Relay vs Vessel Browser

Relay and Vessel Browser are both workflow automation tracked by AIDiveForge. Below is a side-by-side comparison of pricing, capabilities, platforms, and ownership — sourced from each tool's live website and verified before publishing.

Relay

Relay.app lets you describe a workflow in plain language, then generates a visual step sequence you can edit manually or by prompting again. The core model is fixed-sequence automation — triggers, steps, branches, loops — with AI inserted at specific points for extraction, summarization, or creation, not for deciding what to do next. Approval gates are built in, not bolted on, so a finance director can sign off on an expense before it routes to payment. Reusable 'Sequences' let teams standardize common patterns like lead enrichment or onboarding and propagate updates across every workflow at once. The ceiling appears when logic grows complex: deep conditional branching across many steps pushes against what the visual canvas expresses cleanly.

Vessel Browser

Vessel exposes 80+ browser tools over MCP — navigate, click, fill, extract, diff, checkpoint, undo — so any MCP-compatible agent harness can drive a real browser without brittle Playwright scripts or headless guesswork. The visible-by-default design means you can watch, pause, approve, or roll back before something ships. Session persistence and named checkpoints mean the agent picks up where it left off instead of re-authenticating from scratch every run. The wall appears on complex, multi-site workflows that branch based on what the last page returned — the built-in skill system handles linear recipes well, but conditional logic across domains requires more than reusable instructions. Saved sessions, credential vaults, and page-change history are paid-only features, so teams running fully autonomous monitoring pipelines hit that ceiling fast.

Attribute	Relay	Vessel Browser
Pricing	Paid	Paid
Price	$19/mo	$5.99/month
Free trial	No	7 days
Open source	No	Yes
Has API	Yes	Yes
Self-hosted option	No	Yes
Platforms	Web-based SaaS (cloud only)	Linux, Windows, Mac
Released	2021	—
Pros	Human approval gates are first-class workflow steps — not external integrations — so run history captures every decision point and teams have a built-in audit trail without adding a separate compliance tool. Natural language workflow generation means an ops manager can describe a process and get a working visual draft without writing automation logic, so the gap between 'I want to automate this' and 'this is running in production' shrinks to hours instead of days. Reusable Sequences let teams define common patterns — lead enrichment, approval routing, onboarding steps — once and update them in one place, so a process change doesn't require editing twenty individual workflows. AI steps are inserted at specific points in a fixed sequence for tasks like data extraction, summarization, or transcription, which means the output is predictable and auditable rather than generated on the fly where errors compound silently. Integration with 200+ apps, including financial tools like Stripe, QuickBooks, and Xero alongside CRMs and communication platforms, so most mid-market operations stacks connect without custom API work.	Visible-by-default browser with pause, approve, and deny controls on every agent action, so you catch credential submissions or form commits before they execute rather than after. Named checkpoints and session restore so the agent resumes a logged-in, mid-task state across runs — eliminating the re-authentication loop that breaks most headless automation after the first session expires. 80+ structured MCP browser tools covering navigation, extraction, diffing, and undo, which means any MCP-compatible agent harness can drive a real browser without you writing and maintaining custom Playwright wrappers. MIT-licensed and fully self-hosted, so session cookies, credentials, and page data never leave your machine — which matters the moment a workflow touches accounts you do not want proxied through a cloud service. Bring-your-own-model support via OpenAI-compatible endpoints, so swapping the underlying model when costs shift or a local model improves is a config change, not a migration.
Cons	Complex conditional logic — four or more branches where each path has its own sub-conditions — strains the visual canvas. Teams building multi-path decision trees end up adding workarounds or restructuring workflows in ways that obscure the logic; at that point, a code-first tool like n8n or a purpose-built BPM platform handles the same requirements with less contortion. Relay.app is not self-hosted and offers no self-hosted option, so teams with data residency requirements or internal-only network policies cannot run it in their own infrastructure — those teams evaluate on-premise alternatives before the trial ends. The platform executes predefined sequences and does not support autonomous goal decomposition, persistent memory across runs, or self-directed iteration — teams that arrive expecting agent behavior discover the tool is workflow-first and must either restructure their expectations or switch to an agent framework like LangGraph or CrewAI for that work.	Saved sessions, credential vaults, and page-change history are paid-only features — teams building unattended monitoring pipelines on the free tier hit this wall the first time an agent needs to resume a session it did not start in the current run, and the options are upgrade or build session persistence themselves. The reusable skills system handles linear, site-specific routines well but has no native conditional branching — when an agent needs to take different paths based on what a page returned, teams add a separate orchestration layer on top of Vessel, which means two codebases to maintain instead of one; at that complexity level, teams with existing Playwright or Puppeteer infrastructure tend to stay there rather than migrate. The project carries 60 GitHub stars and community reports of 10K+ NPM downloads — a small signal base, which means production edge cases surface without much prior documentation, troubleshooting threads, or community-vetted workarounds to reference.

Bottom line

Vessel Browser is open source. Choose based on which difference matters most for your workflow.

Frequently asked questions

What is the difference between Relay and Vessel Browser?

Relay is Paid, while Vessel Browser is Paid and open source. Compare pricing, free trial, API, platforms, and pros/cons in the table above on AIDiveForge.

Is Relay better than Vessel Browser?

It depends on your workflow. Use the side-by-side attributes (pricing, open source, API, self-hosted, platforms) to decide. AIDiveForge does not rank a universal winner — we publish verified facts so you can choose.