LinkedIn Message Ads: Complete Guide to Specs and Requirements

What Is a LinkedIn Message Ad

A LinkedIn Message Ad is a paid advertising format delivered through LinkedIn Messaging. It allows an advertiser to send a sponsored message directly to members who match the campaign targeting criteria.

A Message Ad appears as a message from a selected LinkedIn member rather than from a company page. It can include:

• A sender
• A subject line
• A personalized greeting
• Message text
• Up to three links in the message
• One Call-to-Action button
• An optional legal footer
• An optional desktop banner
• A LinkedIn Lead Gen Form

Message Ads are available on desktop and mobile devices.

Message Ads and Sponsored InMail: Is There a Difference?

Sponsored InMail was the earlier name commonly used for this LinkedIn advertising format. LinkedIn now refers to the format as Message Ads and includes it within the Sponsored Messaging category.

The terms are still used interchangeably in marketing materials and search queries. However, Message Ads should not be confused with regular LinkedIn InMail.

Regular InMail is a direct messaging feature available through some LinkedIn Premium and Sales Navigator plans. Message Ads are paid advertisements created and managed through LinkedIn Campaign Manager.

LinkedIn Sponsored Messaging includes two formats:

• Message Ads: one message with a single CTA button
• Conversation Ads: an interactive message with several response options and different conversation paths

This guide covers Message Ads.

How LinkedIn Message Ads Work

Message Ads are delivered to the LinkedIn inboxes of members selected through campaign targeting.

The advertiser chooses a sender, writes the subject and message, adds a CTA, and launches the campaign through Campaign Manager. LinkedIn then delivers the ad when eligible members are active on the platform.

Sponsored Messaging campaigns are charged on a cost-per-send basis. LinkedIn also controls how frequently members can receive Sponsored Messaging ads. Because of this limit, the same person is unlikely to receive the same ad repeatedly within a short period.

Message Ads support the following campaign objectives:

• Website visits
• Lead generation
• Website conversions

For lead generation campaigns, the CTA can open a LinkedIn Lead Gen Form instead of sending the member to an external landing page.

Within the European Union, Sponsored Messaging can only be delivered to members who have agreed to receive this type of advertising in their LinkedIn inbox.

LinkedIn Message Ad Components

A standard LinkedIn Message Ad consists of the following elements:

1. Sender: the LinkedIn member whose name and profile photo appear with the message.
2. Subject line: the text shown in the inbox before the message is opened.
3. Message text: the main advertising message.
4. Personalization macros: fields that can insert information from the recipient’s profile.
5. Clickable links: hyperlinks included inside the message.
6. CTA button: the primary action below the message.
7. Landing page URL: the destination connected to the CTA.
8. Custom footer: optional legal information, terms, or contact details.
9. Banner creative: an optional image displayed in some desktop views.
10. Lead Gen Form: an optional form for campaigns using the lead generation objective.

Message Ad Specifications

The maximum limits should not be treated as recommended lengths. A shorter message is usually easier to read, especially on mobile devices.

Sender Requirements

Every Message Ad must have a sender. The sender’s name and profile photo are displayed with the sponsored message.

Advertisers can select an approved sender or request permission from another LinkedIn member. Sender permission requests can normally be sent only to first-degree connections.

The invited member must approve the request before their profile can be used. The sender does not need to manage the campaign, but LinkedIn may give them viewer access to the associated ad account and Sponsored Messaging campaign.

Choose a sender who is relevant to the audience and offer. Examples include:

• A company founder for an executive event
• A sales director for a product demonstration
• A marketing director for an industry report
• A recruiter for a hiring campaign
• A subject matter expert for a webinar

A recognizable job title can make the message more credible. The sender’s LinkedIn profile should also be complete and up to date.

To test several senders, create separate ad variations. Each Message Ad variation can use only one sender.

Subject Line Requirements

The subject line can contain up to 60 characters, including spaces, punctuation, and personalization macros.

The final subject may be longer after a macro is replaced with profile information. This can cause truncation on some devices.

Keep the subject specific and easy to understand. It should explain why the recipient may want to open the message.

Examples:

• Invitation for B2B marketing leaders
• Join our LinkedIn Ads webinar
• A report for SaaS marketing teams
• Book your product demonstration
• %FIRSTNAME%, your webinar invitation

Avoid vague subjects such as:

• Important information
• Special offer
• Quick question
• Business opportunity
• You need to see this

A short subject gives the recipient more context before the text is truncated.

Message Text Requirements

The message text can contain up to 1,500 characters, including spaces and punctuation. LinkedIn also allows up to 10 emojis.

Available formatting options include:

• Bold text
• Italics
• Bulleted lists
• Hyperlinks

Keep the formatting simple. A Message Ad appears in a conversation interface, so it should be easier to read than a long promotional email.

LinkedIn recommends keeping the main message under approximately 500 characters. This is not a technical limit, but it is a useful starting point for mobile readability.

A practical message structure is:

1. Personalized greeting
2. Reason for contacting the recipient
3. Relevant problem or opportunity
4. Clear value of the offer
5. One next step

Do not begin with a long company description. Explain the relevance to the recipient before describing the advertiser.

Personalization Macros

LinkedIn macros automatically add information from the recipient’s profile to the subject line or message.

Available macros include:

• %FIRSTNAME%
• %LASTNAME%
• %COMPANYNAME%
• %JOBTITLE%
• %INDUSTRY%

Example:

Hi %FIRSTNAME%, we prepared a LinkedIn Ads benchmark for %INDUSTRY% marketing teams.

The recipient may see:

Hi Sarah, we prepared a LinkedIn Ads benchmark for software marketing teams.

Macros may not load when a member has disabled ad personalization or does not have the required profile information. LinkedIn then uses generic fallback text.

Examples of fallback values include:

• %FIRSTNAME%: LinkedIn Member
• %COMPANYNAME%: your company
• %JOBTITLE%: professional
• %INDUSTRY%: industry

Write every sentence so it still makes sense with the fallback value. Avoid using several macros in one sentence because missing or unusually long profile information can make the message difficult to read.

Always send a test message before activating the campaign.

Clickable Links

A Message Ad can contain up to three clickable links inside the message.

The linked text can contain up to 70 characters, including spaces and punctuation. Each link should clearly describe its destination.

Examples:

• View the complete industry report
• Check the webinar agenda
• See available demonstration times

Avoid generic anchor text such as “click here” when a more specific description is possible.

Links must begin with http:// or https://.

Some special characters can cause errors when used in URL parameters: angle brackets (< >), the hash sign (#), the percent sign (%), curly braces ({ }), and square brackets ([ ]).

Encode tracking parameters and test every link before launching the campaign.

Call-to-Action Button and Landing Page

A Message Ad includes one CTA button. The button text can contain up to 20 characters, including spaces and punctuation.

Common CTA options include:

• Learn More
• Register
• Download
• Request Demo
• Sign Up
• Book a Call
• Get the Report

The CTA should describe the action that happens after the click. Do not use “Download” if the destination is a page that requires several additional steps before the file becomes available.

The destination URL can contain up to 1,024 characters and must begin with http:// or https://.

The CTA can lead to:

• A website
• A landing page
• An event registration page
• A product demonstration page
• A LinkedIn Lead Gen Form

Use a Lead Gen Form when you want to collect contact information without sending the member away from LinkedIn.

Banner Creative Requirements

A banner is an optional image displayed beside the message in some desktop views.

Requirements:

• Dimensions: 300 × 250 px
• File type: JPG, PNG, or non-animated GIF
• Placement: desktop only
• Destination URL: required for clickable Message Ad banners

LinkedIn currently provides different file-size limits in its official help materials. The general Message Ads specification lists a maximum of 2 MB, while the dedicated banner guidance lists 40 KB.

Use a file of 40 KB or less to meet the stricter requirement.

The banner appears only when a member opens LinkedIn Messaging in the full desktop view. It does not appear on mobile devices or in the smaller conversation window.

If you do not upload a banner, LinkedIn may display an advertisement from another company in the available desktop slot.

Use the banner for:

• Brand recognition
• Product screenshots
• Event information
• A short supporting message
• A visual representation of the offer

Do not place essential campaign information only in the banner because many recipients will never see it.

Message Ads on Desktop and Mobile

The core message, subject, sender, links, and CTA can appear on both desktop and mobile devices.

The main difference is the banner:

• Desktop: the 300 × 250 px banner may appear in the right rail when the member uses the full Messaging page.
• Mobile: the banner is not displayed.
• Desktop conversation window: the banner may not appear when the message is opened in the smaller conversation interface.

The message must work without the banner. Include the main offer and CTA directly in the text.

Keep paragraphs short and check how the message looks on a narrow mobile screen. A message that appears concise on desktop may require significant scrolling on mobile.

LinkedIn Message Ad Best Practices

Choose a relevant sender

The sender should have a clear connection to the offer. A message from a relevant specialist is usually more credible than a message from an unrelated senior executive.

Explain the purpose immediately

The first lines should tell the recipient why they received the message and what they can gain from it.

Keep the message concise

Do not use the full 1,500-character limit unless the offer requires additional explanation. Start with a version under 500 characters and expand only when necessary.

Focus on one offer

Use one Message Ad for one primary action. Do not ask the recipient to download a report, register for an event, request a demonstration, and visit several product pages in the same message.

Use personalization carefully

A first-name macro can make the greeting more relevant. Several macros in one message can make the text look automated.

Match the CTA to the destination

The CTA text, message, and landing page should describe the same action and offer.

Optimize for mobile

Use short paragraphs, clear links, and a concise CTA. Do not rely on the desktop banner to explain the campaign.

Preview the message

Send a test message before activation. Check:

• Subject truncation
• Macro replacements
• Paragraph formatting
• Hyperlinks
• CTA button
• Landing page
• Mobile readability
• Banner quality

Test one variable at a time

Useful tests include:

• Sender
• Subject line
• Opening sentence
• Offer
• Message length
• CTA
• Landing page versus Lead Gen Form

Create separate ad variations when testing senders or messages.

Monitor results by stage

Evaluate more than the open rate. Review the complete path from delivery to conversion:

• Sends
• Opens
• Clicks
• Lead Gen Form submissions
• Website conversions
• Cost per lead
• Cost per conversion

A high open rate does not indicate success if recipients do not click or convert.

Message Ad Example

Sender:
Sarah Miller, Head of B2B Marketing

Subject:
LinkedIn Ads benchmarks for SaaS teams

Message:

Hi %FIRSTNAME%,

We analyzed how B2B SaaS companies use LinkedIn Ads to generate qualified leads.

The report covers creative formats, targeting approaches, CPL benchmarks, and common campaign mistakes.

You can download the complete report through the link below.

Best,
Sarah

CTA:
Get the Report

Destination:
LinkedIn Lead Gen Form or report landing page

This example uses one audience, one offer, and one action. It explains the value before asking the recipient to click.

When to Use LinkedIn Message Ads

Message Ads are suitable when the offer requires more explanation than a standard feed advertisement can provide.

Common use cases include:

• Webinar invitations
• Event registrations
• Product demonstrations
• Industry reports
• Research downloads
• Consultation requests
• Account-based marketing campaigns
• B2B lead generation

Message Ads are most useful when the audience is clearly defined and the offer is relevant to the recipient’s role, company, or industry.

They are less suitable for broad campaigns with a generic message. Because campaigns are charged per send and delivery frequency is controlled by LinkedIn, each message should have a clear audience and measurable objective.

Use Message Ads when direct communication supports the offer. Use feed formats when visual reach, repeated exposure, or broad awareness is the main priority.