Idempotency Key combinations per stream type are provided to prevent duplicate processing.

Documentation​