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moov-io/ach

Moov's mission is to give developers an easy way to create and integrate bank processing into their own software products. Our open source projects are each focused on solving a single responsibility in financial services and designed around performance, scalability, and ease of use.

ACH implements a reader, writer, and validator for Automated Clearing House (ACH) files following the Nacha standards. ACH is the primary method of electronic money movement throughout the United States. The HTTP server is available in a Docker image and the Go package github.com/moov-io/ach is available.

If you're looking for an event driven ACH engine for uploading/downloading files and operations we have built moov-io/achgateway and run it in production. Our article How and When to use the Moov ACH Library will help to generate ACH files for upload to your ODFI.

Table of contents

• Project status
• Usage
  • As an API
    • Docker (Config)
    • Google Cloud (Config)
    • HTTP API (Config)
    • Data persistence
  • As a Go module
  • As a command line tool
  • As an in-browser parser
• OpenAPI SDKs
• Learn about ACH
• FAQ
• Getting help
• Supported and tested platforms
• Contributing
• Related projects

Project status

Moov ACH is actively used in multiple production environments. Please star the project if you are interested in its progress. The project supports generating and parsing all Standard Entry Class (SEC) codes and validating files according to the Nacha standards. If you have layers above ACH to simplify tasks, perform business operations, or found bugs we would appreciate an issue or pull request. Thanks!

Usage

The ACH project implements an HTTP server and Go library for creating and modifying ACH files. There are client libraries available for both Go and Node/JavaScript. We also have an extensive list of examples of the reader and writer applied to various ACH transaction types.

Docker

We publish a public Docker image moov/ach from Docker Hub or use this repository. No configuration is required to serve on :8080 and metrics at :9090/metrics in Prometheus format.

Pull & start the Docker image:

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

List files stored in-memory:

curl localhost:8080/files

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

Create a file on the HTTP server:

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

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

Read the ACH file (in JSON form):

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

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

Google Cloud Run button

To get started in a hosted environment you can deploy this project to the Google Cloud Platform.

From your Google Cloud dashboard create a new project and call it:

moov-ach-demo

Click the button below to deploy this project to Google Cloud.

Note: If you get an error about the image being marked as "Do Not Trust" follow the below steps.

Error: You launched this custom Cloud Shell image as "Do not trust"

$ 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

This error occurs when some security settings on your account / cloud shell are locked down. To run ACH you need to trust the image, so in the top-right click to restart this image as Trusted.

Click to "Return to default"

Then you'll need to clone down and launch ACH. Pick option #3 to clone this project.

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

Start the ACH server inside the cloned repository.

go run ./cmd/serverr

Connect to the web preview (e.g. https://YOUR-ACH-APP-URL.a.run.app:8080/files)

---

In the cloud shell you should be prompted with:

Choose a project to deploy this application:

Using the arrow keys select:

moov-ach-demo

You'll then be prompted to choose a region, use the arrow keys to select the region closest to you and hit enter.

Choose a region to deploy this application:

Upon a successful build you will be given a URL where the API has been deployed:

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

From the cloud shell you need to cd into the ach folder:

cd ach

Now you can list files stored in-memory:

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

You should get this response:

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

Create a file on the server:

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

You should get this response:

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

Finally, read the contents of the file you've just posted:

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

You should get this response:

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

HTTP API

The package github.com/moov-io/ach/server offers an HTTP and JSON API for creating and editing files. If you're using Go the ach.File type can be used, otherwise you can send properly formatted JSON. We have an example JSON file, but each SEC type will generate different JSON.

Examples: Go | Ruby

• Create an ACH file for a payment and get the raw file

Configuration settings

Environmental Variable	Description	Default
ACH_FILE_TTL	Time to live (TTL) for *ach.File objects stored in the in-memory repository.	0 = No TTL / Never delete files (Example: 240m)
LOG_FORMAT	Format for logging lines to be written as.	Options: json, plain - Default: plain
HTTP_BIND_ADDRESS	Address for ACH to bind its HTTP server on. This overrides the command-line flag -http.addr.	Default: :8080
HTTP_ADMIN_BIND_ADDRESS	Address for ACH to bind its admin HTTP server on. This overrides the command-line flag -admin.addr.	Default: :9090
HTTPS_CERT_FILE	Filepath containing a certificate (or intermediate chain) to be served by the HTTP server. Requires all traffic be over secure HTTP.	Empty
HTTPS_KEY_FILE	Filepath of a private key matching the leaf certificate from HTTPS_CERT_FILE.	Empty

Data persistence

By design ACH does not persist (save) any data about the files, batches, or entry details created. The only storage occurs in memory of the process and upon restart ACH will have no files, batches, or data saved. Also, no in memory encryption of the data is performed.

Go library

This project uses Go Modules and Go v1.18 or newer. See Golang's install instructions for help in setting up Go. You can download the source code and we offer tagged and released versions as well. We highly recommend you use a tagged release for production.

# Pull down into the Go Module cache
$ go get -u github.com/moov-io/ach

# Show the documentation for the BatchHeader package
$ go doc github.com/moov-io/ach BatchHeader

The package github.com/moov-io/ach offers a Go-based ACH file reader and writer. To get started, check out a specific example:

Supported Standard Entry Class (SEC) codes

SEC Code	Description	Example	Read	Write
ACK	Acknowledgment Entry for CCD	Credit	ACK Read	ACK Write
ADV	Automated Accounting Advice	Prenote Debit	ADV Read	ADV Write
ARC	Accounts Receivable Entry	Debit	ARC Read	ARC Write
ATX	Acknowledgment Entry for CTX	Credit	ATX Read	ATX Write
BOC	Back Office Conversion	Debit	BOC Read	BOC Write
CCD	Corporate credit or debit	Debit	CCD Read	CCD Write
CIE	Customer-Initiated Entry	Credit	CIE Read	CIE Write
COR	Automated Notification of Change(NOC)	NOC	COR Read	COR Write
CTX	Corporate Trade Exchange	Debit	CTX Read	CTX Write
DNE	Death Notification Entry	DNE	DNE Read	DNE Write
ENR	Automatic Enrollment Entry	ENR	ENR Read	ENR Write
IAT	International ACH Transactions	Credit	IAT Read	IAT Write
MTE	Machine Transfer Entry	Credit	MTE Read	MTE Write
POP	Point of Purchase	Debit	POP Read	POP Write
POS	Point of Sale	Debit	POS Read	POS Write
PPD	Prearranged payment and deposits	Debit Credit	PPD Read	PPD Write
RCK	Represented Check Entries	Debit	RCK Read	RCK Write
SHR	Shared Network Entry	Debit	SHR Read	SHR Write
TEL	Telephone-Initiated Entry	Debit	TEL Read	TEL Write
TRC	Truncated Check Entry	Debit	TRC Read	TRC Write
TRX	Check Truncation Entries Exchange	Debit	TRX Read	TRX Write
WEB	Internet-initiated Entries	Credit	WEB Read	WEB Write
XCK	Destroyed Check Entry	Debit	XCK Read	XCK Write

Segment Files

SEC Code	Name	Example	Read	Write
IAT	International ACH Transactions	Credit	IAT Read	IAT Write
PPD	Prearranged payment and deposits	Debit Credit	PPD Read	PPD Write

Command line

On each release there's an achcli utility released. This tool can display ACH files in a human-readable format which is easier to read than their plaintext format. It also allows masking DFIAccountNumber values with the -mask flag.

Download the latest release for your computer

$ achcli test/testdata/ppd-debit.ach
Describing ACH file 'test/testdata/ppd-debit.ach'

  Origin     OriginName    Destination  DestinationName       FileCreationDate  FileCreationTime
  121042882  My Bank Name  231380104    Federal Reserve Bank  190624            0000

  BatchNumber  SECCode  ServiceClassCode  CompanyName      DiscretionaryData  Identification  EntryDescription  DescriptiveDate
  1            PPD      225 (Debits Only)  Name on Account                     121042882       REG.SALARY

    TransactionCode   RDFIIdentification  AccountNumber      Amount     Name                    TraceNumber      Category
    27 (Checking Debit)  23138010            12345678           100000000  Receiver Account Name   121042880000001

  ServiceClassCode  EntryAddendaCount  EntryHash  TotalDebits  TotalCredits  MACCode  ODFIIdentification  BatchNumber
  225 (Debits Only)  1                  23138010   100000000    0                      12104288            1

  BatchCount  BlockCount  EntryAddendaCount  TotalDebitAmount  TotalCreditAmount
  1           1           1                  100000000         0

In-browser ACH file parser

Using our in-browser utility, you can instantly convert ACH files into JSON. Either paste in ACH file content directly or choose a file from your local machine. This tool is particularly useful if you're handling sensitive PII or want perform some quick tests, as operations are fully client-side with nothing stored in memory.

SDKs

Below are some SDKs generated from the API documentation:

• Node SDK | GitHub

• TODO - OpenAPI Guide

Learn about ACH

• Official Nacha ACH Guide for Developers
• Intro to ACH
• Create an ACH File
• ACH File Structure
• Balanced Offset Files
• Merging Files

FAQ

Is there an in-browser tool for converting ACH files into JSON?

Yes! You can find our browser utility at http://oss.moov.io/ach/.

Is my data being saved somewhere?

No, we do not save any data related to files, batch, or entry details. All processing is done in-memory.

What ACH transaction types are supported?

We support generating and parsing all Standard Entry Class (SEC) codes.

Where can I find the official Nacha Operating Rules?

You can purchase the most recent Nacha Operating Rules and Guidelines resource directly from their webstore. Additionally, Nacha has published a free ACH guide for developers.

Getting help

If you have ACH-specific questions, NACHA (National Automated Clearing House Association) has their complete specification for all file formats and message types.

channel	info
Project Documentation	Our project documentation available online.
Twitter @moov	You can follow Moov.io's Twitter feed to get updates on our project(s). You can also tweet us questions or just share blogs or stories.
GitHub Issue	If you are able to reproduce a problem please open a GitHub Issue under the specific project that caused the error.
moov-io slack	Join our slack channel to have an interactive discussion about the development of the project.

Supported and tested platforms

• 64-bit Linux (Ubuntu, Debian), macOS, and Windows
• Raspberry Pi

Note: 32-bit platforms have known issues and are not supported.

Contributing

Yes please! Please review our Contributing guide and Code of Conduct to get started! Check out our issues for first time contributors for something to help out with.

This project uses Go Modules and Go v1.18 or newer. See Golang's install instructions for help setting up Go. You can download the source code and we offer tagged and released versions as well. We highly recommend you use a tagged release for production.

Releasing

To make a release of ach simply open a pull request with CHANGELOG.md and version.go updated with the next version number and details. You'll also need to push the tag (i.e. git push origin v1.0.0) to origin in order for CI to make the release.

Testing

We maintain a comprehensive suite of unit tests and recommend table-driven testing when a particular function warrants several very similar test cases. To run all test files in the current directory, use go test.

Fuzzing

We currently run fuzzing over ACH in the form of a Github Action. Please report crashes examples to oss@moov.io. Thanks!

Related projects

As part of Moov's initiative to offer open source fintech infrastructure, we have a large collection of active projects you may find useful:

• Moov Watchman offers search functions over numerous trade sanction lists from the United States and European Union.

• Moov Fed implements utility services for searching the United States Federal Reserve System such as ABA routing numbers, financial institution name lookup, and FedACH and Fedwire routing information.

• Moov Wire implements an interface to write files for the Fedwire Funds Service, a real-time gross settlement funds transfer system operated by the United States Federal Reserve Banks.

• Moov Image Cash Letter implements Image Cash Letter (ICL) files used for Check21, X.9 or check truncation files for exchange and remote deposit in the U.S.

• Moov Metro 2 provides a way to easily read, create, and validate Metro 2 format, which is used for consumer credit history reporting by the United States credit bureaus.

License

Apache License 2.0 - See LICENSE for details.