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GSA7 min readUpdated June 7, 2026

SIN 541511: Web Based Marketing Guide for GSA MAS

A Refresh 32 guide to GSA MAS SIN 541511, Web Based Marketing, including category fit, NAICS/PSC context, max order, TDR/OLM status, and offer preparation notes.

Built for
Contractors mapping offerings, pricing support, catalog files, labor categories, or Add SIN modifications to official GSA MAS scope
By the end
Understand where SIN 541511 fits and what evidence to prepare before using it in an offer or modification.
Field guide

When SIN 541511 fits

Scope fit
A close-looking SIN can still be wrong if the subcategory, PSC, NAICS, or deliverable story points elsewhere.
Signal
541511 Services include, but are not limited to writing, modifying, testing, and supporting software to meet the needs of a particular customer. This can include website design and maintenance services, search engine development, email marketing, interactive marketing, web based advertising (including marketing and social media outlets), webcasting, video conferencing via the web, section 508 compliance, including captioning services, online media management; and related activities to web based services.^^^^Media will be provided in a format that is compatible with the ordering agency's software requirements. Continual website updates and maintenance may also be required. ^^^^NOTE: Any commissions received for media placement, conference planning, etc. will either (a) be returned to the ordering agency or (b) applied as a credit to the cost of the project, whichever the ordering agency prefers.
Response
Compare the buyer's requirement to the official SIN language before forcing the opportunity into a familiar lane.
Service proof
Service SINs can create labor-category, qualifications, worksite, and rate-support questions.
Signal
The SIN supports service work, labor categories, deliverables, and pricing support.
Response
Prepare labor category descriptions, service narratives, past performance, FCP Services Plus data, and pricing support.
Modification path
Adding a SIN can affect catalog files, service descriptions, pricing support, and buyer-facing records.
Signal
The contractor wants to add this SIN after award or adjust offerings tied to it.
Response
Use the Add SIN and Add Product/Labor Category modification pages to plan scope, price, and evidence changes.
Refresh 32

SIN 541511 quick facts

A compact view of the official SIN record from the user's Refresh 32 MAS offerings workbook.

Category
Professional Services
Marketing and Public Relations
NAICS
541511
NAICS codes associated with the SIN in the workbook.
PSC
DD01
Product Service Code mapped to the SIN.
Max order
$1,000,000
Ordering threshold for seeking additional price reductions.
Part 1

What SIN 541511 covers

541511 Services include, but are not limited to writing, modifying, testing, and supporting software to meet the needs of a particular customer. This can include website design and maintenance services, search engine development, email marketing, interactive marketing, web based advertising (including marketing and social media outlets), webcasting, video conferencing via the web, section 508 compliance, including captioning services, online media management; and related activities to web based services.^^^^Media will be provided in a format that is compatible with the ordering agency's software requirements. Continual website updates and maintenance may also be required. ^^^^NOTE: Any commissions received for media placement, conference planning, etc. will either (a) be returned to the ordering agency or (b) applied as a credit to the cost of the project, whichever the ordering agency prefers.

The official record maps this SIN to NAICS 541511 and PSC DD01. Those codes are not the whole strategy, but they help explain how the offering is categorized for buyers and reviewers.

Part 2

How to prepare the offer story

For service-oriented SINs, keep the service description, labor categories, pricing support, and past-performance examples aligned. A reviewer should be able to see what work is being sold, who performs it, and why the rate story is defensible.

If the SIN is being added through eMod, write down what changes operationally: new scope, new pricing, new files, catalog impact, and who owns maintenance after approval.

Part 3

Buyer and SEO language to keep straight

Use the SIN number, title, category, and subcategory together: SIN 541511 - Web Based Marketing - Professional Services - Marketing and Public Relations. That combination helps a buyer understand the lane quickly and helps the page avoid becoming a vague keyword page.

When writing capability language, explain the actual deliverables and evidence. Do not make the SIN carry the whole message by itself.

Examples

What this looks like in practice

Real-world checkHow to test SIN 541511 before building files

Start with the official title and description: Web Based Marketing sits under Professional Services > Marketing and Public Relations. Then compare your actual commercial offering to that scope, not only to the NAICS code.

If the fit still looks strong, build the proof stack: offering description, pricing support, past performance or product support, and any SIN-specific files the current GSA instructions require.

  • Confirm scope language.
  • Check NAICS and PSC signals.
  • Match the pricing file to the offering type.
  • Keep the support package reviewer-friendly.

Frequently asked questions

Is SIN 541511 part of TDR?

The Refresh 32 workbook marks TDR as Y for this SIN. GSA states that TDR became mandatory across MAS SINs with Refresh 31, so contractors should still verify current contract reporting instructions in official GSA sources.

Can order-level materials be used with SIN 541511?

The workbook marks OLM as Y. OLM treatment should always be verified against the current MAS solicitation, mass modifications, and contract-specific instructions.

Should I pick a SIN only because the NAICS matches?

No. NAICS helps, but SIN selection should be based on the actual offering, official SIN description, category/subcategory, pricing files, and buyer acquisition path.