ACH is an Apache-2.0 Go library and HTTP service from Moov that reads, writes, and validates Automated Clearing House (ACH) files against the Nacha standards, built for developers who need to generate or parse ACH files inside their own payment software.

What it is

ACH is an open-source implementation of a reader, writer, and validator for Automated Clearing House files. ACH is the primary method of electronic money movement throughout the United States, and Nacha defines the file format and rules that govern it. The project lives in the Go ecosystem and ships in three shapes from one codebase: an HTTP server, a Go module, and a command line tool. The HTTP server is published as a Docker image, the library is published as the Go package github.com/moov-io/ach, and client libraries exist for both Go and Node/JavaScript. It is part of the Moov family of projects, each of which is focused on solving a single responsibility in financial services.

The concrete problem it replaces is writing and maintaining an ACH file parser and generator by hand. Teams that move money need to produce fixed-width Nacha-formatted files for upload to their ODFI, and to read files that come back, with validation at every layer. ACH provides that reader, writer, and validator directly, and supports generating and parsing all Standard Entry Class (SEC) codes while validating files according to the Nacha standards. An extensive set of examples in the github.com/moov-io/ach/examples package shows the reader and writer applied to various ACH transaction types.

Key capabilities

• A reader, writer, and validator for Nacha-formatted ACH files, exposed through both the Go package and the HTTP API.
• Support for generating and parsing all Standard Entry Class (SEC) codes, with validation against the Nacha standards.
• A public Docker image, moov/ach, which serves on :8080 with no configuration required and exposes Prometheus-format metrics at :9090/metrics.
• A Go module at github.com/moov-io/ach and a Node/JavaScript client at moov-io/ach-node-sdk.
• OpenAPI-generated SDKs for calling the HTTP API from other languages.
• An in-browser ACH file parser and a command line tool for local use.
• Data persistence options for the HTTP server, plus configuration settings documented for Docker, Google Cloud Run, and the HTTP API.

Who uses it and how

• Payment teams that generate ACH files for upload to an ODFI, using the library or the HTTP API rather than hand-rolling a Nacha writer.
• Services that must parse and validate incoming ACH files before posting them to internal ledgers.
• Go shops that embed the module directly, and JavaScript teams that call the Node SDK or the HTTP API from a separate service.
• Operators running the container alongside other services, scraping :9090/metrics for Prometheus and routing traffic to :8080.
• Teams that need event-driven upload and download of ACH files with operations, which Moov addresses with the separate moov-io/achgateway project, described as running in production.

Getting started

Pull and run the published image with docker pull moov/ach:latest followed by docker run -p 8080:8080 -p 9090:9090 moov/ach:latest, or add the Go package github.com/moov-io/ach as a module dependency. A Deploy to Google Cloud Run button and configuration settings for Docker, Cloud Run, and the HTTP API are documented in the project docs.

How it compares

The facts provide no list of paid products that this project replaces, so no direct commercial comparison is drawn here. Within its own ecosystem, ACH is the file-level reader, writer, and validator, sitting underneath the event-driven moov-io/achgateway engine that handles uploading, downloading, and operations. No other tool in this registry entry is named as an equivalent alternative, so it stands alone here as the Nacha file handling implementation.

When to use it — and when not to

A self-hoster must run the container or embed the module, expose the HTTP API on :8080, and decide on data persistence for the server, since the README documents persistence as an explicit choice rather than a default. Teams that need a full event-driven ACH engine with upload and download operations should not expect this project to cover that alone; they should look at moov-io/achgateway as well. The project is actively used in production and the licence is clear at Apache-2.0, but the scope is deliberately narrow: it handles reading, writing, and validation of files, and layers that simplify tasks or perform business operations sit above it.

docker pull moov/ach:latest
docker run -p 8080:8080 -p 9090:9090 moov/ach:latest

curl localhost:8080/files

{"files":[],"error":null}

curl -X POST --data-binary "@./test/testdata/ppd-debit.ach" http://localhost:8080/files/create

{"id":"<YOUR-UNIQUE-FILE-ID>","error":null}

curl http://localhost:8080/files/<YOUR-UNIQUE-FILE-ID>

{"file":{"id":"<YOUR-UNIQUE-FILE-ID>","fileHeader":{"id":"","immediateDestination":"231380104","immediateOrigin":"121042882", ...

moov-ach-demo

$ cloudshell_open --repo_url "https://github.com/moov-io/ach" --page "shell" --git_branch "master"
Error: You launched this custom Cloud Shell image as "Do not trust".
In this mode, your credentials are not available and this experience
cannot deploy to Cloud Run. Start over and "Trust" the image.
Error: aborting due to untrusted cloud shell environment

cloudshell_open --repo_url "https://github.com/moov-io/ach" --page "shell" --git_branch "master"

go run ./cmd/serverr

Choose a project to deploy this application:

moov-ach-demo

Choose a region to deploy this application:

https://YOUR-ACH-APP-URL.a.run.app

cd ach

curl https://YOUR-ACH-APP-URL.a.run.app/files

{"files":[],"error":null}

curl -X POST --data-binary "@./test/testdata/ppd-debit.ach" https://YOUR-ACH-APP-URL.a.run.app/files/create

{"id":"<YOUR-UNIQUE-FILE-ID>","error":null}

curl https://YOUR-ACH-APP-URL.a.run.app/files/<YOUR-UNIQUE-FILE-ID>

{"file":{"id":"<YOUR-UNIQUE-FILE-ID>","fileHeader":{"id":"...","immediateDestination":"231380104","immediateOrigin":"121042882", ...