Top AI Agent Builders Leveraging Gemini, OpenAI And LangChain
Daria Pohrebniak
Marketing Director - Reverb
09.01.2025
This list compares the top AI agent builders working with Gemini, OpenAI and LangChain, from development firms to agent platforms and frameworks, with each company’s location and agent focus.
Teams aren’t asking for demos — they’re asking for dependable agentic systems that actually move the needle. The picks below focus on production results, clear paths from prototype to rollout, and the practical decisions that make or break deployments by top AI agent builders. You’ll see who actually ships — from open frameworks and no-code platforms to hands-on consultancies that plug into your roadmap.
Each option here fits a different buyer. Some shine as developer-first frameworks, others as ready-to-run platforms, and a few as hands-on consultancies you can tap when bandwidth is tight — a mix that helps you compare the best AI agent builders against your goals and constraints without guesswork.
AI Agent Builders At A Glance
Company
Location
Agent focus
1. Impekable
San Francisco, California
Design and development firm building AI agents with OpenAI and modern frameworks
2. AgentOps
San Francisco, California
Agent monitoring, debugging and guardrails (SDK and dashboard)
3. Langbase
Fully remote, U.S. incorporated
Serverless AI infrastructure with managed vector database, memory and a no/low-code studio
4. Sourcegraph
San Francisco HQ with a distributed global team
Code search and AI code assistance (Cody)
5. Sublayer
New York City, New York (hybrid/remote)
Ruby AI agent framework and AI code assistants
6. Harvey
San Francisco, with presence in New York
Legal-grade LLMs for drafting, review and research
7. Zapier
Fully remote, employees across 38+ countries
Workflow automation with natural-language actions and model-agnostic orchestration
8. Intercom
San Francisco (global HQ) and Dublin (EMEA HQ)
Fin AI customer service agent and Inbox Copilot
9. Relevance AI
Sydney, Australia and San Francisco, USA
Multi-agent platform with orchestration, templates and vector database
10. CrewAI
San Francisco, California (HQ), distributed team
Multi-agent orchestration framework and enterprise studio
Impekable blends Silicon Valley-grade product thinking with enterprise software engineering, then applies that rigor to AI agents. The team plans workflows end to end — from UX to cloud — so agents land with the right permissions, guardrails, and user experience. Delivery spans pilots and incremental scopes, and they’re comfortable engaging without long-term lock-ins.
When you need design-quality agents that users actually adopt, Impekable’s cross-functional approach pays off. They build with OpenAI APIs and modern frameworks, integrating agents into web or mobile products with clear acceptance criteria and measurable outcomes — a straight line from concept to production for AI agent development services.
Services and expertise: UI/UX design; web & mobile app development; enterprise SaaS; AI agent development services using OpenAI and modern frameworks
Location: San Francisco, California
Team size: ~50 experts
Portfolio: Google, Panasonic, Twilio; plus startups and Fortune 500s
AgentOps gives engineering teams the observability layer agents were missing — session replay, tool call traces, cost tracking, and safety guardrails. Think of it as flight instruments for autonomous workflows, helping you find brittle prompts, route failures, and tighten policies before incidents show up in production. The SDK and dashboard drop into existing stacks quickly, with month-to-month usage and proof-of-value projects standard.
Because it plays nicely with OpenAI agents, Microsoft Autogen, and dozens of frameworks, AgentOps often becomes the nerve center for multi-model deployments. If you’re evaluatingtop platforms to build AI agents, this is the one focused on reliability and runtime truth more than marketing gloss.
Services and expertise: SDK + dashboard for agent monitoring, debugging, and guardrails; consulting on safe enterprise rollouts
Location: San Francisco, California
Team size: 10 experts
Portfolio: Platform used by thousands of engineers; adopted or tested by global firms (logos include Microsoft, Google, Accenture, Deloitte, Fidelity)
Langbase packages the scaffolding teams usually spend months wiring — serverless infra, vector memory, prompt/version control, analytics — so developers can ship agents without babysitting servers. Its AI Studio and SDKs help you design “AI Pipes” with semantic memory and tool use, and it scales from solo devs to enterprise teams. The engagement is flexible — build in the hosted environment, then switch plans or scale usage without a contract hanging over you.
The platform supports 600+ LLMs and plugs into LangChain, making it friendly to your preferred model lineup and workflow style. If you’re benchmarking the best AI agent builder companies that blend collaboration features with production-ready infra, Langbase earns the shortlist.
Services and expertise: Serverless AI infra; managed vector DB and memory; AI Studio (no/low-code); TypeScript/REST SDKs; LangChain-friendly
Location: Fully remote, U.S. incorporated
Team size: 20 experts
Portfolio: 36,000+ developers; trusted by teams at Google, Intel, Zendesk, Klarna, Netlify, Sourcegraph and many startups
Sourcegraph pairs its precise code intelligence with Cody, an AI teammate that knows your entire repository. Developers ask questions in natural language and get answers grounded in the actual codebase, not hand-wavy suggestions. Deployments can be hosted or on-prem, with a clear focus on privacy, policy controls, and production uptime — and you can evaluate without long commitments.
If you’re mapping top companies building AI agents for engineering work, Cody stands out as a proven “agent for code” in the enterprise. It fits daily developer workflows, speaks multiple languages, and brings measurable time savings.
Services and expertise: Semantic code search, navigation, and AI code assistance (Cody) with enterprise controls and IDE integrations
Location: San Francisco HQ with a distributed global team
Team size: ~200 experts
Portfolio: Used by major tech and financial institutions; 4 of the top 6 U.S. banks; 7 of the top 10 tech giants; 15+ government agencies; widely reported productivity gains
Sublayer focuses on developer tools, offering an open-source Ruby agent framework plus opinionated products like Blueprints for AI-assisted coding. Teams can spin up targeted automations — from code refactoring to weekly progress summaries — and stitch them into existing pipelines with simple CLIs and templates. It’s pragmatic, lightweight, and easy to trial without vendor entanglements.
Engineering leaders who don’t want to immediately hire AI agent developers get a fast lane here: stand up a proof, keep control of your stack, and expand as wins accumulate. Sublayer’s emphasis on reproducibility and open patterns makes it a fit for dev-tools-first cultures.
Services and expertise: Ruby AI Agent Framework; AI code assistants (Blueprints); project-management augmentations; LLM integrations (OpenAI today, Gemini-ready)
Location: New York City, New York (hybrid/remote)
Team size: 10 experts
Portfolio: Open-source adoption with community projects; collaborations drawing on founders’ Adobe roots; pilots across tech firms; beneficiaries include Johns Hopkins University and MLB
Harvey tailors large language models for legal work — drafting, review, research, and cited answers tuned to a firm’s knowledge. The product defaults to restraint and provenance, surfacing “I don’t know” when the evidence isn’t there and respecting data boundaries. Firms can run pilots on tightly scoped use cases, expand by practice group, and avoid heavy contractual commitments early.
For corporate legal teams assessing the best AI agent builder for business, Harvey blends vertical expertise with enterprise security — and a track record of usage inside elite firms. It’s built for real matters, not toy demos.
Services and expertise: Legal-grade LLMs for drafting, review, research, and Q&A; integrations with firm knowledge and legal content providers
Location: San Francisco, with presence in New York; global deployments
Team size: 150 experts
Portfolio: Adopted or piloted by top law firms including Allen & Overy; alliances such as LexisNexis; growing footprint in Fortune 500 legal departments
Zapier gives agents hands — 7,000+ app integrations and a mature automation engine — so instructions can turn into actions across SaaS. With natural-language actions and a ChatGPT integration (via GPT Actions/MCP), an agent can draft a reply, create a ticket, schedule a meeting, and update a CRM record in a single flow. It’s quick to test and scale, with usage-based pricing and no long-term contracts required to validate value.
If your shortlist includes top platforms to build AI agents, Zapier is the action layer that closes the loop between conversation and execution. It reduces custom glue code and shortens the distance between a pilot and something your ops team can trust.
Services and expertise: Workflow automation; 7,000+ integrations; natural-language actions; orchestration with OpenAI and model-agnostic APIs
Location: Fully remote, employees across 38+ countries
Team size: ~800+ experts
Portfolio: 2M+ businesses; 69% of the Fortune 1000 have used Zapier; case studies span tech, finance, education, and non-profits
Intercom folds AI into the support stack companies already use — live chat, ticketing, knowledge base — with Fin handling a large share of routine questions. Fin only answers from trusted sources, hands conversations to humans when needed, and gives managers tight control over content and tone. You can trial Fin on a subset of traffic, tune guardrails, and scale without long-term commitments.
Among the best AI agent builder companies in customer service, Intercom stands out for connecting AI answers with human workflows under one roof. Support leaders get faster responses, cleaner escalations, and analytics tied to the same system agents already live in.
Services and expertise: Customer communications suite; Fin AI customer service agent; Inbox Copilot; knowledge base and omnichannel support
Location: San Francisco (global HQ) and Dublin (EMEA HQ), with offices in Chicago, Sydney, London
Team size: ~1,000 experts
Portfolio: 25,000+ businesses; reference stories include Anthropic, Amazon, monday.com, Atlassian, Activision with strong self-serve resolution rates
Relevance AI lets teams create “AI workforces” — multiple agents collaborating on sales, marketing, research, and support — all via no-code workflows. It bundles vector memory, orchestration, security, and a UI that non-technical users can navigate. You can start with text-to-agent templates, run controlled pilots, and expand without locking into a heavy SOW.
For operations leaders deciding whether to hire AI agent developers or empower business teams directly, Relevance makes a compelling case. It abstracts the plumbing while keeping room for custom APIs and enterprise deployment patterns.
Services and expertise: Multi-agent platform with vector DB, orchestration, templates, and enterprise security; integrations with major LLMs (OpenAI today, Gemini-ready)
Location: Sydney, Australia and San Francisco, USA
Team size: ~84 experts
Portfolio: January 2025 saw 40,000+ agents created; customers include Activision, Qualified, SafetyCulture; backed by a $24M Series B (Bessemer)
CrewAI popularized the “crew” model — role-based agents that collaborate, delegate, and validate each other’s work. It ships as an open-source framework plus an enterprise platform with visual builders and monitoring, so teams can start small and grow into managed features as needs scale. The company supports straightforward evaluations and pilots — no multi-year commitments just to get started.
An active open-source community helps top AI agent builders move faster, while the enterprise platform gives IT the oversight it needs. As a model-agnostic orchestrator, CrewAI naturally frames OpenAI vs Gemini for AI agents as a “use the right one per task” decision rather than a vendor bet.
Services and expertise: Multi-agent orchestration framework; enterprise studio; dashboards; works with OpenAI, Anthropic, and open models; LangChain-compatible
Location: San Francisco, California (HQ), distributed team
Team size: ~29 experts
Portfolio: Used across business workflows, QA, and analytics; highlighted in tutorials from large tech brands; >1M multi-agent runs; ~$3.2M revenue in 2025 from enterprise deals
Agent Platform Vs Custom Agent Development
There are two main ways to get an AI agent into production, and the companies above cover both.
Agent platforms and frameworks (such as CrewAI, Relevance AI, Langbase or Zapier) give you building blocks: model connections to OpenAI, Gemini and other providers, memory, tool calling, orchestration and monitoring. They are faster to start with and suit teams that have some in-house technical skill or want low-code options.
Custom agent development (from a firm such as Impekable) means a team designs and builds an agent around your data, systems and workflows, often using frameworks like LangChain under the hood. It suits complex, high-stakes or deeply integrated use cases.
Packaged agents inside products (such as Intercom’s Fin or Harvey for legal work) are ready-made agents for one job. They are quickest to deploy but less flexible.
What is the best framework for building AI agents?
It depends on the use case and your team. LangChain and LangGraph are widely used for single agents with tools and retrieval, CrewAI is popular for multi-agent workflows, and model providers such as OpenAI and Google offer their own agent SDKs. Choose based on the models you need, your programming language, observability options and how much control you want.
Is LangChain good for building AI agents?
Yes, LangChain is one of the most widely used frameworks for building agents, with large libraries of integrations for models, vector databases and tools. Its LangGraph library adds more control over multi-step and stateful agent workflows. Some teams find it adds complexity for simple tasks, so lighter SDKs can be a better fit for small projects.
Can you build an AI agent without code?
Yes. No-code and low-code platforms let you build agents with visual builders, templates and prebuilt connectors, and workflow tools like Zapier can add AI actions to existing automations. These options work well for common tasks such as research, support and data entry, while complex agents that need custom integrations or strict controls usually still need developers.
Making The Right AI Agent Choice
Pick by use case, not hype. If uptime and auditability rank first, AgentOps and Langbase give you the rails. For domain-specific outcomes — legal, support, or engineering — Harvey, Intercom, and Sourcegraph show strong proof. Agencies like Impekable round out the field when you want a partner who’s shipped products for the names everyone knows among the best AI agent builders.
Budget and risk posture matter too. No-code platforms help business teams move without waiting on roadmaps, while open-source frameworks keep control in engineering. Pilot small, measure real KPIs, and expand where adoption proves out. If you need extra lift — from prompt policy to production rollout — don’t hesitate to engage specialists for AI agent development services.
If you want to feature your AI agent builder on this list, email us or submit a form in the Top Choices section. After a thorough assessment, we’ll decide whether it’s a valuable addition.
