OverloopCampaignStack vs Overloop, compared for agencies
Overloop is one of the few tools in this set that publishes its LinkedIn limits as numbers, starts every new account at 5 actions a day and lets an algorithm raise the ceiling, and it bundles a 450-million-contact database, an email finder and AI-written emails into a $69 seat. The differences are what checks an AI draft before it goes out, what picks the next person to contact, and what a seat costs once a client has several accounts. Here is the honest side-by-side.
One team wants to source, find emails, and run LinkedIn plus email sequences from a single subscription, with the account safety rules set by the vendor rather than by a slider. Its Smart Limits are conservative by design, its database and finder are included in the seat, and the REST API plus HubSpot, Pipedrive and Salesforce syncs make it a sensible outbound layer for a sales team that already lives in a CRM.
You need the layer Overloop does not have: ICP scoring and live buying signals choosing who gets contacted, AI drafts that face a critic before a human sees them, a review queue that holds the doubtful ones, and an MCP server so an AI agent can run a client's outreach end to end. Or when a client has three or four LinkedIn accounts and per-user pricing stops making sense.
What each tool actually does
Capabilities as documented by each vendor, checked September 2026. Overloop's published limits are a real strength; so are the structural differences below.
| Capability | Overloop | CampaignStack |
|---|---|---|
| Account safety limits | Smart Limits start every new account at 5 actions a day per type and grow from activity; documented ceilings are 25 invites a day and 100 a week on a free LinkedIn account, 29 a day on Premium, and stale invitations are withdrawn after 15 to 17 days | Per-action-type daily budgets, usage-based warm-up, weekly caps, business-hours pacing, automatic risk pause, summed across every workflow on the account |
| LinkedIn outreach | Profile visit, connection request, a check-connection branch and message in the help center's list, InMail on the marketing pages, run from the cloud on IPs in the user's country; one LinkedIn account per user seat | Connection requests, messages, InMail and engagement through a persistent cloud browser per account; Sales Navigator is optional |
| Native email sending | 1 email account per user on Starter, 3 on Growth, unlimited on Enterprise, with a verifier, opt-out links and DKIM/SPF guidance; no warm-up feature is documented | Gmail sending with its own daily budgets and warm-up, inside the same workflow graph |
| LinkedIn session handling | You connect by signing in to the Overloop Chrome extension on a LinkedIn page; the help center does not document what the extension hands over or how the session is stored | Session cookie is consumed into an encrypted browser profile on our server and never stored in the database; optional recovery credentials are opt-in and encrypted |
| AI-drafted messages | Emails written per prospect from the website and social profiles, for the team to verify and edit before sending; nothing documented for LinkedIn messages or inbound replies | Openers, follow-ups and inbound replies drafted against your playbook and the lead's live context |
| Quality control on AI drafts | No quality loop exists; its FAQ says a person should review source, context, accuracy and tone before sending | A critic reads every draft against its full brief and objects; drafts that keep failing are flagged for a human |
| Human review queue | A per-email-step toggle creates a task to review, edit and approve each AI email; a separate Review Queue step holds prospects for a data check, and neither is documented for LinkedIn steps | A persistent, skippable queue where you approve, edit, retry or reject, and approving resumes the withheld action |
| Buying signals | Campaigns branch on connection status and replies, not on job changes, funding or post engagement | Job changes, title changes, post engagement, funding and headcount changes feed campaign scoring |
| ICP scoring | You describe an ICP and Overloop builds lists from its database to match it; a prospect already in your account is not scored or re-scored | Every lead is scored against every campaign's ICP; the score decides campaign membership |
| Contact database and email finder | 450 million contacts and an email finder included, at 1 credit per sourced prospect or found email, with 250, 500 or 1,000 credits per user per month by plan | No contact database; a built-in finder charges 10 credits per found email and 50 per found phone, and Apollo, Instantly or Clay can sit behind it |
| API and AI agents | REST API on Growth and above (prospects, organizations, workflows, lists, exclusion list, deals), plus Zapier; no MCP server documented | MCP server with over 300 tools; an AI agent can operate the entire platform |
| CRM sync | Two-way sync with HubSpot and Pipedrive from Growth, Salesforce on Enterprise | HubSpot write-back of worked leads; no Pipedrive or Salesforce sync yet |
| Pricing model | $69 per user a month on Starter, $99 on Growth, custom on Enterprise, where one user carries one LinkedIn account; no annual price is published | $299/mo per client workspace ($249 annual), 25,000 credits included; LinkedIn accounts and team members are not billed per seat |
Every limit in the first row is published with the mechanism behind it: the daily budget per account, the warm-up ramp, the weekly cap, and what happens when LinkedIn pushes back. See the account safety numbers
Where Overloop is genuinely strong
Most tools in this category describe their safety as a feeling. Overloop writes it down. A new LinkedIn account starts at 5 actions a day per type, the ceiling moves with what the account actually did yesterday, the documented maximums sit under LinkedIn's own weekly invitation cap, and old pending invitations are withdrawn on a schedule. You can switch Smart Limits off, and the help center tells you plainly that doing so raises your chances of being flagged. That is the right way round.
The rest of the seat is generous too. The 450-million-contact database and the email finder are inside the plan rather than sold beside it, the CRM syncs are two-way, the REST API follows the JSON API spec, and the opt-out link on every email feeds an exclusion list that blocks the address and the LinkedIn URL for every user in the account. For a sales team that wants sourcing, finding and sending from one subscription, that is a complete kit.
A person should review it. Which person, and when?
Overloop's AI writes each cold email from the prospect's website and social profiles, and its own FAQ says a person should review the source, context, accuracy and tone before sending. The mechanism for that is a toggle on the email step, which turns every send into a task in the Tasks tab: open it, edit, approve. It works, and on a list of two hundred prospects it is two hundred tasks. The alternative is to leave the toggle off and trust the draft.
CampaignStack puts a critic between the model and the human. Every draft is read against its full brief by a second model that returns one concrete objection; the draft is rewritten until it passes or, after three attempts, it is flagged and parked in the review queue with the reason attached. The person reviews the ones the system could not settle, not all of them, and approving a flagged draft resumes the withheld send. Same principle as Overloop's FAQ, applied by a machine first and a human second.
Lists execute. Nothing chooses.
Overloop's ICP feature builds a list from its database. From then on, the campaign runs the list: a prospect who changed jobs last week, or who just commented on a competitor's post, is the same row as everyone else. There is no scoring of the prospects you already hold and no standing detector that raises a hand when one of them becomes worth contacting today.
CampaignStack scores every lead against every campaign's ICP and lets live signals move that score: job and title changes, post engagement, funding and headcount events. The score decides who enters a campaign, and the whole loop, from sourcing to the review queue, is drivable over MCP by whichever AI agent your team already uses. Overloop's REST API can read and write prospects; it cannot be handed a client's outreach.
CampaignStack vs Overloop: common questions
Is Overloop cheaper than CampaignStack?
For small teams, yes. Overloop is $69 per user a month on Starter and $99 on Growth, and each user carries one LinkedIn account. CampaignStack is $299 per client workspace no matter how many accounts or people sit inside it, so the lines cross at the fifth user on Starter and the fourth on Growth. Overloop publishes no annual price and no volume tier, so a client with six seats on Growth runs $594 a month against $299 here. Add what you would pay separately for signals, scoring and a critic before comparing totals.
What LinkedIn limits does Overloop enforce?
Overloop's Smart Limits start every newly connected account at 5 actions of each type per day and raise the ceiling from the account's own activity. The documented maximums are 50 profile views, 25 connection requests (100 a week) and 50 messages a day on a free LinkedIn account, and 100 views, 29 requests and 100 messages a day on a Premium one. Pending invitations older than 15 to 17 days are withdrawn automatically. Smart Limits can be disabled, which the help center advises against. CampaignStack's limits are on its safety page: connection requests capped at 3% of the account's connections a day under a weekly cap of 100 to 200, a warm-up from 10% of the limit, and a pause of the action family on the first security check.
How does Overloop connect a LinkedIn account?
Through its Chrome extension: you install it, open it on any LinkedIn page and click Connect my Account. The actions themselves then run from Overloop's cloud on IPs located in the user's country where possible, so nothing depends on the browser staying open. The help center does not document what the extension hands over or how the session is stored. CampaignStack takes a session cookie, consumes it into an encrypted browser profile on its server and never writes it to the database.
Does Overloop have an API?
Yes, on the Growth plan and above. The REST API follows the JSON API specification and covers prospects, organizations, lists, custom fields, workflows and enrollments, deals, pipelines and the exclusion list, with an API key from Settings > API that only admins can create. It has no endpoint for sent emails or LinkedIn messages, and no MCP server is documented, so an AI agent cannot drive it the way it can drive CampaignStack's 300-plus MCP tools.
Can I migrate from Overloop to CampaignStack?
Yes. Export your prospects to CSV from the Prospects page (Manage prospects > CSV Export, delivered by email link) and import them; pull the exclusion list through the API and load it as workspace exclusions so opted-out addresses and LinkedIn URLs stay blocked from the first send. LinkedIn accounts re-onboard with a session cookie in about two minutes each. What does not transfer: your sent email history and LinkedIn conversations, which have no export, and the AI email copy, which you rebuild as workflow templates.
Will running Overloop or CampaignStack get my clients' accounts restricted?
No tool can promise it will not, and Overloop's own LinkedIn automation page says so in as many words. What both vendors can show is the mechanism. Overloop starts at 5 actions a day, grows from real activity, caps invitations under LinkedIn's weekly limit and withdraws stale ones. CampaignStack caps connection requests at 3% of the account's connections a day under a weekly cap of 100 to 200, warms up from 10% of the limit, paces sends across business hours with a per-account start time that moves daily, runs one static residential proxy and one encrypted browser profile per account, and pauses the challenged action family on the first security check. Every number is on the safety page.
Can I not just do this with Claude or ChatGPT directly?
Claude or ChatGPT will write you a good message today. What neither can do on its own is hold a LinkedIn session, keep an account under a daily budget, notice that the person replied four days ago, or stop when a meeting gets booked. CampaignStack is those parts. The model writes, the system decides who, when and how many, and a review queue sits in front of every send. If you already run an agent, connect it to the MCP server and it gets the same guardrails.
Every claim about the competitor on this page was checked against these pages on its own site:
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