NAICS 541511

Overview

The North American Industry Classification System (NAICS) is the federal standard for classifying business establishments to collect, analyze, and publish statistics about the U.S. economy. It is periodically revised; the current vintage is 2022. ¹
U.S. industry NAICS 541511 covers establishments primarily engaged in writing, modifying, testing, and supporting software to meet the needs of a particular customer. Federal buyers and data programs use this code to categorize custom application development and related client-specific software services. ²

What this NAICS covers

• Custom software design and development for a particular customer. ²
• Modification and enhancement of existing client applications to meet new requirements.
• Unit, integration, and system testing for customer-specific software builds.
• Ongoing support and maintenance of bespoke software solutions.
• Documentation and release packaging for tailored applications.
• Prototyping and proof-of-concept coding for client needs.

Related NAICS and PSC codes

Type	Code	Descriptor
NAICS	541512	Computer Systems Design Services (systems integration and design)
NAICS	511210	Software Publishers (packaged software publishing)
PSC	DA01	IT and Telecom – Business Application/Application Development Support Services (Labor)
PSC	DA10	IT and Telecom – Business Application/Application Development Software as a Service

Exclusions and boundary with related industries

• Packaged or mass-market software publishing is classified under NAICS 511210, not NAICS 541511. ³
• Planning and designing integrated computer systems (hardware/software/communications)—even when custom code is included as part of the service—is classified under NAICS 541512. ²

Frequently asked questions

• What is the official definition of NAICS 541511?
  The Census definition is: establishments primarily engaged in writing, modifying, testing, and supporting software to meet the needs of a particular customer. This code is used for custom application development and related client-specific software services. ²

• How does NAICS 541511 differ from NAICS 541512?
  NAICS 541511 is for custom programming designed for a specific customer. NAICS 541512 covers planning and design of integrated computer systems (hardware/software/communications), even when custom code is part of the systems effort. ²

• Which PSCs commonly align to custom application development under NAICS 541511?
  PSC DA01 (application development support services) and DA10 (application development SaaS/subscription) are frequently used. Their official descriptions cover analysis, design, coding, testing, and release packaging activities. ⁵

• What is the SBA small business size standard for NAICS 541511?
  SBA applies receipts-based size standards to each NAICS code. Verify the current dollar threshold for NAICS 541511 in SBA’s Table of Small Business Size Standards; contracting officers assign NAICS per 13 CFR 121. ⁴

• Is cloud-native or SaaS-related application development still within NAICS 541511?
  Yes. The defining feature is custom programming for a particular customer. Agencies often pair such efforts with PSCs like DA01 or DA10 when the work involves cloud application development or application development “as a service.” ⁶

Useful resources

• G2X — NAICS 541511 overview
• Census — NAICS 541511 (industry definition and cross-references). ²
• Census — Implementation of the 2022 NAICS (current vintage and transition timeline). ¹
• SBA — Table of Small Business Size Standards (check current threshold for NAICS 541511). ⁴
• GSA Acquisition.gov — Product and Service Code (PSC) Manual (see DA01/DA10). ⁵

References

1. U.S. Census Bureau — The Census Bureau’s Implementation of the 2022 NAICS (current vintage and program adoption). https://www.census.gov/library/reference/code-lists/naics/2022/implementation-timeline.html
2. U.S. Census Bureau — NAICS 2022: 541511 Custom Computer Programming Services (industry definition and cross-references). https://www.census.gov/naics/?input=541511&year=2022&details=541511
3. U.S. Census Bureau — NAICS 2022: 511210 Software Publishers (cross-references and boundary notes). https://www.census.gov/naics/?input=511210&year=2022&details=511210
4. U.S. Small Business Administration — Table of Small Business Size Standards (effective March 17, 2023). https://www.sba.gov/sites/default/files/2023-06/Table%20of%20Size%20Standards_Effective%20March%2017%2C%202023%20%282%29.pdf
5. General Services Administration — Product and Service Code (PSC) Manual, April 2025 (DA01/DA10 descriptions). https://www.acquisition.gov/sites/default/files/manual/PSC%20Manual%20April%202025.pdf
6. Acquisition.gov — AFARS Appendix HH Subpart: Cloud Computing (PSC mapping including DA01 and DA10). https://www.acquisition.gov/afars/appendix-hh-subpart-cloud-computing