Helper for building ACH files in Ruby
Switch branches/tags
Nothing to show
Pull request Compare This branch is 162 commits behind jm81:master.
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.


ach is a Ruby helper for builder ACH files. In particular, it helps with field order and alignment, and adds padding lines to end of file.

This library has only been used in one production application and for very limited purposes. Please test thoroughly before using in a production environment.

See ACH::Builder for a similar Perl library


You should consult a copy of the ACH Rules for details on individual fields. You can probably obtain a copy from your bank.

# Create ACH file
ach =
trace_number = 0

# File Header
fh = ach.header
fh.immediate_destination = "000000000"
fh.immediate_destination_name = "BANK NAME"
fh.immediate_origin = "000000000"
fh.immediate_origin_name = "BANK NAME"

# Batch
batch =
bh = batch.header
bh.company_name = "Company Name"
bh.company_identification = "123456789"
bh.standard_entry_class_code = 'PPD'
bh.company_entry_description = "DESCRIPTION"
bh.company_descriptive_date =
bh.effective_entry_date = ( + 1)
bh.originating_dfi_identification = "00000000"
ach.batches << batch

# Detail Entry
ed =
ed.transaction_code = ACH::CHECKING_CREDIT
ed.routing_number = "000000000"
ed.account_number = "00000000000"
ed.amount = 100 # In cents
ed.individual_id_number = "Employee Name"
ed.individual_name = "Employee Name"
ed.originating_dfi_identification = '00000000'
batch.entries << ed
# ... Additional detail entries, possibly including *offsetting entry*, if needed.

# Insert trace numbers
batch.entries.each{ |entry| entry.trace_number = (trace_number += 1) }

output = ach.to_s"ach.txt", 'w') do |f|
  f.write output



Copyright (c) 2008-2009 Jared E Morgan, released under the MIT license