aid: fixed-format
name: Fixed Format
description: >-
  Fixed format (also known as fixed-width) is a data interchange approach where
  every field has a predefined column width and is space-padded as needed. It
  contrasts with delimiter-separated formats like CSV, and is widely used in
  legacy mainframe systems, banking files, healthcare claims, government
  filings, and Unix system files such as /etc/passwd. While not an API in the
  REST sense, fixed-format files remain a critical data exchange medium that
  modern APIs and ETL pipelines must read and write.
type: Index
image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
url: >-
  https://raw.githubusercontent.com/api-evangelist/fixed-format/refs/heads/main/apis.yml
created: '2025-01-01'
modified: '2026-04-28'
specificationVersion: '0.19'
tags:
  - Data Exchange
  - Data Formats
  - File Formats
  - Fixed Format
  - Fixed Width
  - Flat Files
  - Legacy Systems
  - Mainframe
apis: []
common:
  - type: Reference
    url: https://en.wikipedia.org/wiki/Flat-file_database
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com