Fastest Growing SaaS Startups in the USA in 2025

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SaaS Startups in the USA

Introduction

In 2025, the era of SaaS Startups in the USA has entered hyper-growth mode. A wave of cloud-based innovators is reshaping how businesses operate - deploying AI, developer tools, HR platforms, and compliance engines that scale rapidly. These startups achieve meteoric success through capital efficiency, global reach, and razor-sharp product-market fit.

But what truly defines the fastest-growing SaaS Startups in the USA? These are companies that combine triple-digit growth, breakthrough funding, and fast-scaling teams - all while solving critical business problems. They span verticals from AI-powered code assistants to payroll platforms and data observability tools, often achieving $ 100 M+ ARR within years.

This feature showcases the top SaaS Startups in the USA that are dominating 2025’s tech headlines: explosive revenue, ambitious teams, and services that are rewriting the cloud playbook.

Top Fastest Growing SaaS Startups in the USA

1. Anthropic

  • Website: anthropic.com
  • Overview: Founded in 2021 and based in San Francisco, Anthropic is hitting a $3 billion annualized revenue run rate - a feat unmatched by legacy SaaS players. With 450+ staff, the company offers AI models (Claude) focused on code generation, enterprise workflows, and API integration. Their generative AI-as-a-service platform powers high-demand enterprise automation, making them arguably the fastest-growing SaaS enterprise on record.

2. Deel

  • Website: deel.com
  • Overview: Founded in 2019 in San Francisco, Deel now supports global payroll and compliance. With a team of ~6,000 and a $1 billion ARR, they're a standout among SaaS Startups in the USA. Their core services include international contractor payments, contractor classification, immigration tools, and benefits, offering a unified platform that enterprises use to hire remote talent worldwide.

3. Cribl

  • Website: cribl.io
  • Overview: Based in San Francisco and founded in 2018, Cribl employs ~800 and reported $100 million in revenue by 2023. Their SaaS platform empowers IT and security teams to manage data pipelines by routing, transforming, and analyzing logs and metrics from disparate sources, simplifying observability at enterprise scale.

4. Unqork

  • Website: unqork.com
  • Overview: A New York–York-headquartered, no-code SaaS provider founded in 2017. Unqork delivers visual PaaS solutions for finance, insurance, and government markets. The platform enables teams to build enterprise-grade applications with zero code. Having evaluated on digital health portals during COVID, it’s now scaling rapidly across regulated sectors.

5. Gigs

  • Website: gigs.com
  • Overview: With roots in YC and Ribbit Capital backing, Gigs is building an embedded mobile connectivity platform for developers and enterprises. Founded ~2021, they now have ~90 staff across the US and Europe. Their core service provides connectivity-as-a-service: issuing SIMs through a single API for mobile device fleets, a rapidly expanding B2B SaaS model.

6. Notion

  • Website: notion.so
  • Overview: The San Francisco–based productivity SaaS, founded in 2013, saw ~36% ARR growth in 2023 and continues scaling fast globally. With a user base spanning millions, Notion offers modular note-taking, wikis, project management, and APIs, becoming a favorite among remote-first enterprises and individual professionals alike.

7. RFPIO (Responsive)

  • Website: responsive.io
  • Overview: Founded in 2015 in Oregon, RFPIO (now Responsive) has 500 employees and over 150,000 users. Their SaaS platform automates RFP creation, streamlines collaboration, and provides analytics, helping companies respond faster and win more contracts.

Why These SaaS Startups in the USA Are Scaling So Fast

These seven companies reflect key growth drivers for the fastest-growing SaaS Startups in the USA:

  1. High-Traction Markets: AI enterprise software (Anthropic), remote HR/payroll (Deel), and data observability remain red-hot.
  2. Substantial TAMs: Platforms like Unqork and Cribl serve regulated and enterprise customers with high willingness to pay.
  3. Funding Momentum: Each startup has secured significant venture backing or revenue validation. Anthropic ($3B ARR), Deel ($1B ARR), RFPIO rapid growth, etc.
  4. Global Adoption: Rapid international expansion, APAC teams, data centre presence, multi-region customers, built into growth strategy.
  5. Strong Platforms: Developer tools (Notion, Gigs) and no-code platforms (Unqork) offer high network effects and user stickiness.

Choosing Among SaaS Startups in the USA

As you survey high-growth SaaS Startups in the USA, consider:

  1. Scale vs Focus: Anthropic and Deel offer massive scale and budgets; RFPIO and Gigs may provide more ownership and growth in tighter teams.
  2. Tech Depth: Cribl and Unqork sell B2B platforms with complex technical stacks; if you thrive on developer-level engineering, they're exciting.
  3. Role Scope: Notion’s cross-functional setup vs Deel’s HR-centric product or Anthropic’s AI innovation - pick a context aligned with your expertise.
  4. Stage Growth: Are you looking for rocketship momentum (Anthropic, Deel) or scaling orgs with >$100M ARR (Cribl, Unqork)? Each path shapes your career differently.

Detailed Company Profiles (Extended)

Anthropic

  • Staff: 450+
  • HQ: San Francisco, CA
  • Core Services: Claude AI models for enterprise, code generation, workflow automation, API integration.
  • Strength: Achieved $3B run-rate ARR within ~4 years - considered "the fastest-growing SaaS company ever". They lead the new wave of AI-native SaaS.

Deel

  • Staff: ~6,000
  • HQ: San Francisco, CA
  • Core Services: Global payroll, contractor management, compliance, and benefits for cross-border teams.
  • Strength: With $1B ARR and 75% YOY revenue growth, Deel stands as a top SaaS Startup in the USA, powering remote workforce operations.

Cribl

  • Staff: ~800
  • HQ: San Francisco, CA
  • Core Services: Data pipeline management for logs, metrics, and observability - routing across SIEM, lakes, and analytics engines.
  • Strength: $100M revenue by 2023; chosen by CIOs for scalable infrastructure observability.

Unqork

  • Staff: ~500–800 (2019 estimate)
  • HQ: New York, NY
  • Core Services: No-code enterprise PaaS - rapid app development for finance, insurance, and government sectors.
  • Strength: Developed NYC COVID portals; valued at >$2B by Series C.

Gigs

  • Staff: ~90
  • HQ: San Francisco & Europe
  • Core Services: Connectivity-as-a-service platform - API-driven mobile operator provisioning and SIM issuance.
  • Strength: YC-backed, $ 100 M+ funding, and scaling connectivity tools for enterprise mobile services.

Notion

  • Staff: ~500–1,000
  • HQ: San Francisco, CA
  • Core Services: All-in-one workspace - notes, docs, project tracking, databases, and API integrations.
  • Strength: 36% ARR growth, global enterprise and SMB adoption.

RFPIO (Responsive)

  • Staff: 500
  • HQ: Beaverton, OR (plus Coimbatore, India)
  • Core Services: RFP and proposal management automation with collaboration tools and analytics.
  • Strength: Over 150,000 users, strong automation ROI, and triple-digit user growth.

Conclusion

These SaaS Startups in the USA define what “fastest-growing” means in 2025, rapid ARR expansion, tech-driven offerings, and a global footprint. Anthropic, Deel, and Cribl lead with platform power and market urgency, while Notion, Gigs, Unqork, and RFPIO add diversity in product types and career opportunities.

Each one embodies a different growth model and talent journey. Whether you're a developer, designer, HR guru, or sales leader, you’ll find your fit among these rising stars.

TechTalksToday curates expert company lineups. Want your SaaS startup to be featured in a future “Top Startups” article? Contact us and get your company spotlighted.

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