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Chainhook Overview

Chainhook is a fork-aware transaction indexing engine aiming at helping developers focus on the information they need by helping with the on-chain data extraction. By focusing on the data they care about, developers work with much lighter datasets.

Chainhook can be used as a tool in your local development environment and as a service in the cloud environment.

What problem does it solve?​

Crypto applications can improve customer experiences by promptly delivering business outcomes in response to blockchain events. However, developers face significant time, energy, and operational overhead costs when running blockchain indexers and writing additional code to crawl through real-time blockchain events.

To address this issue, Chainhook takes away all that burden from developers, so they can focus on automating the trigger of predefined operations whenever blockchain events occur.

Features​

  1. Improved Developer Experience: instead of working with a generic blockchain indexer, taking hours to process every single transaction of every single block, developers can create their own indexes, build, iterate, and refine in minutes.

  2. Cost Optimization: developers avoid massive storage management and unnecessary storage scaling issues by avoiding full chain indexation. Also, chainhook helps developers create elegant event-based architectures. Developers write if_this / then_that predicates, being evaluated on transactions and blocks. When the evaluation of these predicates appears to be true, the related transactions are packaged as events and forwarded to the configured destination. By using cloud functions as destinations, developers can also cut costs on processing by only paying for processing when a block that contains some data relevant to the developer's application is being mined.

  3. Optimized User Experience: lighter indexes implies faster query results, which helps minimize end-user response time.

Chainhook Triggers​

With Chainhook, developers can trigger actions based on predicates they can write. Chainhooks support the following predicates non-exhaustively:

  • A certain amount of SIP-10 tokens were transferred.
  • A particular blockchain address received some tokens on the Stacks/Bitcoin blockchain.
  • A particular print event was emitted by a contract.
  • A particular contract was involved in a transaction.
  • A quantity of BTC was received at a Bitcoin address.
  • A POX transfer occurred on the Bitcoin chain.

Understand the Predicate Design​

Predicates are the conditions that you can define to scan the blocks easier and faster on a blockchain.

Predicates are defined in the If-this, then-that format. You'll write your condition in the if-this condition template and use then-that to output the result.

if-this Predicate Design​

The if-this predicate design can use the following attributes to define the predicates. The 'scope' parameter is mandatory to use with any of the other parameters.

  • scope (mandatory)
  • equals
  • op_return
    • ends_with
  • p2pkh
  • p2sh
  • p2wpkh
  • operation

Example:


{
    "if_this": {
        "scope": "txid",
        "equals": "0xfaaac1833dc4883e7ec28f61e35b41f896c395f8d288b1a177155de2abd6052f"
    }
}

then-that Predicate Design​

The then-that predicate design can use the following attributes to output the result based on the if-this condition defined.

  • http_post
    • url
    • authorization_header
  • file_append
    • path

Example:

{
    "then_that": {
        "file_append": {
            "path": "/tmp/events.json",
        }
    }
}

For more information on predicate definitions, refer to how to use chainhook with bitcoin and how to use chainhook with Stacks.