This guide covers some of the basics with regard to installing dependencies for the Fuel indexer service. However, note that this guide is meant to be a general overview for most platforms and by no means covers all platforms.

If you're having trouble with dependencies on your system, we recommend that you use docker.

To run the Fuel indexer, you'll need to install a few dependencies on your system:

  1. The Fuel toolchain
  2. A PostgreSQL server backend
  3. The wasm32-unknown-unknown rustup target
  4. wasm-snip, a utility for stripping symbols from WebAssembly binaries.

If you don't want to install a database directly onto your system, you can use Docker to run a database in an isolated container. You can install Docker by following its installation instructions.

For reference purposes, we provide a docker compose file that comes with a PostgreSQL server and a Fuel indexer service.

The Fuel toolchain

Please visit the Fuel installation guide to install the Fuel toolchain, which includes binaries for the Fuel indexer.


The Fuel indexer requires the use of a database. We currently support PostgreSQL.

IMPORTANT: Fuel Indexer users on most platforms don't need to explicitly install PostgreSQL software via a package manager. When starting the indexer service via forc index start simply pass the --embedded-database flag in order to have the indexer service download and start an embedded PostgreSQL instance via forc index postgres.

However note that this --embedded-database functionality can be a bit brittle or flaky on some platforms, so alternative methods of installing or using PostgreSQL are briefly mentioned below.


On macOS systems, you can install PostgreSQL through Homebrew. If it isn't present on your system, you can install it according to the instructions.

Once installed, you can add PostgreSQL to your system by running brew install postgresql.

Web Assembly (WASM)

Two additional cargo components will be required to build your indexers: wasm-snip and the wasm32-unknown-unknown target.

As of this writing, there is a small bug in newly built Fuel indexer WASM modules that produces a WASM runtime error due an errant upstream dependency. For now, you can use wasm-snip to remove the errant symbols from the WASM module, and prevent this issue from happening. An example can be found in the related script here.

Note that since wasm-snip strips Web Assembly related symbols, users will temporarily not be allowed to include other WASM-friendly crates (e.g., chrono) in their indexers.


To install the wasm-snip:

cargo install wasm-snip

wasm32 target

To install the wasm32-unknown-unknown target via rustup:

rustup target add wasm32-unknown-unknown

IMPORTANT: Users on Apple Silicon macOS systems may experience trouble when trying to build WASM modules due to its clang binary not supporting WASM targets. If encountered, you can install a binary with better support from Homebrew (brew install llvm) and instruct rustc to leverage it by setting the following environment variables:

  • AR=/opt/homebrew/opt/llvm/bin/llvm-ar
  • CC=/opt/homebrew/opt/llvm/bin/clang

Additionally, on some systems you need to explicitly link clang to llvm.

  • LIBCLANG_PATH="/opt/homebrew/opt/llvm/lib"
  • LDFLAGS="-L/opt/homebrew/opt/llvm/lib"
  • CPPFLAGS="-I/opt/homebrew/opt/llvm/include"