Best signal-based outbound tools 2026: 14 compared by price

The best signal-based outbound tool depends on what should happen after the signal. Sellers who run outreach themselves can add signals to sequences in Unify (from $20 a seat a month) or Apollo ($49); HubSpot teams can use its prospecting agent at $1 per lead; Gojiberry ($99 a month), Valley ($149 a seat a month) and AiSDR ($1.50 per person) write and send for you; Clay ($167 a month) suits builders; and Amplemarket ($600 a month), Warmly ($15,000 a year), Common Room ($2,500 a month) and UserGems ($40,000 a year) are priced for larger budgets. Checked on 15 October 2026, approval before sending is the default in Amplemarket's Duo and Unify's AI-written sequences, while AiSDR and Clay have no per-message approval.

Revexa builds Leo, one of the tools below. Which signals each tool tracks is compared in buying signal tools compared; this page covers who writes, who approves, the channels and the build.

Order: the lowest monthly US dollar list price of a paid plan that turns signals into outreach, any billing term; free plans and limited-time offers don't count, ties are alphabetical, and Hunter, with no public price, is last. AiSDR, with no monthly fee, sits at about $225 a month: its lowest pace, 5 people a day at $1.50, for 30 days (our estimate from AiSDR's pricing).

The 14 tools compared

Prices exclude VAT and sales tax; more in our sales tool pricing research. Trigify, a signal feed for many teams, closes for most customers at 11:59pm BST on 22 October 2026 (Trigify); see Trigify alternatives.

How each tool turns a signal into outreach

HubSpot. The prospecting agent watches signals you pick per play, such as funding, leadership changes and site visits, and drafts "in each rep's voice" (product page). Each play offers "Review emails" or "Send without review" and sends on business days in a window you set (HubSpot KB). A lead costs 100 credits ($1); Starter includes 500 a month (catalog). Setup: signal-based outbound in HubSpot.

Unify. In chat-built sequences Unify writes each person's drafts, and "You review the content and approve each person before their sequence begins"; enrolling from a person's record skips that review (docs). Website intent and "Signal-triggered automations" need the custom, annual Business plan.

Apollo. A workflow can start when a contact "experiences a job change", then enroll people automatically or create review tasks first (overview, settings). "Automatic email steps send without someone completing a task"; LinkedIn and call steps become tasks (help).

Gojiberry. Its source agent "launches multiple times per day", and its outreach agent runs LinkedIn and email steps on a daily schedule within your launch hours (help). With Review Mode on, "you approve each lead and message before they are sent" (quick start).

Leo by Revexa (ours). Leo builds your ideal customer profile from your website and watches hiring, funding, new executives in the buying role, engagement with competitors' and industry voices' LinkedIn posts, competitors' tools on a company's site and job ads such as Sweden's Platsbanken. It drafts LinkedIn messages and emails to the right person in your voice, in the lead's language when your website exists in that language, otherwise English. Review mode is the default: you edit, approve or skip each draft in the portal, iMessage or Slack, and autonomy is opt-in per channel. Sending runs weekdays 08 to 17 in the recipient's time zone. Leo automatically blocks cold messages to leads in Germany (UWG §7) and in no other country, so in markets with consent rules, such as Denmark and Norway, you decide as you approve each draft. No customer results are published.

Valley. Valley finds prospects among LinkedIn post engagers, profile viewers and competitors' post engagers (pricing). With its autonomous setting off, "every message queues in Approvals"; the help center recommends turning it on "for most users" (help).

Clay. You build the flow: job-change, news and social signals on Launch, web intent and webhooks from Growth. Clay's Sequencer, generally available since 1 September 2026, sends email; launching the campaign is the approval, and afterwards new leads "will automatically be sequenced" (docs, launch post).

AiSDR. Its agent builds an email and LinkedIn campaign from your website, using live signals such as job changes, new hires and funding. You approve "the sequence structure and tone" before launch; then "No manual approval is needed for each outgoing message" (help).

Salesforge (Agent Frank). Frank "researches each prospect, their company, buying signals and timing", and in Co-Pilot mode "he will ask for your review before sending messages" (Agent Frank). The page lists 21 languages, Swedish, Danish, Norwegian and Finnish among them.

Amplemarket (Duo). "Duo uses AI agents to scan your market daily for buying signals", and the rep can "Send or dismiss each lead" (Duo, lesson). An optional mode, set per signal, "schedules outreach for Duo-recommended leads without waiting for manual review" (lesson).

Warmly. Its orchestration "automatically initiates multi-channel outreach (email, LinkedIn, phone) when accounts show buying intent", with "AI drafts, rep approves" as one routing option (Warmly). HubSpot has agreed to acquire Warmly (announced 30 June 2026) (Warmly).

Common Room. RoomieAI "writes personalized outreach from person-level intent and account context", and "Human-led review stays in the loop" (RoomieAI). Zoom says its purchase of Common Room closed in July 2026 (Zoom).

UserGems. Gem-E "drafts email sequences, call scripts, LinkedIn messages for your team" from signals such as past champions changing jobs, and delivers them into your CRM and sales engagement tool (Gem-E).

Salesforce Hunter. Hunter "works a sales pipeline from research to outreach" and is listed as "Pilot now; GA November ’26" (Salesforce). It asks for access to your email account to send on your behalf, and customer-facing actions "can require rep approval before they execute" (walkthrough, Hunter).

From signal to meeting in five steps

1. Fit first. Decide which companies you can help before you watch for events, so a signal ranks companies that already fit instead of replacing fit. Topic data can help with the ranking (intent data providers compared).
2. Pick two or three signals with a reason. In Bloomberry's analysis of about a million software purchases from March to September 2025, companies that grew headcount by 20% or more made 38% more purchases, companies that hired a VP 28% more and recently funded startups 25% more, against 7% for rising job openings (Bloomberry). It is a correlation study by a data vendor, not a controlled test.
3. Find the person who owns the problem. The account is not the buyer.
4. Write from the signal to the problem, and read the first batches. The signal explains why now; the message must explain why you.
5. Send within days, keep customers and open deals out, stop on any objection and log the result, so you learn which signals lead to meetings.

What goes wrong

The wrong person. Forrester says "The typical buying decision now includes 13 internal stakeholders and nine external influencers" (Forrester, 2026). Company-level signals name a company, not the buyer.

Too late, or too early. In HBR's study of 1.25 million web leads, firms that tried within an hour were "nearly seven times as likely to qualify the lead" as those that waited even an hour longer (HBR, 2011). That measured inbound queries, not outbound signals, but 6sense's 2025 survey of nearly 4,000 buyers points the same way: first contact came at 61% of the journey, and the winner was on the day-one shortlist 95% of the time (6sense). Approval queues add delay: Valley warns that if nobody checks the queue, messages "pile up and never send. Your warm signals go cold." (Valley help). Some signals come early: Bloomberry suspects job openings are "too early of an indicator", and McKinsey found in 2017 that 92% of external and 72% of internal new leaders take far more than 90 days to reach full speed (McKinsey).

Generic messages. In Gartner's survey of 632 B2B buyers, "73% of B2B buyers actively avoid suppliers who send irrelevant outreach" (Gartner, 2025). Naming the funding round is not relevance; linking it to a problem you solve is.

Signal-based outbound in Europe

• GDPR. Direct marketing "may be regarded as carried out for a legitimate interest" (recital 47, article 6(1)(f)); people must learn where you got their data "at the latest at the time of the first communication" (article 14(3)(b)), and an objection means it "shall no longer be processed for such purposes" (article 21(3)) (GDPR).
• Email rules differ by country. Germany requires prior express consent for advertising by electronic mail, with no exception for businesses (UWG §7). Denmark bans direct marketing by electronic mail to "nogen", anyone, without prior consent (§ 10). Norway requires consent for natural persons (§ 15), which its Consumer Authority applies to named work addresses (guidance). Sweden requires it only for natural persons, and every email needs an opt-out address (19 and 20 §§).
• Data and language. Warmly offers "no personal-level anonymization in Europe" (Warmly help). HubSpot's agent can write in the contact's preferred language. Whether a tool blocks a country automatically varies, so ask before you connect a mailbox.

This is not legal advice.

Common questions

What is signal-based outbound?

Outreach started by an event at a company that fits your customer profile, such as a new executive, a funding round or a hiring push, instead of a static list.

Which signal-based outbound tools let me approve messages first?

By default in Amplemarket's Duo (each lead) and Unify's AI-written sequences (each person); the table shows the rest. As an option in HubSpot, Gojiberry, Valley, Salesforge and Warmly. AiSDR and Clay have no per-message approval. More in approval, tool by tool.

What is the cheapest signal-based outbound tool?

Unify, Apollo and Clay have free plans to test with. Among paid plans, Unify Base and HubSpot Starter cost $20 a seat a month (HubSpot adds $1 per lead), Gojiberry $99 a month, and AiSDR $1.50 per person contacted.

Is signal-based outbound legal under GDPR?

The data processing can rest on legitimate interest (GDPR recital 47), with information at first contact and a stop on objection. Whether you may send email is a separate, national rule: Germany and Denmark require consent even for businesses. This is not legal advice.