Quick Overview

Nebula is a cloud-based AI agent platform that builds what it calls an "AI workforce" from conversation (no code required). It gives you a 24/7 virtual computer, 1,000+ tool integrations, and built-in agents for browsing, coding, and media generation for $25 a month. If you want persistent memory, a self-hosted architecture, or an assistant that actually knows you rather than just executes tasks, there are stronger options. This guide covers 10 of them and who each one is actually for.

Top 10 Nebula Alternatives Shortlist

• Vellum: Personal AI assistant with persistent memory, credential isolation, and proactive reach-outs, built to know you rather than just run tasks.
• OpenClaw: Self-hosted open-source agent with a large community, no monthly platform fee, and skills that compound over time.
• Tensol: Managed AI employee for teams: dedicated VM per customer, zero data retention, built on OpenClaw's open-source core.
• Lindy: AI work assistant for inbox, meetings, and calendar, used by 400K+ professionals who want executive-assistant-level delegation.
• Gumloop: No-code AI automation framework for teams, $50M Series B, with a canvas-based workflow builder and enterprise-grade security.
• Hermes Agent: Self-improving open-source agent from Nous Research, built for engineering teams that want an agent that extends itself over time.
• n8n: Open-source AI workflow automation for technical teams with a large community, visual canvas plus full code flexibility.
• Manus: Autonomous cloud AI agent for complex multi-step tasks, now Meta-owned.
• Zapier: The dominant no-code automation platform, connecting 7,000+ apps through trigger-action workflows called Zaps.
• Make: Visual workflow automation with 1,500+ app connections, a generous free tier, and strong EU data residency options.

Why I Wrote This

I've spent a lot of time reviewing AI agent platforms, testing what they can actually do versus what the landing page implies. Nebula came up constantly in conversations this year. The virtual computer idea is clever, and the conversational setup is genuinely low-friction. But after using it, I kept hitting the same ceiling: it executes what you tell it, but it doesn't know you. No memory that builds over time. No proactive reach-outs. No identity. That gap matters if what you want is an AI that works with you, not just for you. These 10 alternatives represent the best of what's available if Nebula's model leaves you wanting more.

What Is an AI Agent Platform?

An AI agent platform is software that lets an AI take real actions in the world on your behalf, not just generate text. The best ones connect to the tools you already use, handle multi-step tasks without hand-holding, and can run in the background while you do other things. As of 2026, mature AI agent platforms handle email, calendar management, code writing and execution, browser automation, and file management. The differences that matter most between platforms are where your data lives, how credentials are handled, how much the agent remembers between sessions, and whether it surfaces things proactively or only acts when asked.

Key 2026 Trends in AI Agent Platforms

• Agentic AI adoption has crossed into production: a 2026 Gravitee survey of over 900 executives and practitioners found that 80.9% of technical teams have moved past the planning phase into active testing or full deployment [1]. Gartner forecasts 40% of enterprise applications will embed task-specific AI agents by end of 2026, up from less than 5% in 2025 [2].
• The market is shifting from rigid workflow-based automation toward dynamic agent architectures. Deloitte's 2026 agentic AI report finds that enterprises hitting the wall with agentic AI are those trying to automate existing processes without reimagining how work should actually be done: "leading organizations that are reimagining operations and managing agents as workers are finding success" [3].
• Credential security has become the defining blocker for enterprise AI agent adoption. Strata Identity research found that only 18% of security leaders are highly confident their current identity systems can manage agent identities, and 44% of teams still authenticate agents using static API keys [4]. Only 14.4% of organizations report all AI agents going live with full security and IT approval.
• Open-source AI agents have reached critical mass: n8n has built one of the largest communities in the automation space, OpenClaw has become the self-hosted personal agent benchmark, and Nous Research's Hermes Agent has developed a strong following among engineering teams that want self-improving systems.

Why Consider Nebula Alternatives?

• No persistent identity. Nebula doesn't build a profile of you that compounds over time. Each session starts without context about who you are or how you work.
• Cloud-only architecture. All processing and storage happens on Nebula's servers. There's no self-hosted option for teams with strict data residency requirements.
• Closed source. There's no public codebase to audit, fork, or extend on your own terms.
• Layered pricing. The platform costs $25/month, model usage is billed against Nebula Credits on top of that, and a 10% infrastructure surcharge applies to all model usage.
• No proactivity engine. Nebula executes tasks when you ask. It doesn't check in, notice what's overdue, or reach out on its own.
• Integration depth is narrower than it appears. 1,000+ integrations sounds large, but Zapier's 7,000+ covers most established business SaaS stacks more completely.
• No documented credential isolation model. There's no public information about how Nebula handles API keys and passwords at the architectural level.

Who Needs Nebula Alternatives?

• People who care about data ownership: If you want your files, credentials, and session history off someone else's server, you need a self-hosted or local-first platform.
• Developers and engineering teams: Teams that want to build, extend, and audit their own agents need an open-source or code-first platform.
• Enterprises with security requirements: Organizations that can't accept a shared cloud environment need documented security models, dedicated infrastructure, and RBAC.
• People who want an assistant that knows them: If you want an AI that remembers your working style, preferences, and ongoing projects across sessions, Nebula won't give you that.
• Businesses running on established SaaS stacks: If your team lives in Salesforce, HubSpot, or M365, a platform with 7,000+ integrations will fit more naturally than Nebula's 1,000+.

What Makes an Ideal Nebula Alternative?

• Persistent memory that builds across sessions, not a blank slate every time
• Transparent data handling: you know exactly where your data lives and who can access it
• Credential isolation: your API keys and passwords never reach the AI model
• Genuine real-world action capability beyond task execution: email, calendar, code, browser, phone
• Self-hosted or open-source option for teams that need full infrastructure control
• Pricing that reflects actual usage, not a platform fee plus per-token surcharges
• Proactive behavior: the agent surfaces relevant things without always waiting to be prompted
• Team and RBAC support for organizations with multiple users

Our Review Process

Each tool was evaluated on capability depth (what it can actually do in the world), privacy and security architecture (where data lives, how credentials are handled), ease of use (time to first useful task for a non-technical user), and pricing transparency (total cost of ownership, not just sticker price). No affiliate links. No sponsored placements. Vellum is ranked first; I work in this space and believe it's the right answer for most use cases, and I've been honest about its trade-offs too.

Best Nebula Alternatives (2026)

1. Vellum

Vellum is a personal AI assistant that lives in the cloud (or on your own machine) and actually knows who you are. It has its own email address, its own accounts, and a memory engine that builds a real picture of your work and preferences over time. Unlike Nebula, it reaches out when something matters, without being asked.

Score: 100

Standout strengths:

• Persistent memory across every session: it remembers your preferences, projects, and work context, and that knowledge compounds rather than resetting
• Credential isolation at the architecture level: your API keys and passwords live in a separate process and never reach the AI model
• Proactivity engine: Vellum checks in with itself hourly, notices what's unfinished or time-sensitive, and sends a message when it matters
• Own identity: it has its own email, its own accounts, and a personality you shape. It represents you; it doesn't impersonate you
• Broad real-world action capability: email, calendar, Slack, Telegram, phone calls, browser, code execution, food ordering, app building, and more
• Open source (MIT license) and self-hostable: the full codebase is auditable, and you can run it on your own infrastructure

Trade-offs:

• macOS is the most mature client today; Windows, mobile, and web clients are on the roadmap
• Skill setup for advanced integrations (phone calls, food ordering, etc.) requires one-time configuration

Pricing: Free download. Cloud hosting available.

Compared to Nebula: Nebula gives you a virtual computer and 1,000+ integrations but no persistent identity and no memory that compounds over time. Vellum builds a model of who you are and reaches out proactively; that's the difference between a capable task executor and an assistant that actually works with you. Credential isolation is documented at the architecture level on Vellum; Nebula has no equivalent published security model. And Vellum's open-source codebase means you can audit exactly what's happening with your data.

3. Tensol

Tensol deploys OpenClaw as a managed AI employee for businesses: each customer gets a dedicated isolated VM, automatic updates, and enterprise-grade security. It's YC-backed and built specifically for teams that want the power of OpenClaw without running their own infrastructure.

Score: 82

Standout strengths:

• Dedicated isolated VM per customer (stronger isolation than Nebula's shared virtual computer)
• Credentials injected at the network level, never reaching the AI model
• Zero data retention: Tensol doesn't train on your data
• RBAC with Admin, Engineer, and Viewer roles
• Automatic security patches and OpenClaw upgrades
• 40+ integrations including Slack, GitHub, Sentry, and HubSpot

Trade-offs:

• Pricing not publicly listed: requires enterprise sales conversation
• Team-oriented rather than individual: not ideal for solo users

Pricing: Pricing not listed publicly. Contact for enterprise pricing.

Compared to Nebula: Tensol is built for teams where Nebula is built for individuals. The credential isolation model is documented and architectural (network-level injection) versus Nebula's undocumented approach. If you're deploying an AI agent across a team with security requirements, Tensol has a clearer security story.

4. Lindy

Lindy is a personal AI work assistant focused on inbox, meetings, calendar, and follow-ups. It's used by 400K+ professionals and works through a web app, iMessage, and SMS delegation. Narrow, deep, and polished for the executive assistant use case.

Score: 79

Standout strengths:

• Inbox management that labels, triages, and drafts replies in your voice
• Joins Zoom calls, takes notes, extracts action items, and sends follow-ups automatically
• Prepares meeting briefs using your calendar and email context
• Proactive: notices what needs attention and prepares you without being asked
• Works from your phone via iMessage/SMS (no dashboard required)
• Connected to Gmail, Outlook, Google Calendar, Slack, HubSpot, Salesforce, Zoom, and more

Trade-offs:

• Narrow focus: strong for inbox and meetings, not a general-purpose coding or automation agent
• Cloud-only, no self-hosting option
• Pricing not listed publicly on the main marketing page

Pricing: Pricing not listed publicly. Subscription SaaS model.

Compared to Nebula: Lindy is deeper where Nebula is broader. If email and meeting management are your primary use cases, Lindy's 400K+ user base and focused feature set make it the stronger pick. For general-purpose task automation or coding agents, Nebula covers more ground.

5. Gumloop

Gumloop is a no-code AI automation framework for teams, backed by a $50M Series B led by Benchmark. It offers a canvas-based workflow builder, specialized agents for data analysis, support triage, CRM management, and meeting prep, delivered through Slack, Teams, Gmail, or WhatsApp.

Score: 75

Standout strengths:

• Canvas-based multi-agent workflow orchestration with visual debugging
• Recurring background agent runs on a schedule
• Enterprise security: VPC deployments, RBAC, SSO (Okta), audit logging, zero data retention agreements
• Bring your own API keys and proxy
• Multi-model support (Anthropic, OpenAI, Gemini, DeepSeek)
• Proven at scale: Gusto uses Gumloop to drive revenue and reduce churn

Trade-offs:

• Team/enterprise oriented; not designed for individual use
• Pricing requires enterprise sales conversation
• No personal AI assistant features: no persistent memory, no identity, no proactivity engine

Pricing: Pricing not listed publicly. Enterprise sales.

Compared to Nebula: Gumloop is a better fit for organizations than individuals. Its canvas-based builder gives technical teams more control over agent logic than Nebula's conversational interface. But it's missing personal AI features: no persistent identity, no proactivity, no memory that make an assistant feel like a working partner rather than an automation system.

6. Hermes Agent

Hermes Agent is a self-improving open-source AI agent from Nous Research. It's built for engineers and technical teams running agents on servers; not a consumer product. What distinguishes it is the self-improving architecture: Hermes can build new capabilities for itself through use, making it progressively more capable over time.

Score: 71

Standout strengths:

• Self-improving: builds new tools and capabilities through ongoing use
• Open source: full codebase is auditable and extensible
• Multiple execution backends
• Multi-model support
• No platform fee: open source and self-hosted

Trade-offs:

• High setup barrier: requires server infrastructure and technical knowledge
• No consumer-facing GUI: CLI and API first
• No 1,000+ integration library; integrations are built manually

Pricing: Open source (free). Requires own infrastructure and LLM API keys.

Compared to Nebula: Hermes is for engineers who want an agent they can extend and control at the deepest level. Nebula is for people who want to get started in minutes without touching infrastructure. These tools serve different audiences almost entirely.

7. n8n

n8n is an open-source AI workflow automation platform for technical teams with a large and active community. It combines a visual workflow canvas with full JavaScript and Python code flexibility, and it's self-hostable via Docker.

Score: 68

Standout strengths:

• Visual canvas plus full code: JavaScript or Python at any step in the workflow
• 500+ integrations with visual inspection of inputs and outputs at every step
• Multi-agent and RAG system support with MCP support
• Self-hosted via Docker, full source code on GitHub
• Native AI evaluation tools for testing workflows before they hit production
• Re-run single steps without replaying the entire workflow

Trade-offs:

• Technical setup required: not designed for non-technical users
• 500+ integrations is strong but narrower than Nebula's 1,000+ or Zapier's 7,000+
• No personal AI assistant features: no memory, no identity, no proactivity

Pricing: Free self-hosted. Cloud plans available. Enterprise pricing custom.

Compared to Nebula: n8n is for developers who want deep control over agent logic with code. Nebula is more accessible for non-technical users but less flexible for complex custom workflows. If you want to build in Python, test step-by-step, and self-host everything, n8n is a better fit.

8. Manus

Manus is an autonomous cloud AI agent built for complex, open-ended multi-step tasks. Built by Butterfly Effect (founded in China, now based in Singapore and acquired by Meta in early 2026), Manus handles research, data extraction, document creation, and code execution, all running asynchronously while you're offline.

Score: 64

Standout strengths:

• Strong performance on complex, long-horizon autonomous tasks
• Runs asynchronously: agent works while you're offline
• Browser automation, code execution, file handling in one system
• No setup friction for basic tasks

Trade-offs:

• Cloud-only: no self-hosting option, all data processed on Meta-operated servers
• No documented zero-data-retention or credential isolation model
• Meta acquisition raises data governance questions that teams with strict requirements should evaluate
• No persistent memory or personal identity features
• Pricing unclear post-acquisition

Pricing: Unclear post-Meta acquisition. Verify current pricing at manus.im before referencing.

Compared to Nebula: Manus is stronger for complex autonomous research and document tasks, but weaker on the integration library and team features. The Meta acquisition raises data privacy questions that Nebula, for all its cloud-only architecture, doesn't carry.

9. Zapier

Zapier is the dominant no-code automation platform, connecting 7,000+ apps through trigger-action workflows called Zaps. It recently added an AI agent layer called Zapier Central that monitors data and takes autonomous action. Founded in 2011, it's used by over 2.2 million businesses.

Score: 62

Standout strengths:

• 7,000+ app integrations (the largest library of any tool on this list)
• Established, stable platform with 15 years of reliability
• Zapier Central adds AI agent behavior on top of existing Zaps
• Tables and Interfaces for lightweight database and form use cases
• Free plan available (limited Zaps)

Trade-offs:

• Rigid workflow model: Zaps are trigger-action chains, not dynamic agent reasoning
• No virtual computer or coding agent capability
• No persistent memory or personal AI identity
• Cloud-only, no self-hosting
• Pricing adds up quickly as workflow complexity grows

Pricing: Free (5 Zaps). Starter ~$20/mo. Professional ~$50/mo. Team ~$70/mo. Enterprise: custom. (Verify current pricing at zapier.com/pricing before publish.)

Compared to Nebula: Zapier wins on integration breadth by a wide margin. If your automation needs map to connecting existing SaaS tools through established trigger-action logic, Zapier is more battle-tested. Nebula is better for conversational, exploratory task execution and for teams that want coding agents built in.

10. Make

Make (formerly Integromat) is a visual workflow automation platform with 1,500+ app connections. It offers a canvas-based scenario builder, strong EU data residency options, and a generous free tier. It's popular in Europe and among operations teams that prefer a visual-first automation tool with more control than Zapier.

Score: 58

Standout strengths:

• Visual scenario canvas with granular control over data mapping between steps
• 1,500+ app integrations with a generous free tier
• EU data residency options, a strong choice for GDPR-sensitive use cases
• Scheduling, filters, routers, and iterators for complex branching logic
• Lower cost than Zapier at comparable complexity

Trade-offs:

• Steeper learning curve than Zapier despite the visual interface
• No AI agent features comparable to Nebula or Zapier Central
• No persistent memory, identity, or proactivity
• Cloud-only

Pricing: Free plan (1,000 operations/month). Core: ~$9/mo. Pro: ~$16/mo. Teams: ~$29/mo. Enterprise: custom. (Verify at make.com/en/pricing before publish.)

Compared to Nebula: Make is a workflow automation tool, not an AI agent platform. If your use case is connecting apps and automating data flows, Make is cheaper and more visually controllable than Nebula. If you want AI-native agents that execute open-ended tasks, Nebula covers more ground.

Nebula Alternatives Comparison Table

<div style="overflow-x:auto;"><table style="border-collapse:collapse;width:100%;background:#ffffff;border-radius:8px;overflow:hidden;font-size:14px;"><thead><tr style="background:#3d3929;color:#ffffff;"><th style="padding:12px 16px;text-align:left;text-transform:uppercase;font-weight:600;color:#ffffff;">Tool</th><th style="padding:12px 16px;text-align:left;text-transform:uppercase;font-weight:600;color:#ffffff;">Best For</th><th style="padding:12px 16px;text-align:left;text-transform:uppercase;font-weight:600;color:#ffffff;">Architecture</th><th style="padding:12px 16px;text-align:left;text-transform:uppercase;font-weight:600;color:#ffffff;">Pricing</th><th style="padding:12px 16px;text-align:left;text-transform:uppercase;font-weight:600;color:#ffffff;">Open Source</th><th style="padding:12px 16px;text-align:left;text-transform:uppercase;font-weight:600;color:#ffffff;">Key Differentiator</th></tr></thead><tbody><tr style="background:#e8f5e9;"><td style="padding:10px 16px;border:1px solid #e5e2dc;color:#2e7d32;font-weight:600;">Vellum</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Personal AI assistant with identity and memory</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Cloud or self-hosted</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Free + cloud hosting</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Yes (MIT)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Persistent memory, credential isolation, proactive reach-outs</td></tr><tr style="background:#f9f8f6;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">OpenClaw</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Self-hosted personal AI with community skills</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Self-hosted</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Free (API costs only)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Yes</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">No platform fee, self-improving skills</td></tr><tr style="background:#ffffff;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">Tensol</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Managed AI employee for teams</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Dedicated VM (cloud)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Enterprise (unlisted)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Built on OpenClaw</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Isolated VM, network-level credential injection</td></tr><tr style="background:#f9f8f6;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">Lindy</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Inbox, meetings, and calendar management</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Cloud</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Subscription (unlisted)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">No</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">400K+ users, iMessage/SMS delegation</td></tr><tr style="background:#ffffff;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">Gumloop</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Team AI automation with enterprise security</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Cloud (VPC option)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Enterprise (unlisted)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">No</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Canvas orchestration, VPC, audit logging, $50M Series B</td></tr><tr style="background:#f9f8f6;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">Hermes Agent</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Engineering teams who want self-improving agents</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Self-hosted (server)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Free (API costs only)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Yes</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Self-improving architecture, six execution backends</td></tr><tr style="background:#ffffff;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">n8n</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Developers building custom AI workflows</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Self-hosted or cloud</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Free self-hosted</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Yes</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Large open-source community, code + visual canvas, MCP support</td></tr><tr style="background:#f9f8f6;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">Manus</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Complex autonomous research and document tasks</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Cloud (Meta-owned)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Unclear post-acquisition</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">No</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Strong long-horizon task performance</td></tr><tr style="background:#ffffff;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">Zapier</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Businesses with large existing SaaS stacks</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Cloud</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Free (limited); from ~$20/mo</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">No</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">7,000+ integrations, 15-year track record</td></tr><tr style="background:#f9f8f6;"><td style="padding:10px 16px;border:1px solid #e5e2dc;">Make</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">GDPR-sensitive teams wanting visual automation</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Cloud (EU residency)</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">Free (1K ops); from ~$9/mo</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">No</td><td style="padding:10px 16px;border:1px solid #e5e2dc;">EU data residency, visual canvas, lower cost than Zapier</td></tr></tbody></table></div>

Why Vellum Stands Out

Nebula is a capable platform. A 24/7 virtual computer with 1,000+ integrations and a conversational setup flow is a real product with real value. The limitation is what it doesn't carry between sessions.

The two things Nebula can't give you: an identity and a memory. When you come back tomorrow, Nebula doesn't know who you were yesterday. That's fine for one-shot task automation. It matters when you want an assistant that builds a working model of you over time: how you communicate, what you care about, what's overdue, what needs your attention before you even think to ask.

Vellum's architecture is built around that compound value. Memory is structured across sessions with source attribution so it knows why it remembers something, not just that it does. The proactivity engine checks in hourly and reaches out when something matters, no prompting required. And credentials live in a separate process that the AI model never touches, which is a documented architectural guarantee rather than a hope.

On the specific comparisons that matter for this category:

Vellum vs Tensol: Tensol is the right call for teams that need a managed deployment with dedicated infrastructure. Vellum is the right call for individuals and small teams that want persistent identity and memory on top of strong security.

Vellum vs OpenClaw: OpenClaw is a strong open-source alternative with no platform fee. Vellum adds managed cloud hosting, a structured memory engine, and a proactivity system that OpenClaw doesn't have out of the box.

Vellum vs Lindy: Lindy is excellent at inbox and meeting management. Vellum covers that and also handles phone calls, app building, food ordering, code execution, and more, with an identity that carries across all of it.

Vellum vs Zapier: Zapier wins on integration count. Vellum wins on everything that makes an assistant feel like a working partner rather than a pipe between apps.

Get started with Vellum free →

FAQs

What is the best alternative to Nebula?

Vellum is the best alternative for most people. It offers persistent memory, credential isolation, proactive reach-outs, and an open-source architecture, covering everything Nebula's virtual computer model skips. For teams with dedicated infrastructure needs, Tensol is the strongest enterprise option.

Is Nebula free?

Nebula has a free plan for basic exploration. The full platform (including the 24/7 virtual computer) costs $25/month. AI model usage is billed separately against Nebula Credits on top of that, with a 10% infrastructure surcharge. Total costs depend on how heavily you use the AI models.

Can I self-host an alternative to Nebula?

Yes. OpenClaw and n8n are both open-source and self-hostable: OpenClaw on your local machine or server, n8n via Docker. Vellum also supports self-hosting for teams that want full infrastructure control.

What is the most secure alternative to Nebula?

Vellum and Tensol have the strongest documented security models. Vellum's credential isolation keeps API keys and passwords in a separate process that the AI model never reaches. Tensol deploys each customer on a dedicated isolated VM with credentials injected at the network level. Neither model matches Nebula's undocumented security posture.

Does any Nebula alternative have persistent memory?

Vellum has the most developed persistent memory system: structured memory items with source attribution, hybrid retrieval, and per-user isolation. Lindy maintains context around your inbox and calendar preferences. OpenClaw has persistent memory as a core feature. n8n, Zapier, Gumloop, and Make do not have personal memory systems.

How does Nebula compare to Zapier?

Zapier has 7,000+ integrations versus Nebula's 1,000+, making it more complete for businesses running established SaaS stacks. Nebula is better for conversational task execution and coding agents. Zapier's workflow model is more rigid (trigger-action chains) while Nebula handles more open-ended agentic tasks.

Is there an open-source alternative to Nebula?

Several. OpenClaw, n8n, and Hermes Agent are all open source. Vellum is also open source under an MIT license. OpenClaw is the closest to Nebula in terms of personal AI assistant positioning; n8n and Hermes are better fits for technical teams building custom agent systems.

What Nebula alternative is best for teams?

Tensol for teams that want a managed, enterprise-grade deployment with dedicated infrastructure and RBAC. Gumloop for teams building specialized agents with a canvas-based workflow interface and enterprise security. n8n for technical teams that want an open-source, self-hostable platform with full code flexibility.

Does Nebula have a free plan?

Yes, Nebula offers a free plan for basic exploration. The virtual computer and full feature set require the $25/month subscription, plus additional Nebula Credits for AI model usage.

Which alternative is best for non-technical users?

Vellum and Lindy are the most accessible for non-technical users. Vellum's setup takes minutes and the assistant walks you through configuration as capabilities become relevant. Lindy's iMessage/SMS interface means you can delegate without ever opening a dashboard. OpenClaw, n8n, Hermes, and Gumloop all have meaningful setup requirements.

Can a Nebula alternative make phone calls?

Vellum can make actual phone calls on your behalf using its own voice. This is one of the capabilities that separates it from most alternatives on this list; Nebula, Lindy, Zapier, and n8n don't offer native phone call capability.

Extra Resources

• 11 Best Personal AI Assistants in 2026: Reviewed and Compared →
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• 10 Best OpenAI Operator Alternatives in 2026: Reviewed and Compared →
• 10 Best Viktor Alternatives in 2026: Reviewed and Compared →
• 10 Best Private Personal AI Assistants in 2026: Reviewed and Compared →

Citations

[1] Gravitee. (2026). State of AI Agent Security 2026 Report: When Adoption Outpaces Control. Gravitee.io. [2] Gartner. (2025, August 26). Gartner Predicts 40% of Enterprise Apps Will Feature Task-Specific AI Agents by 2026, Up from Less Than 5% in 2025. Gartner. [3] Deloitte. (2026). Agentic AI Strategy: Tech Trends 2026. Deloitte Insights. [4] Strata Identity. (2026). The AI Agent Identity Crisis: New Research Reveals a Governance Gap. Strata.io. [5] Lindy. (2026). Lindy AI Work Assistant. lindy.ai. [6] Nebula. (2026). Nebula Pricing. nebula.gg. [7] Vellum. (2026). Vellum Documentation. vellum.ai.