StreamingFast Substreams manifest reference

What is a Substreams Manifest?

The manifest is the high-level outline for a Substreams implementation. The manifest file is used for defining properties specific to the current implementation and identifying the dependencies between the inputs and outputs of modules.
This page provides a reference guide of all fields and values used in a Substreams manifest.

Specification Version

Excerpt pulled from the example Substreams manifest.
specVersion: v0.1.0
Simply use v0.1.0 for the specVersion field.


Excerpt pulled from the example Substreams manifest.
name: module_name_for_implementation
version: v0.5.0
doc: |
Documentation heading for the package.
More detailed docs for the package.

Package Name

The field is used to identify the package.
The field also infers the filename when the pack command is run using substreams.yaml as a flag for the Substreams package.
  • The name must match the following regular expression. ^([a-zA-Z][a-zA-Z0-9_]{0,63})$
  • The regular expression translates to the following rules.
    • 64 characters maximum
    • Separate words with _
    • Starts with a-z or A-Z and can contain numbers thereafter

Package Version

The package.version field identifies the package for the Substreams implementation.
Note: package.version must respect Semantic Versioning, version 2.0

Package URL

The package.url field identifies and helps users discover the source of the Substreams package.

Package Doc

The package.doc field is the documentation string of the package. The first line is a short description; longer documentation should follow a blank line.


The imports section references WASM code, compiled protobuf definitions, and module definitions.
Tip: Imported modules can be referred to using a key later in the modules section.
Excerpt pulled from the example Substreams manifest.
ethereum: substreams-ethereum-v1.0.0.spkg
tokens: ../eth-token/substreams.yaml
prices: ../eth-token/substreams.yaml
The value should be a pointer to a Substreams manifest or a Substreams package.
The filename can be absolute or relative or a remote path starting with http:// or https://.
Imports will differ across each blockchain. For example, Substreams implementations that target Ethereum will reference an appropriate spkg file created for that blockchain. Solana, and other blockchains, will reference a different spkg or resources specific to the target chain.


The protobuf section points to the Protocol Buffer definitions used by the modules in the Substreams implementation.
Excerpt pulled from the example Substreams manifest.
- google/protobuf/timestamp.proto
- pcs/v1/pcs.proto
- pcs/v1/database.proto
- ./proto
- ../../external-proto
The Substreams packager will load files in any of the listed importPaths.
Note: The imports section of the manifest will also affect which .proto files end up in the package.
They are packaged with the modules to help clients decode the incoming streams, but are not sent to the Substreams server in network requests.
Refer to standard protobuf documentation for more information about Protocol Buffers.


The binaries field specifies the WASM binary code to use when executing modules.
The modules[].binary field uses a default value of default.
Note: Defining the default binary is required when creating a Substreams manifest.
Excerpt pulled from the example Substreams manifest.
type: wasm/rust-v1
file: ./target/wasm32-unknown-unknown/release/my_package.wasm
type: wasm/rust-v1
file: ./snapshot_of_my_package.wasm
The binary used in the modules section of the manifest can be overridden by defining user-specified binaries through a name. Illustrated in the manifest excerpt above by the other binary.


The type of code and implied VM for execution.
Note: At there is only one VM available with a value of: wasm/rust-v1.


The path points to a locally compiled WASM module. Paths are absolute or relative to the directory the manifest is located in; typically the root of the Substreams implementation.
Tip: The WASM file referenced by the binary field will be picked up and packaged into an .spkg when invoking the pack and run commands through the Substreams CLI.


Excerpt pulled from the example Substreams manifest.
- name: events_extractor
kind: map
initialBlock: 5000000
binary: default # Implicit
- source: sf.ethereum.type.v2.Block
- store: myimport:prices
type: proto:my.types.v1.Events
- name: totals
kind: store
updatePolicy: add
valueType: int64
- source: sf.ethereum.type.v2.Block
- map: events_extractor


The identifier for the module, starting with a letter, followed by a maximum of 64 characters of [a-zA-Z0-9_]. The same rules apply to the field.
It is the reference identifier used on the command line and in inputs. Each package should have a unique name.
Note: modules[].name also corresponds to the name of the Rust function that will be invoked on the compiled WASM code upon execution. It is the same function that will be defined. #[substreams::handlers::map](orstore) in your Rust code.
Tip: When importing another package, all module names will be prefixed with the package's name and a colon. This prefixing ensures that there will be no name clashes across multiple imported packages and nearly any names can be safely used.


The initial block for the module is where Substreams is will begin processing data for a particular module. The runtime will simply never process blocks prior to the one for any given module.
If all the inputs have the same initialBlock the field can be omitted and its value will be inferred by its dependent inputs.
initialBlock becomes mandatory when inputs have different values.


There are two module types associated with modules[].kind as indicated below.
  • map
  • store


Valid only for kind: store.
Specifies the merge strategy for two contiguous partial stores produced by parallelized operations.
Possible values for modules[].updatePolicy are as follows.
  • set (last key wins merge strategy)
  • set_if_not_exists (first key wins merge strategy)
  • append (concatenates two keys' values)
  • add (sum the two keys' values)
  • min (min between two keys' values)
  • max (max between two keys' values)


Valid only for kind: store.
Specifies the data type of all keys in the store, and determines the WASM imports available to the module to write to the store.
Possible values for modules[].valueTypes are as follows.
  • bigfloat
  • bigint
  • int64
  • bytes
  • string


An identifier defined in the binaries section.
The modules[].binary module will execute using the code provided. This allows multiple WASM definitions for different modules enabling caching while iterating on the WASM code.


Excerpt pulled from the example Substreams manifest.
- source: sf.ethereum.type.v2.Block
- store: my_store
mode: deltas
- store: my_store # defaults to mode: get
- map: my_map
inputs is a list of input structures. For each object, one of three keys is required. The inputs key types are:
  • source,
  • store (also used to define mode keys),
  • and map.


Valid only for kind: map.
Excerpt pulled from the example Substreams manifest.
type: proto:eth.erc721.v1.Transfers
The value for type will always be prefixed with proto: followed by a definition specified in the protobuf definitions, and referenced in the protobuf section.