Managing Sentio Processors

Overview

Sentio SDK is a TypeScript blockchain data indexing platform. Processors handle on-chain events, transactions, and state changes across Ethereum, Aptos, Sui, Solana, Starknet, Bitcoin, Cosmos, Fuel, and IOTA.

Reference examples: See sentioxyz/sentio-processors for 120+ production processors.

When to Use

• Creating/initializing a Sentio indexing project
• Adding contracts or ABIs to a project
• Writing processor code for any supported chain
• Testing processors with TestProcessorServer
• Deploying processors with sentio upload
• Configuring sentio.yaml
• Multi-chain or multi-contract setups
• DeFi protocols (DEX, lending, staking, points systems)

Progressive Disclosure

This skill follows a layered approach:

1. This file — CLI commands, core patterns, all handler types, metrics/events/store overview, best practices
2. references/advanced-patterns.md — Multi-contract binding, GlobalProcessor, lazy caching, view calls, partition keys, baseLabels
3. references/defi-patterns.md — Price feeds, DEX/AMM, lending protocols, TVL tracking, Aptos/Sui DEX helpers
4. references/store-and-points.md — Store schema advanced features (relationships, timeseries, indexes, iterators, filter operators)
5. references/position-tracking-templates.md — 10 protocol-specific points/position tracking templates (Simple Holding, Aave, Morpho, Vault/LP, Uni V3, Pendle, Compound, NFT, Uni V2, Uni V4)
6. references/production-examples.md — 7 complete production processor examples (Uniswap, AAVE, Cetus, LiquidSwap, Lombard points, Scallop)

Project Lifecycle

sentio create → sentio add → sentio gen → write processor → sentio test → sentio upload → sentio processor status

1. Initialize Project

npx @sentio/cli create <project-name> --chain-type <type> --chain-id <id>

2. Add Contracts & Generate Types

sentio add <address> --chain <chain> --name <Name>   # Downloads ABI, updates sentio.yaml
sentio gen                                             # Generate TypeScript bindings
sentio build                                           # Full: gen + typecheck + bundle

3. Login & Deploy

sentio login                              # OAuth browser flow (prod)
sentio login --api-key <key>              # API key auth

sentio upload                             # Build + deploy
sentio upload --skip-build                # Deploy only
sentio upload --continue-from <ver>       # Hot-swap without re-indexing
sentio upload --checkpoint "1:18000000"   # Rollback to specific block
sentio upload --num-workers=4             # Parallel workers for compute-heavy processors

4. Verify Processor is Running

After upload, use sentio processor status --project / to check the processor status. If the processor is in ERROR state, use sentio processor logs --project / --level ERROR to get error details, diagnose the issue, fix the code, and re-upload.

package.json

Recommend yarn over npm. With npm you may hit BaseContract / DeferredTopicFilter type conflicts (TS2344 due to duplicate ethers).

{
  "name": "project-name",
  "type": "module",
  "scripts": {
    "build": "sentio build",
    "gen": "sentio gen",
    "upload": "sentio upload",
    "test": "sentio test"
  },
  "dependencies": {
    "@sentio/sdk": "^3.4.0"
  },
  "devDependencies": {
    "@sentio/cli": "^3.4.0",
    "typescript": "^5.4.5"
  }
}

If using npm and hitting ethers type conflicts, add:

"overrides": {
  "ethers": "npm:@sentio/ethers@6.13.1-patch.4"
}

sentio.yaml Quick Reference

project: owner/project-name     # Required
host: prod                       # prod | test | staging | local

contracts:
  - chain: "1"                   # EVM: numeric IDs ("1", "56", "137", "42161")
    address: "0x..."
    name: "USDC"
  - chain: aptos_mainnet         # Move: aptos_mainnet, sui_mainnet, iota_mainnet
    address: "0x1"
  - chain: sui_mainnet
    address: "0xdee9..."
    name: "deepbook"

networkOverrides:                # Redirect chain ID to custom RPC
  - chain: '2390'
    host: "https://rpc.tac.build"

variables:                       # Runtime env vars
  - key: API_KEY
    value: xxx
    isSecret: true

debug: false
numWorkers: 1

Processor Patterns by Chain

Proxy contracts: Use the implementation contract's ABI while binding to the proxy address.

Ethereum / EVM

import { Counter, Gauge } from '@sentio/sdk'
import { EthChainId } from '@sentio/chain'
import { ERC20Processor } from '@sentio/sdk/eth/builtin'
// Or generated: import { MyContractProcessor } from './types/eth/mycontract.js'

const transfers = Counter.register('transfers')

ERC20Processor.bind({
  address: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48',
  network: EthChainId.ETHEREUM,
  startBlock: 6082465,
})
  .onEventTransfer(async (event, ctx) => {
    transfers.add(ctx, 1)
    ctx.eventLogger.emit('Transfer', {
      distinctId: event.args.from,
      from: event.args.from,
      to: event.args.to,
      amount: event.args.value.scaleDown(6),
    })
  })
  .onTimeInterval(async (block, ctx) => {}, 60, 240)

Handlers: onEvent*, onBlockInterval, onTimeInterval, onTransaction, onTrace, onCallXxx

Event Filtering

Filter events to only process matching ones (e.g., only mints):

const mintFilter = ERC20Processor.filters.Transfer(
  "0x0000000000000000000000000000000000000000", // from = null address (mint)
  null  // any recipient
);

ERC20Processor.bind({ address: TOKEN, network: NETWORK })
  .onEventTransfer(async (event, ctx) => {
    // only mint events reach here
  }, mintFilter);

Generic Event Handler

Catches any event from the contract:

.onEvent(async (event, ctx) => {
  // event.eventName to determine which event
});

Function Call Handler (onCallXxx)

Triggers on internal function calls (trace-based). Access args and return values:

MyContractProcessor.bind({ address: CONTRACT, network: NETWORK })
  .onCallDeposit(async (call, ctx) => {
    // call.args, call.returnValue, call.error
  });

GlobalProcessor: GlobalProcessor.bind({ network }).onBlockInterval(handler)

Aptos

import { AptosNetwork } from '@sentio/sdk/aptos'
import { coin } from '@sentio/sdk/aptos/builtin/0x1'

coin.bind({ network: AptosNetwork.MAIN_NET })
  .onEventWithdrawEvent(async (evt, ctx) => {
    ctx.meter.Counter('withdrawals').add(1)
    ctx.eventLogger.emit('Withdraw', {
      distinctId: evt.guid.account_address,
      amount: evt.data_decoded.amount,
    })
  })

Handlers: onEvent, onEntry, onTransaction, onTimeInterval, onVersionInterval

Resources: AptosResourcesProcessor.bind({ address }).onResourceChange(handler, typeString)

Sui

import { SuiNetwork, SuiObjectTypeProcessor } from '@sentio/sdk/sui'
import { pool } from './types/sui/deepbook.js'

pool.bind({ network: SuiNetwork.MAIN_NET })
  .onEventSwap(async (evt, ctx) => {
    ctx.meter.Counter('swaps').add(1)
  })

SuiObjectTypeProcessor.bind({ objectType: pool.Pool.type() })
  .onObjectChange((changes, ctx) => {
    ctx.meter.Counter('pool_updates').add(changes.length)
  })

Handlers: onEvent*, onEntryFunctionCall, onObjectChange, onTimeInterval

Note: Use startCheckpoint: 8500000n (BigInt) instead of startBlock for Sui.

Solana

SolanaGlobalProcessor.bind({
  name: 'my-program',
  instructionCoder: new Anchor.BorshInstructionCoder(idl),
}).onInstruction('transfer', async (instruction, ctx, accounts) => {
  ctx.meter.Counter('transfers').add(1)
})

Starknet

StarknetProcessor.bind({ address: '0x...', network: StarknetChainId.STARKNET_MAINNET })
  .onEvent('Transfer', async (events, ctx) => {
    ctx.meter.Counter('transfers').add(events.length)
  })

Factory Pattern (ProcessorTemplate)

For dynamically-created contracts (e.g., DEX pair factory):

import { UniswapV2PairProcessorTemplate } from "./types/eth/uniswapv2pair.js";
import { UniswapV2FactoryProcessor } from "./types/eth/uniswapv2factory.js";

// 1. Define template with handlers
const pairTemplate = new UniswapV2PairProcessorTemplate()
  .onEventSwap(async (event, ctx) => {
    ctx.meter.Counter("swap_volume").add(event.args.amount0Out);
  })
  .onEventSync(async (event, ctx) => {
    ctx.meter.Gauge("reserve0").record(event.args.reserve0);
  });

// 2. Bind factory and dynamically bind new pairs
UniswapV2FactoryProcessor.bind({
  address: FACTORY_ADDRESS,
  network: NETWORK,
})
  .onEventPairCreated(async (event, ctx) => {
    pairTemplate.bind(
      { address: event.args.pair, startBlock: ctx.blockNumber },
      ctx
    );
  });

Metrics & Events

CRITICAL — Metric Naming: Names MUST NOT end with reserved suffixes: _count, _sum, _avg, _min, _max, _last. These are appended automatically by Sentio. Error: COUNTER name "X" is invalid, cannot use [_count _sum _avg _min _max _last] as the suffix: invalid meta

❌ Counter.register('transfer_count')    → invalid suffix _count
❌ ctx.meter.Counter('pool_sum')         → invalid suffix _sum
✅ Counter.register('transfers')
✅ ctx.meter.Counter('pools_created')

// Global registration (recommended)
const counter = Counter.register('name', { unit: 'token' })
counter.add(ctx, value, { label: 'value' })

// Inline via context
ctx.meter.Counter('name').add(value, { label: 'value' })
ctx.meter.Gauge('name').record(value, { label: 'value' })

// Sparse gauge (high cardinality — many pools/tokens)
const vol = Gauge.register("vol", {
  sparse: true,
  aggregationConfig: {
    intervalInMinutes: [60],
    discardOrigin: true,  // only keep aggregated vol_count, vol_sum
  },
})

// Event logging
ctx.eventLogger.emit('EventName', {
  distinctId: address,     // Primary entity ID (used for user-level analytics)
  message: 'description',
  // ... arbitrary key-value attributes
  // IMPORTANT: Numeric attributes used as time series metrics must be number or BigDecimal.
  // Passing string/undefined/null for numeric fields causes "invalid time series data" errors.
})

// Exporter (export to external systems via webhook)
ctx.exporter.emit({ key: "value" })

Label cardinality warning: ~10,000 unique series limit per metric. NEVER use wallet addresses, tx hashes, or token IDs as labels. Use event logs or entities for high-cardinality data instead.

Store (Database) API

Define entities in schema.graphql, generated by sentio gen:

type AccountSnapshot @entity {
  id: ID!
  timestampMilli: BigInt!
  balance: BigInt!
}

import { AccountSnapshot } from "./schema/store.js"

await ctx.store.get(AccountSnapshot, id)
await ctx.store.upsert(new AccountSnapshot({ id, timestampMilli, balance }))
await ctx.store.list(AccountSnapshot, [])  // List all
await ctx.store.delete(AccountSnapshot, id)

Critical: Enable sequential execution when using store to prevent race conditions:

import { GLOBAL_CONFIG } from "@sentio/runtime"
GLOBAL_CONFIG.execution = { sequential: true }

See references/store-and-points.md for points system patterns.

Price Feeds

import { getPriceByType, token } from "@sentio/sdk/utils"

const info = await token.getERC20TokenInfo(EthChainId.ETHEREUM, tokenAddr)
const price = await getPriceByType(EthChainId.ETHEREUM, tokenAddr, ctx.timestamp) || 0
const usdValue = amount.scaleDown(info.decimal).multipliedBy(price)

See references/defi-patterns.md for caching patterns and DeFi examples.

Testing

import { TestProcessorServer, firstCounterValue } from '@sentio/sdk/testing'

const service = new TestProcessorServer(() => import('./processor.js'))
before(async () => { await service.start() })

// Ethereum
const resp = await service.eth.testLog(mockTransferLog('0x...', { from, to, value }))
assert.equal(firstCounterValue(resp.result, 'transfers'), 1n)

sentio test                              # All tests
sentio test --test-name-pattern="swap"   # Filter by name

Project Structure

my-project/
  sentio.yaml              # Project config
  schema.graphql           # Store entity definitions (optional)
  package.json             # @sentio/sdk + @sentio/cli deps
  tsconfig.json
  abis/{chain}/            # Contract ABIs
  src/
    processor.ts           # Main processor code
    processor.test.ts      # Tests
    types/                 # Auto-generated (sentio gen)
    schema/                # Auto-generated store entities
  dist/lib.js              # Bundled output (sentio build)

Best Practices

1. Use sequential: true when handlers share state via entity store
2. Do NOT use global variables for persistent state — use ctx.store
3. Use startBlock to skip irrelevant history and reduce backfill cost
4. Prefer Metrics over Logs/Entities for aggregated numerical data (lower cost)
5. Never use addresses/hashes as metric labels — ~10k series limit per metric
6. Use event filters (Processor.filters) to reduce unnecessary handler executions
7. Increase backfill intervals to the largest acceptable value for cost reduction
8. Use listIterator() instead of list() for large entity datasets
9. Use Promise.all for parallel contract calls and entity processing
10. Use BigDecimal and scaleDown() for precision — avoid floating point
11. Filter null addresses with isNullAddress() for mint/burn events
12. Skip self-transfers — if (from == to) return;

Common Mistakes