Indexer Comparison: Blockscout, Blockbook, and a Custom Indexer

Choosing the right indexer is one of the most consequential infrastructure decisions a wallet or blockchain application team will make. It determines how fast you sync, how much you pay to run, which chains you can support, and how much time your team spends on maintenance instead of product. This post compares three common options Blockscout, Blockbook, and building your own across the dimensions that matter most in production.

What Is a Blockchain Indexer?

A blockchain indexer is a service that reads raw block data from a node, parses and transforms it into queryable structures, and exposes an API so applications can retrieve balances, transaction history, token transfers, and UTXO sets without running full node queries. Wallets depend on indexers for every balance lookup and history fetch. The performance, reliability, and cost of the indexer directly shapes the user experience.

Full EVM Node
↓
PostgreSQL DB
↓
Elixir Indexer
↓
REST + GraphQL API
↓
Block Explorer UI

Bitcoin/EVM Node
↓
RocksDB (key-val)
↓
Go Indexer
↓
WebSocket + REST API
↓
No Built-in UI

Any Node (RPC)
↓
Custom DB Schema
↓
Custom Logic
↓
Custom API Layer
↓
Full Control

Architecture: Node -> Indexer -> Storage -> API

Blockscout

Blockscout is an open-source EVM block explorer written in Elixir. It connects to an EVM node via RPC, indexes all blocks, transactions, logs, and token transfers into a PostgreSQL database, and serves a full web-based block explorer UI alongside REST and GraphQL APIs. It is purpose-built for EVM chains Ethereum, Polygon, Gnosis Chain, and others and is the go-to choice when you need a public-facing explorer with rich search capabilities. The trade-off is resource appetite: PostgreSQL at scale demands significant storage and memory, the Elixir indexer requires careful tuning, and the full UI adds operational overhead. UTXO chains are not supported. For wallet backends that need lean, fast balance and history queries across multiple chains, Blockscout is often more than necessary.

Blockbook

Blockbook is an open-source indexer from the Trezor team, written in Go and backed by RocksDB a high-performance key-value store. It connects to a node via P2P or RPC, indexes address balances, UTXO sets, and transaction history, and exposes a WebSocket and REST API purpose-built for wallet backends. Blockbook natively supports both Bitcoin UTXO chains and EVM account-model chains, making it uniquely suited to multi-chain wallets. RocksDB's compaction and bloom filters deliver fast lookups with a fraction of the memory overhead of a relational database. There is no built-in UI, which is a feature rather than a limitation for teams who only need an API it keeps the footprint small and the focus sharp.

Blockscout:

Node RPC → Elixir Parser → PostgreSQL → REST/GQL

Blockbook:

Node P2P → Go Parser → RocksDB → WS/REST

Custom Indexer

Building your own indexer offers complete control: choose your database, define your schema, implement exactly the query patterns your application needs, and support any chain with an RPC endpoint. In practice, the cost is significant. Your team owns all of it initial development, reorg handling, gap detection, schema migrations, performance tuning, and ongoing maintenance as chain upgrades change data formats. Custom indexers make sense for highly specialised use cases where existing tools cannot meet requirements, or for teams with dedicated infrastructure engineers. For most wallet teams, it is an expensive way to replicate what Blockbook already provides.

Feature Comparison

Scored Evaluation

Scoring each option across five criteria that matter most for a production wallet backend:

Conclusion: Blockbook Is the Right Choice

Blockscout excels as a public-facing block explorer for EVM chains but that is a different problem. A custom indexer maximises flexibility but trades it directly for team bandwidth and operational risk. For wallet infrastructure teams evaluating all three options, Blockbook consistently comes out ahead:

• ✔ Native UTXO and account-model support one tool for Bitcoin and all EVM chains
• ✔ RocksDB delivers fast syncs and low-latency lookups at a fraction of PostgreSQL's resource cost
• ✔ WebSocket + REST API designed specifically for wallet query patterns (balances, UTXO, history)
• ✔ Maintained by the Trezor team with broad community adoption and well-understood operational characteristics
• ✔ No built-in UI keeps the footprint lean exactly right for a backend service
• ✔ Medium setup complexity beats both Blockscout's operational overhead and a custom build's development cost

Verdict: For multi-chain wallet backends that need reliable balance queries, UTXO support, fast sync, and low maintenance overhead, Blockbook is the clear winner. Start with Blockbook, layer your own caching and API gateway in front of it, and reserve custom indexer work only for gaps Blockbook genuinely cannot fill.

Which indexer is your team running in production, and what trade-offs have you hit? Drop your experience in the comments.