How it was ranked:10 startups compared. Each verdict is below.
Best AI Agent Startups: Top 10 Ranked. Sierra ranks first, with a Lister Score of 97.0.
Sierra leads AI agent startups globally for customer service agents at large enterprises, and Cognition's Devin is the best-funded software engineering agent. Harvey is the main choice for law firms, Replit lets anyone build an app by prompting an agent, and Genspark and Lindy are the easiest options for individuals who want an agent to handle everyday work.
Best AI Agent Startups in 2026, compared
RANK
ENTRY
BEST FOR
SCORE
FROM
1
SierraSierra's software is reported to be in use at nearly half of the Fortune 50.
Large enterprises automating customer service
97.0
Custom
2
CognitionCognition's run-rate revenue was reported at almost $900 million at the time of its September 2026 round.
Engineering teams handing off coding tasks
95.9
From $20 a month
3
HarveyHarvey's products are reported to be used by more than 100,000 lawyers across 1,300 organisations.
Large law firms
94.7
Custom
4
ReplitReplit said in March 2026 it was on track for $1 billion in run-rate revenue by the end of the year.
Teams and beginners wanting cloud-based development with integrated AI assistance
93.5
Free, £12/month (pro)
5
DecagonDecagon's enterprise customers include Avis Budget Group, Block and Deutsche Telekom.
Consumer brands with high support volumes
92.2
Custom
6
GleanGlean reported passing $200 million in annual recurring revenue in December 2025.
Large enterprise knowledge management
91.0
Custom
7
ParloaParloa has raised more than $560 million in total, according to reports on its Series D.
Enterprise customer service teams
89.7
–
8
GensparkGenspark's total funding reached about $545 million with the June 2026 extension, according to reports.
Individuals and small teams wanting a general AI agent
88.4
From $24.99 a month
9
LindyLindy offers new users $50 in free credits with no card required.
Solopreneurs and small business owners delegating entire email workflows to AI
87.1
$49.99/month
10
CrewAICrewAI's open-source framework has drawn tens of thousands of GitHub stars since its launch in October 2023.
Enterprise teams requiring governed multi-agent workflows
Sierra, co-founded by Bret Taylor and Clay Bavor and launched in 2024, builds AI agents that handle customer service conversations for large companies. It raised $950 million at a valuation of about $15 billion in May 2026, led by GV and Tiger Global.
Cognition, founded in 2023 in San Francisco, makes Devin, an AI agent that plans and writes code, fixes bugs and opens pull requests. It raised more than $2 billion in a Series E at a $48 billion valuation in September 2026, led by Andreessen Horowitz and Accel.
PROS
Free plan and low-cost entry tier
Fast revenue growth
CONS
Output still needs code review
Crowded coding agent market
Best for
Engineering teams handing off coding tasks
Where it falls short
Output still needs code review.
Pick something else if
you want fully autonomous coding without manual oversight.
Harvey, founded in 2022 in San Francisco, builds AI tools and agents for contract analysis, due diligence, compliance and litigation. It raised $550 million at a $15.5 billion valuation in September 2026, months after a $200 million round at $11 billion in March 2026.
PROS
Powerful custom LLM architecture
Deep integration with enterprise security
CONS
Restricted access with a waiting list
Best for
Large law firms
Where it falls short
Access is restricted to a waiting list, limiting immediate availability for new users.
Replit, founded in 2016, runs a browser-based coding platform whose Replit Agent builds and deploys working apps from plain-language instructions. It raised a $400 million Series D at a $9 billion valuation in March 2026, led by Georgian.
PROS
Instant setup with no local environment configuration needed
Built-in deployment capabilities and collaboration features for team projects
CONS
Performance and latency can be slower than local development environments
Limited offline functionality for web-based application
Best for
Teams and beginners wanting cloud-based development with integrated AI assistance
Where it falls short
The AI behavior is probabilistic and may occasionally make mistakes.
Decagon, founded in 2023 in San Francisco, builds AI agents that resolve customer support requests over chat, email and voice. It raised a $250 million Series D at a $4.5 billion valuation in January 2026, led by Coatue and Index Ventures.
Glean, founded in 2019 in Palo Alto, connects to a company's apps and documents so employees can search, get answers and run AI agents across them. It raised a $150 million Series F at a $7.2 billion valuation in June 2025, led by Wellington Management.
Parloa, founded in 2018 in Berlin, provides a platform for large companies to build and run voice and chat AI agents in their contact centres. It raised a $350 million Series D at a $3 billion valuation in January 2026, led by General Catalyst.
PROS
The AI tool continuously self-improves through its Performance Flywheel.
Parloa offers over fifty native integrations with no middleware required.
Genspark, from Palo Alto company MainFunc, offers a general-purpose AI agent that researches, writes, builds slides and makes calls for individuals and teams. In June 2026 it extended its Series B to $485 million at a $2.6 billion valuation.
PROS
Free tier to try it
Handles many task types in one place
CONS
Credit limits on cheaper plans
Young company
Best for
Individuals and small teams wanting a general AI agent
Where it falls short
Cheaper plans restrict usage through credit limits.
Lindy, founded by Flo Crivello in San Francisco, lets people build AI agents without code to manage email, schedule meetings, take notes and run sales and support workflows. Its backers include Battery Ventures, Accel and Menlo Ventures.
The Enterprise Agent Build & Runtime for your business
CrewAI, founded in 2023, makes an open-source framework and enterprise platform for building teams of AI agents that work together on business tasks. It raised an $18 million Series A led by Insight Partners in 2024.
PROS
CrewAI ensures every agent interaction is observable, compliant, and reversible through its Control Plane.
The AI tool intelligently guides complex operational agents using hundreds of thousands of workflow patterns.
Best for
Enterprise teams requiring governed multi-agent workflows
85.8
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Sierra ranks first on Lister. Sierra, co-founded by Bret Taylor and Clay Bavor and launched in 2024, builds AI agents that handle customer service conversations for large companies. It raised $950 million at a valuation of about $15 billion in May 2026, led by GV and Tiger Global.
