StackOne Competitive Intelligence & Landscape

StackOne (stackone.com) is a London-based company that provides integration infrastructure for AI agents, enabling them to connect, optimize, and secure external interactions to automate workflows across various business applications https://www.stackone.com/. The company's mission is to fuel innovation by ensuring AI agents can act across any application, addressing the complexity of integration that often hinders product innovation https://www.stackone.com/company/.

StackOne's core offerings include Platform Connect, which features over 420 pre-built AI agent integrations and a Connector Builder to create custom integrations for any API. It boasts 25,000+ pre-built actions across critical business functions such as HRIS/HCM, Recruiting, Customer Support, Sales & CRM, Accounting & Finance, and Marketing https://stackone.com/. The platform also includes Optimize Tool Discovery for semantic search across actions, a Falcon Engine for high-performance agentic execution, and Secure Defender for prompt injection guard and agent governance https://www.stackone.com/.

The company targets enterprises and developers building or using AI agents that need to interact with diverse software systems.

StackOne was founded by Guillaume Lebedel and his long-time collaborators, who collectively have over 10 years of experience in SaaS companies https://www.stackone.com/company/. In May 2025, StackOne raised $20 million in a Series A round led by GV (Google Ventures), bringing its total funding to $24 million. Other investors include Workday Ventures, XTX Ventures, Episode 1, and Playfair, along with angels from OpenAI, Deepmind, and Microsoft https://www.stackone.com/press-releases/stackone-raises-20m-series-a-led-by-gv-google-ventures-to-reinvent-saas-and-ai-agent-integrations.

StackOne is recognized for its "number one agentic semantic tool search," claiming 91.6% first-try accuracy on its S1 Search Bench https://www.stackone.com/press/. The company's services are designed to help AI agents perform actions reliably, bridging the gap between intelligent systems and the thousands of B2B SaaS applications that run modern businesses https://www.stackone.com/blog/bring-ai-agents-to-work-with-stackone/. Its robust infrastructure supports features like real-time data processing, multi-tenancy, audit logs, and regional data, catering to a wide range of use cases from employee onboarding to lead nurturing https://www.stackone.com/pricing/.

StackOne (stackone.com) offers a tiered pricing structure for its AI agent integration infrastructure, featuring a free Starter Plan, a Core Plan, and an Enterprise Plan. The Starter Plan provides free access to core service features, including up to 1,000 action calls per month. This plan includes all standard connectors (over 330 pre-built connectors with 21,000+ actions), managed authentication, multi-tenancy, and access to the MCP protocol and AI action SDK. It also allows for one custom connector via the Connector Builder, two projects for organization, and in-app chat support. Additional action calls beyond the free limit are priced at $0.003 per call.

The Core Plan and Enterprise Plan expand upon the Starter Plan's offerings. While specific pricing for these higher tiers is not publicly detailed, they introduce premium connectors, unlimited custom connectors built with the Connector Builder (which can be optimized for AI coding agents like Claude Code), and support for the A2A protocol. These plans also include enterprise-grade features such as SOC 2 certification and Service Level Agreements (SLAs), catering to businesses requiring more robust security and dedicated support.

StackOne's platform is built on its Falcon Engine, a next-generation agentic execution layer designed to optimize AI agent usage, reliability, and tool discovery. The platform offers multi-protocol support, enabling integrations via MCP servers, A2A protocol, and REST APIs, with the Falcon Engine handling protocol translation. Key features across plans include the Connector Builder for creating custom integrations, Tool Discovery with a lightweight retrieval model for high accuracy (91.6% first-try accuracy on S1 Search Bench), and Secure Defender for prompt injection guard and agent governance. The company frequently updates its offerings, with its managed MCP servers currently supporting 420 applications and 25,763 tools, expanding on the integrations available to users.

StackOne is actively expanding its team, signaling a strategic focus on enhancing its AI agent integration infrastructure. The company explicitly states that it is hiring across engineering, product, and go-to-market roles, with open positions listed on its careers page [https://www.stackone.com/company/]. This widespread hiring effort indicates a growth trajectory and a need to scale operations across all key business functions.

As StackOne evolves from an integration platform to essential B2B AI agent infrastructure, it is specifically seeking talented individuals to join its mission. A notable area of recruitment includes AI Engineers, even featuring what might be the world's first dedicated MCP Engineer role [https://www.stackone.com/blog/bring-ai-agents-to-work-with-stackone/]. This specialized hiring reflects StackOne's commitment to advancing its core technology and staying at the forefront of AI agent capabilities.

The company's hiring patterns suggest a strong emphasis on strengthening its technical backbone, particularly in areas related to AI agents, multi-protocol support (MCP), and general engineering. The call for AI Engineers and the pioneering MCP Engineer role highlight StackOne's strategic investment in developing robust and secure solutions for connecting AI agents to various external systems and optimizing their performance [https://stackone.com/].

StackOne has demonstrated robust financial growth and successful fundraising, securing a total of $24 million in funding. The company initially raised $3.6 million in a seed round during Q4 2023. This seed funding was led by Episode 1, with additional participation from investors such as Playfair Capital, Portfolio Ventures, Revenue Syndicate, Charlie Songhurst, Sequoia’s Scout fund, Blissgrowth, and angel investors including the co-founder of Github and executives from Google [stackone.com/company/, stackone.com/press/stackone-secures-3-6m-in-seed-funding-led-by-episode-1/].

Building on its initial success, StackOne announced a significant Series A funding round of $20 million in May 2025. This round was led by GV (Google Ventures), with contributions from Workday Ventures, XTX Ventures, and existing investors Episode 1 and Playfair. Angel investors from prominent AI companies like OpenAI, Deepmind, Microsoft, and Mulesoft also participated in this round [stackone.com/press/stackone-raises-20m-series-a-led-by-gv-google-ventures-to-reinvent-saas-and-ai-agent-integrations/, stackone.com/blog/stackone-secures-20m-series-a-led-by-gv-google-ventures-to-power-the-universal-integration-layer/]. This funding infusion brings the total capital raised by StackOne to $24 million, earmarking it for further development of its state-of-the-art tool-calling capabilities and a Universal Integration Layer for B2B SaaS and agents [stackone.com/press/stackone-raises-20m-series-a-led-by-gv-google-ventures-to-reinvent-saas-and-ai-agent-integrations/, stackone.com/blog/stackone-secures-20m-series-a-led-by-gv-google-ventures-to-power-the-universal-integration-layer/].

While specific revenue figures are not publicly disclosed, StackOne operates on a tiered pricing model that includes a free Starter plan for up to 1,000 action calls per month, with additional calls priced at $0.003 each. Core and Enterprise plans offer premium connectors and unlimited custom connectors, indicating a scalable revenue stream from its integration infrastructure for AI agents [stackone.com/pricing/, stackone.com/]. The company has also achieved significant operational milestones, including reaching 100 million API calls by Q3 2023 and expanding to over 100 integrations across six categories with customers on three continents by Q2 2024, signaling strong growth in its market presence and adoption [stackone.com/company/].

StackOne actively participates in and contributes to the AI and B2B software community through various events. The company maintains an "Events" page on its website, providing information about upcoming conferences, webinars, and meetups where the StackOne team will be present or speaking. These events offer opportunities for engagement and knowledge sharing within the industry.

Romain Sestier, Founder & CEO at StackOne, has been a notable speaker at industry events, including SaaStock London. At this conference, he delivered a keynote address focusing on the redefinition of software categories driven by AI-native architecture, targeting AI and B2B Software founders and senior teams. This highlights StackOne's leadership in discussing the evolving landscape of AI-driven software solutions.

StackOne also showcased its advancements at Cloudflare Connect 2025 in London. During this event, a demo illustrated an AI chat agent's capability to perform a complete employee onboarding process by retrieving applicant data, demonstrating how StackOne's infrastructure empowers AI agents in enterprise settings. The company also offers solutions for automating webinar and event follow-up, enabling AI agents to connect with webinar platforms, marketing automation, and CRMs to streamline registration, send reminders, track attendance, and segment contacts effectively.

Beyond external conferences, StackOne supports its partners with co-marketing initiatives, including joint case studies, blog posts, and campaigns designed to amplify reach. The company provides direct access to its engineering and partner team through shared Slack channels and offers dedicated technical resources, including onboarding and integration guides, indicating a collaborative approach to community and partner engagement.