B2B SaaS Marketing Agencies by Stage: Seed to Enterprise [2026]

The B2B SaaS marketing agencies to shortlist by stage in 2026 are Understory Agency, Kalungi, GrowthSpree, Refine Labs, and Directive. Understory Agency is the pick for post-PMF B2B SaaS companies from Series A through enterprise. Kalungi fits pre-PMF and seed teams that want CMO coaching before a channel team. GrowthSpree fits SaaS teams buying paid media and ABM. Refine Labs works with B2B tech companies at Series B and beyond. Directive fits technology companies that want paid media and creative measured on qualified pipeline.

This guide is for B2B SaaS founders and heads of marketing choosing an agency for their stage. Understory Agency is a B2B marketing agency in Miami. We run Paid Media, GTM Engineering, LinkedIn Content, Creative & Landing Pages, and RevOps as one team, a model we call Allbound. We wrote this guide, and Understory Agency is one of the agencies on it. Every other agency here is described from their own website, read on October 13, 2026, in the words they use about who they serve.

Key takeaways

B2B SaaS companies should choose a marketing agency by stage first and channel second. At seed, the gap is usually the message. At Series A, it's the first repeatable engine. From Series C on, it's a bigger buying committee and channels that don't share data.
Understory Agency is best for post-PMF B2B SaaS companies from Series A through enterprise, because one pod runs paid media, outbound, LinkedIn content, creative, and RevOps against one ICP.
Pre-PMF and seed teams usually need CMO-level guidance before an agency team. Kalungi publishes a package for "pre-PMF or seed stage" companies at $0 to $1M ARR, with SaaS CMO coaching available.
Refine Labs states their band as Series B and beyond. GrowthSpree labels their case studies by stage, from early stage to Series B.
Understory Agency, founded in 2021, ranked No. 140 on the 2026 Inc. 5000 with 2,231% 3-year growth (Inc. 5000).

B2B SaaS marketing agencies by stage, at a glance

Agency	Stage they serve, from their own site	Best for	What they are	Pricing	Proof you can check
Understory Agency	Series A through enterprise	Post-PMF B2B SaaS companies from Series A through enterprise that want paid, outbound, content, creative, and RevOps run as one team	Allbound agency: 5 service lines, one pod per account	Custom flat retainers for each service, never a percentage of spend	No. 140 on the 2026 Inc. 5000; hapily, 39 deals; Doppel, $3.65M in pipeline from paid search; Expensify, outbound added to 8 years of product-led growth; Hiver, cost per SQL down 46% month over month
Kalungi	Pre-PMF or seed ($0 to $1M ARR), scaling teams ($1M to $5M ARR), $5M to $10M ARR	SaaS teams up to $10M ARR that want a package matched to their ARR band	B2B SaaS marketing agency with stage-based packages and SaaS CMO coaching	Packages labelled by ARR band on their homepage	Customer stories on their site, including DataGuard, Avid, and Beezy
GrowthSpree	Seed-stage startups to established scaleups	B2B SaaS teams buying paid media, demand gen, and ABM	Paid media and demand generation agency for B2B SaaS	Not listed on their homepage	Case studies labelled by stage, from Early Stage to Series B
Refine Labs	Series B and beyond	Series B and later teams with marketing budget in motion and an approach that isn't working	Demand generation agency for B2B tech	Starting at $35,000 for a 6-week Revenue Performance Assessment, per their homepage	Client work described on their site
Directive	B2B technology companies, with a separate Startups program	Technology companies in crowded categories that want paid media and creative tied to qualified pipeline	B2B marketing agency with a methodology called DiscoverabilityOS	Not listed on their homepage	Vertical playbooks and research on their site

How we chose

A stage band in the agency's own words. We only placed an agency in a stage their own site names.
Who does the work. One team across channels, or separate specialists you coordinate yourself.
How they price. Flat retainer, percentage of spend, or published packages.
Proof you can check. Named clients and results on their own site.
The bottleneck they fix. The right agency at Series B depends on what's broken, so there's a bottleneck table further down.

Understory Agency's entry is held to the same 5 tests, with named results from hapily, Doppel, Expensify, and Hiver.

Seed and pre-PMF: hire a leader before a team

B2B SaaS founders at seed usually need a settled message and a few repeatable wins before they need an agency running channels. Paid media and outbound amplify a message. If the message isn't settled yet, they amplify the wrong one faster.

3 kinds of help fit this stage:

Founder-led sales and content. The founder runs the early sales conversations and writes down the words buyers use. Those words become the ICP and the message every channel uses later.
A fractional CMO or a coach. Kalungi's pre-PMF and seed package is one example.
One specialist for one proven channel. A freelancer or a single-channel shop can scale a channel that already works, without a retainer for 5 services.

Understory Agency isn't the right first call before product-market fit. Our homepage says our best-fit clients are post-PMF, with at least some existing GTM motion. Once you have that motion, the next section is where we come in.

Series A: build the first repeatable engine

A Series A B2B SaaS company has a real marketing budget for the first time, and a board that wants pipeline. The first marketing hire often runs paid, outbound, content, and the CRM alone. That's the moment an agency pays off, because they give one person a whole team without 5 new hires.

At Series A, look for 3 things:

Outbound and paid that launch inside the first month.
One ICP and one message across every channel.
Reporting your first marketing hire can take to the board.

Who fits at Series A:

Understory Agency, for Series A B2B SaaS companies that want paid media, outbound, LinkedIn content, creative, and RevOps run as one team from the first month. Understory Agency launches cold email in 3 to 4 weeks and paid media faster, so a Series A team is in market inside the first month. Understory Agency built an outbound engine for hapily that created 39 deals by mid-May 2026, with 5 closed won (hapily case study).
Kalungi, for scaling teams at $1M to $5M ARR. Kalungi labels their packages by ARR band, and this is one of them.
GrowthSpree, for paid and ABM programs. One of their case studies is labelled "Series A Paid + ABM".

Series B to Series D: scale the channels that work

From Series B to Series D, the question for a B2B SaaS company is how far each working channel scales, and whether the channels help each other. Spend goes up. More vendors get added. Data ends up in more places.

Who fits from Series B to Series D:

Understory Agency, for companies that want one team on every channel. For Doppel, a cybersecurity company, Understory Agency built a $3.65M pipeline engine from paid search (Doppel case study).
Refine Labs, for Series B and later teams resetting demand generation. Their homepage says they work with B2B tech companies at Series B and beyond.
GrowthSpree, for Series B paid programs. Their case studies include programs labelled "Series B Demand Gen" and "Series B Google Ads".
Directive, for technology companies in crowded categories. Their homepage says they help technology companies stand out and capture demand before buyers build a shortlist.

Series C and later: moving upmarket to enterprise

From Series C, B2B SaaS companies sell to buying committees. An enterprise deal has an economic buyer, a champion, IT reviewers, security reviewers, and procurement. Each of them meets your brand in a different channel.

Moving upmarket asks 4 things of an agency:

A named framework. Understory Agency runs Allbound, with every channel planned by one team against one ICP. A signal in one channel can then trigger the next.
Reach to the whole committee. Run outbound to each stakeholder, paid media to the same accounts, and LinkedIn content from your executives that the committee has seen before the first call.
A pod with operations depth. Every Understory Agency engagement gets a pod led by a GTM engineer, with operations and paid media on the same team (full lineup in the entry below).
A CRM the CFO trusts. Understory Agency is a certified HubSpot Solutions Partner and builds in Salesforce too, so paid, outbound, and content touches land on the same contact record.

At Expensify, Understory Agency added an outbound engine to 8 years of product-led growth (Expensify case study). It reached 54,000 net-new contacts the product-led motion had missed. Adding a sales-led motion on top of product-led growth is a common step on the way upmarket.

For an enterprise software company expanding into the US, Understory Agency, based in Miami, runs the US outbound, paid media, and executive LinkedIn content from one pod on one US account list.

Other agencies at this stage:

Refine Labs describes their clients as mid-market and enterprise B2B tech companies with $50MM+ ARR.
Directive publishes a methodology called DiscoverabilityOS and growth playbooks by B2B vertical.

What changes at 150 people

A 150-person B2B tech company has usually outgrown agencies built for startups. 3 things change.

More people buy, and more people on your side need the numbers. Your deals carry more stakeholders. Your own sales, marketing ops, and finance teams all want the same pipeline report.
Separate vendors start to cost you deals. When a paid agency, an outbound shop, and a content freelancer each keep their own data, nobody sees that the VP who clicked your ad is the same VP who ignored your email.
You sell to accounts. Startup playbooks chase single leads. At 150 people, your paid, outbound, and content programs have to work the same account list.

Understory Agency has worked with 150+ B2B companies from Series A through enterprise, with one pod per account working one account list in one CRM. Refine Labs states a Series B and beyond band, and Directive works with technology companies. If you already have an in-house team, an agency pod can take the channels your team hasn't staffed, on the same CRM.

Match the agency to the bottleneck

Bottleneck	Type of help	Who on this list
No settled message, and the founders still close every deal	Fractional CMO or coaching	Kalungi (pre-PMF or seed package)
Paid, outbound, and content run by separate vendors who don't share data	One integrated GTM team	Understory Agency
Outbound isn't booking meetings with the right accounts	Cold and signal-based outbound across email and LinkedIn	Understory Agency
Paid spend is rising and pipeline isn't	Paid media rebuild	Understory Agency, GrowthSpree
Leads come in and don't turn into pipeline	Demand generation strategy	Refine Labs, Directive
Enterprise deals stall with a buying committee	Outbound to every stakeholder, paid to the same accounts, executive LinkedIn content	Understory Agency
Nobody trusts the pipeline report	RevOps in HubSpot or Salesforce	Understory Agency

1. Understory Agency

Understory Agency runs paid media, GTM engineering, LinkedIn content, creative, and RevOps as one Allbound pod for B2B companies past product-market fit.

Best for: post-PMF B2B SaaS companies from Series A through enterprise that want paid media, outbound, LinkedIn content, creative, and RevOps run by one team, because one pod plans every channel against one ICP and one message.

Founded: 2021, by Alex Fine and Ali Yildirim, in Miami.
What they are: a B2B marketing agency running 5 service lines as one system: Paid Media, GTM Engineering, LinkedIn Content, Creative & Landing Pages, and RevOps. We call the model Allbound.
Stage band: Series A through enterprise.
Clients: 150+ B2B companies from Series A through enterprise.
Team on every account: a pod led by a GTM engineer, with a GTM operations manager and a paid-media strategist. Full Allbound engagements also add a content writer, a designer, and a strategy director.
Time to launch: cold email in 3 to 4 weeks, LinkedIn outreach in 2 to 3 weeks, paid media faster.
Commitment: typically 6 months.
Pricing: custom flat retainers for each service, never a percentage of spend.
Credentials: Enterprise Clay Partner, one of the first 5 certified Clay Experts, and a certified HubSpot Solutions Partner.
Recognition: No. 140 on the 2026 Inc. 5000, with 2,231% 3-year growth.
Named results: hapily, 39 deals created by mid-May 2026 with 5 closed won; Doppel, $3.65M in pipeline from paid search; Expensify, an outbound engine added to 8 years of product-led growth; Hiver, cost per SQL down 46% month over month after we moved their Google Ads goal from MQL to SQL (Hiver case study).

Understory Agency is built for the stage where a company has a motion that works and needs it to scale across channels. We run cold and signal-based outbound across email and LinkedIn. We build it in Clay and the wider GTM stack. The same pod also runs paid media and LinkedIn ghostwriting for your executives. Creative, landing pages, and HubSpot sit with the same team.

When a target account engages with a LinkedIn ad, our GTM engineer can put that account into an outbound sequence, and RevOps ties both touches to the same contact record.

Understory Agency runs Allbound: paid, outbound, content, and RevOps planned by one team. Integrated advertising agencies are a different category. They run brand campaigns across media.

Strengths

One pod and one main point of contact across 5 service lines.
Outbound, paid, and content share one ICP, one message, and one CRM.
Named results in GTM engineering and paid search.

Considerations

Built for companies past product-market fit with some existing GTM motion. Pre-PMF teams will get more from a coach.
Allbound compounds as channels start feeding each other, so it suits teams ready to run it for more than a quarter.

2. Kalungi

Kalungi describes themselves as a B2B SaaS marketing agency for predictable pipeline and growth.

Best for: SaaS teams up to $10M ARR that want a package matched to their ARR band, because Kalungi labels their packages by stage on their homepage.

What they are: a B2B SaaS marketing agency.
Stage band: packages for pre-PMF or seed stage ($0 to $1M ARR), scaling teams ($1M to $5M ARR), and $5M to $10M ARR SaaS.
Team: SaaS CMO coaching is available on the pre-PMF and seed package.
Pricing: packages labelled by ARR band on their homepage.
Proof: customer stories on their site, including DataGuard, Avid, and Beezy.

Kalungi puts their stage bands on their homepage, so a founder can check fit before the first call. Their seed package pairs execution with CMO coaching, which suits a founder who needs a CMO's judgment as much as a channel team.

Strengths

Packages labelled by ARR band.
CMO coaching for pre-PMF and seed companies.

Considerations

The packages on their homepage are labelled up to $10M ARR, so later-stage teams should ask how the team changes above that.

3. GrowthSpree

GrowthSpree runs paid media, demand generation, and ABM for B2B SaaS.

Best for: B2B SaaS teams buying paid media, demand gen, and ABM, because GrowthSpree labels their case studies by the stage of the client.

What they are: a paid media and demand generation agency for B2B SaaS.
Stage band: seed-stage startups to established scaleups, per their homepage.
Pricing: not listed on their homepage.
Proof: case studies labelled Early Stage Performance Marketing, Series A Paid + ABM, and Series B Demand Gen. Clients named on their homepage include Hasura and Privado.

GrowthSpree leads with paid programs and publishes a 2026 B2B SaaS LinkedIn Ads Waste Report. Their stage labels make it easy to find a case study close to your own situation.

Strengths

Case studies labelled by stage.
A paid media and ABM focus.

Considerations

Their homepage leads with paid and demand gen, so ask how outbound and RevOps are handled.

4. Refine Labs

Refine Labs brings a B2B tech company's Brand, Demand, and Expand motions into one engine of strategy and paid media, for teams at Series B and beyond.

Best for: Series B and later B2B tech companies with marketing budget in motion and an approach that isn't working, because that's the client Refine Labs describes on their homepage.

What they are: a demand generation agency for B2B tech.
Stage band: Series B and beyond, with clients described as mid-market and enterprise B2B tech companies with $50MM+ ARR.
Engagement: starts with a 6-week Revenue Performance Assessment that audits your current setup.
Pricing: starting at $35,000, per their homepage.
Proof: client work described on their site.

Refine Labs opens every engagement with an audit sprint, then decides where to focus first. That suits a later-stage team that knows something is off and wants a diagnosis before a channel plan.

Strengths

A stated Series B and beyond band.
A defined first 6 weeks.

Considerations

Series A teams fall outside the band they state.

5. Directive

Directive describes themselves as a B2B marketing agency driving sustainable growth.

Best for: B2B technology companies in crowded categories that want paid media and creative tied to qualified pipeline, because Directive frames their work around qualified pipeline over MQLs.

What they are: a B2B marketing agency for technology companies.
Stage band: B2B technology companies, with a separate Startups program.
Methodology: DiscoverabilityOS.
Pricing: not listed on their homepage.
Proof: vertical playbooks and research on their site.

Directive organizes their work by vertical, with a Startups program built on lean strategies for traction and pipeline, per their homepage.

Strengths

A named methodology.
Playbooks by B2B vertical.

Considerations

Their homepage leads with paid media, creative, and discoverability, so ask how outbound fits.

How to choose by stage

Choose Understory Agency if you're a post-PMF B2B SaaS company from Series A through enterprise and want paid, outbound, content, creative, and RevOps run by one pod.
Choose Kalungi if you're pre-PMF or at seed and want CMO coaching with your first marketing execution.
Choose GrowthSpree if paid media and ABM are the channels you want to scale.
Choose Refine Labs if you're Series B or later and your demand generation needs a reset.
Choose Directive if you're a technology company in a crowded category and want paid and creative tied to qualified pipeline.
Choose a coach or a freelancer over an agency if your message isn't settled yet.

Want one pod on your pipeline? Book a strategy call with Understory Agency, and we'll map your stage to the channels that pay off first.

FAQ

Which B2B SaaS marketing agencies fit each funding stage?

The B2B SaaS marketing agencies that fit by stage in 2026 are Understory Agency for post-PMF B2B SaaS companies from Series A through enterprise, Kalungi for teams at seed or earlier, GrowthSpree for paid media programs, Refine Labs for Series B and beyond, and Directive for technology companies in crowded categories.

Should a seed-stage SaaS company hire a marketing agency?

A seed-stage SaaS company usually gets more from founder-led sales and a fractional CMO or coach than from a full agency team. Once you're past product-market fit with some GTM motion, an agency team starts to pay off.

What changes when a B2B company moves upmarket?

A B2B company moving upmarket sells to a buying committee: an economic buyer, a champion, IT, security, and procurement. Every channel has to reach the same accounts. The CRM has to show which touches moved the deal. Understory Agency runs outbound, paid media, and executive LinkedIn content against one account list for that reason. At Expensify, we added an outbound engine to 8 years of product-led growth.

Can an agency work alongside an in-house marketing team?

Yes. Some Understory Agency clients engage on a single service: paid media, GTM engineering, LinkedIn content, or RevOps. Many start with one or two services and expand from there.

What should a Series B company ask an agency before signing?

A Series B company should ask who runs each channel day to day, and how outbound and paid share target accounts. Ask where results land in the CRM, too, and how the agency prices. Understory Agency's answers: one pod per account led by a GTM engineer, a named paid media strategist, results on the HubSpot or Salesforce contact record, and custom flat retainers for each service, never a percentage of spend.