# Allegrow

> Allegrow is a B2B email deliverability and verification platform, built by Scottish company Direct Software Limited, that plugs natively into Outreach, Salesloft, and HubSpot to block risky sends before they leave the sequencer (its Safety Net), tracks per-sender spam rates from real B2B inboxes, and verifies hard-to-resolve addresses, including catch-all domains and contacts behind secure email gateways like Proofpoint and Mimecast.

- Category: Email Deliverability & Warming (https://saastracker.org/categories/email-deliverability)
- Website: https://www.allegrow.co
- Starting price: $99/mo (Starter, 5,000 verifications)
- Free plan: No
- Free trial: 14 days, up to 1,000 verifications; no integrations, API, or mailbox connection during trial
- Founded: 2018, HQ: Glasgow, Scotland, UK (registered as Direct Software Limited; operations in the UK and USA), Ownership: Venture-backed
- Profile last reviewed: 2026-08-22
- Canonical profile: https://saastracker.org/products/allegrow

## Overview

Allegrow occupies a position nobody else in this category holds: it lives inside the sales engagement platform. Rather than warming mailboxes from the outside or running seed tests after the fact, Allegrow's Safety Net inspects every email scheduled in Outreach, Salesloft, or HubSpot before it sends, and reverts risky ones (invalid addresses, spam traps, contacts likely to bounce) to drafts. Combined with per-user spam-rate tracking sourced from real B2B inboxes with unique postmaster signatures rather than simulated seed accounts, it gives revenue teams a daily, sender-by-sender read on what percentage of their traffic is reaching the primary inbox.

As of 2026 the company leads its marketing with the verification engine underneath that protection. Allegrow positions itself as the B2B verifier that returns conclusive Valid or Invalid statuses where ordinary tools return Unknown: it resolves catch-all domains (claiming around 30 percent more valid enterprise contacts recovered), navigates secure email gateways like Proofpoint and Mimecast through automated greylisting resolution, and detects spam traps, disposables, dead inboxes, and non-primary aliases. That engine is sold to GTM teams, to data providers who embed it via API, and to AI-agent workflows, with SOC 2 Type 1 certification, GDPR compliance, SSO, and a Claude MCP integration signaling the enterprise and automation ambitions.

The pricing tells you who this is for. A Starter tier at $99 a month covers 5,000 verifications with a single monitored mailbox, but the flagship Scale Plus Unlimited plan runs $1,340 a month billed annually for unlimited verification, native sequencer integrations, and a dedicated customer success manager. That puts Allegrow an order of magnitude above the warming networks (Warmbox, Mailivery, Warmup Inbox) in this category, and its buyers are correspondingly different: funded outbound teams and data companies for whom a burned domain or a dirty dataset costs far more than the subscription. Backers include Sequoia-affiliated investors across roughly $1.5M raised since the 2018 founding in Glasgow.

## How it works

1. You connect Allegrow to your sales engagement platform (Outreach, Salesloft, or HubSpot; the vendor says the integration completes in about a minute) and to your sending mailboxes. From then on, every email scheduled in a sequence passes through Allegrow's contact analysis before it leaves.

2. The Safety Net checks each recipient in real time: SMTP-level validation, catch-all resolution through proprietary greylisting techniques, spam-trap and disposable detection, and risk scoring. Emails to addresses that would bounce or damage reputation are reverted to drafts instead of sent, so bad data is caught at the moment of send rather than discovered in a bounce report.

3. In parallel, Allegrow measures outcomes from the receiving side. Its placement data comes from real B2B inboxes with unique postmaster signatures, and dashboards break spam rate and primary-inbox rate down per sender, per department, and per domain, daily, so a manager can see which SDR's sending health is deteriorating and intervene before a domain-wide problem develops. Authentication monitoring watches SPF, DKIM, and DMARC configuration and alerts on drift, and content testing gives feedback on which templates are more likely to clear filters.

4. For list-level and programmatic use, the same verification engine runs over CSV uploads, native CRM integrations, Clay via API key, or the REST API (with a Claude MCP server for agent workflows). Data providers and platforms embed the API at millions of requests a month under custom plans, mixing verification methods and reselling results downstream.

## Best for

Funded B2B revenue teams running high-volume sequences through Outreach, Salesloft, or HubSpot who want risky sends blocked automatically and spam rates tracked per SDR, plus data providers and automation builders who need conclusive verification of catch-all and gateway-protected enterprise addresses at API scale.

## Not the right fit for

- Small teams and solo senders; at $99 a month for 5,000 verifications and $1,340 a month for the unlimited plan, Allegrow costs multiples of what most of this category charges, and the value concentrates in sequencer integrations small teams do not run.
- Teams whose primary need is mailbox warming; Allegrow prevents damage and measures placement but is not a warming network, so a new domain still needs a Warmbox, Mailivery, or MailReach-style tool to build initial reputation.
- Senders outside Outreach, Salesloft, and HubSpot; the Safety Net's pre-send interception is the signature feature, and teams on other sequencers get only the verification and monitoring layers.
- Marketers running newsletters or lifecycle email; Allegrow is built around B2B outbound and corporate address resolution, not consumer list hygiene or campaign placement testing.

## Features

### Safety Net (pre-send protection)

The signature capability: risky emails stopped inside the sequencer before they send.

- **In-sequencer send interception**: Analyzes every email scheduled in Outreach, Salesloft, or HubSpot and reverts risky sends to drafts before they leave, preventing bounces and spam-trap hits rather than reporting them afterward.
- **Spam-trap detection and blocking**: Identifies known and suspected spam traps that sneak into sequences and blocks sends to them, protecting domain reputation from its most severe single hazard.
- **Real-time bounce prevention**: Invalid and high-risk addresses are removed from send queues as they are detected; customer Spring Labs reports bounce rates held below 3 percent.
- **Risk scoring per contact**: Each recipient carries a risk assessment combining validity, trap likelihood, and engagement hazard, so borderline contacts can be reviewed instead of silently sent.

### B2B verification engine

Conclusive resolution of the addresses ordinary verifiers mark Unknown.

- **Catch-all domain resolution**: Returns definitive Valid or Invalid statuses on catch-all servers, which Allegrow claims recovers roughly 30 percent more valid enterprise contacts than tools that punt with Unknown.
- **Secure email gateway resolution**: Navigates Proofpoint, Mimecast, and similar gatekeepers through automated greylisting resolution, verifying enterprise contacts most SMTP-only verifiers cannot see behind the gateway.
- **Spam-trap, disposable, and dead-inbox detection**: Flags addresses that would poison a list: traps, throwaway domains, and mailboxes that exist but are no longer read.
- **Primary email detection**: Distinguishes a person's active primary address from secondary aliases, so outreach lands where decision-makers actually read.
- **Managed quality IPs**: Verification traffic runs over dynamically managed proxy infrastructure to keep the checks themselves from being blocked or degraded.

### Deliverability monitoring

Placement and reputation measurement from the receiving side, per sender.

- **Per-user spam-rate tracking**: Daily breakdown of what percentage of each sender's traffic reaches the primary inbox versus spam, benchmarked across the team so managers can spot the SDR whose sending health is slipping.
- **Real-inbox placement data**: Measurement comes from real B2B inboxes with unique postmaster signatures rather than simulated seed accounts, per the vendor.
- **Domain reputation and health tracking**: Continuous monitoring of sender reputation per domain with alerts when metrics move in the wrong direction.
- **Authentication monitoring**: Confirms SPF, DKIM, and DMARC remain correctly configured and alerts on drift, the silent misconfigurations behind many placement collapses.
- **Content and template testing**: Tests which templates and sequences are more likely to clear spam filters and prompt engagement, feeding copy decisions with placement evidence.

### Integrations and workflow

Native placement inside the GTM stack rather than a standalone dashboard.

- **Outreach, Salesloft, and HubSpot native integrations**: Verified marketplace integrations that operate inside the sequencer's own scheduling flow; setup completes in about a minute per the vendor.
- **Clay integration**: Verification runs inside Clay enrichment workflows via API key, catching bad addresses at the list-building stage.
- **Automated workflow rules**: Rules for CRM hygiene and secure-gateway handling automate what happens to contacts as verification statuses come back (Scale Plus and above).
- **CSV bulk verification**: Straightforward upload-and-clean for lists outside the integrated stack.

### API, platform, and enterprise

The layer sold to data providers, platforms, and security-conscious buyers.

- **REST API with signal transparency**: Granular verification API returning the underlying signals, not just a verdict; capped at 1M requests a month on Scale Plus, with custom plans for millions more.
- **Claude MCP integration**: A Model Context Protocol server lets AI agents run verification inside automated GTM workflows, an early move toward agent-driven outbound plumbing.
- **Resell and embed rights**: Custom API plans allow data providers to embed Allegrow verification in their own products and datasets, with custom verification-method mixing.
- **SOC 2 and enterprise security**: SOC 2 Type 1 certification, GDPR compliance with DPAs, and SSO availability, ahead of most of this category on paper security.
- **Dedicated customer success**: Scale Plus and API plans include a named CSM and dedicated technical support channels rather than ticket-queue support.

## Use cases

- **RevOps leader at a scaling SaaS company**: Forty SDRs send through Outreach, bounce rates creep up with every new data source, and one bad list segment could blacklist the primary domain before anyone notices. Outcome: Safety Net reverts risky sends to drafts automatically, per-user spam-rate dashboards show which reps' sending health is deteriorating, and bounce rates hold under 3 percent without manual list policing.
- **Data provider selling B2B contact records**: A meaningful share of enterprise addresses in the dataset sit behind catch-all domains and Proofpoint gateways, and every Unknown status undercuts the product's accuracy claims. Outcome: The custom API plan embeds catch-all and gateway resolution into the pipeline at millions of requests a month, converting Unknowns into conclusive statuses the provider can stand behind and resell.
- **Enterprise sales team selling into gated industries**: Targets in finance and healthcare run Mimecast and Proofpoint, ordinary verifiers return Unknown on half the list, and reps burn sequences on dead addresses. Outcome: Greylisting-based gateway resolution and primary-email detection recover verified addresses for gated accounts, so sequences spend touches on contacts who exist and read the mailbox.
- **Automation builder wiring agent-driven outbound**: An AI workflow assembles prospect lists and drafts sequences autonomously, and unverified data flowing straight to a sequencer is the failure mode that burns domains at machine speed. Outcome: Verification runs inside the workflow via the REST API and Claude MCP server, so every agent-sourced contact is resolved before any send is scheduled.

## Pricing

Subscription tiers metered on monthly verification volume, with an unlimited flagship tier billed annually and custom API plans for embedded, high-volume use; a 14-day free trial covers 1,000 verifications.

- **Starter**: $99 per month. 5,000 verification contacts/month; CSV upload; API access on request; 1 mailbox connection for domain health tracking; Clay integration via API key; Add-on credits at $8 per 1,000 contacts. No native sequencer integrations at this tier; additional users or mailboxes run $40 each per month.
- **Scale Plus Unlimited**: $1,340 per month, billed annually. Unlimited verification across integrations and CSV; Native Outreach, Salesloft, and HubSpot integrations; API capped at 1M requests/month; Automated workflow rules for CRM and secure gateways; Dedicated CSM, SSO, SOC 2 reports.
- **API (custom)**: Custom per month. Millions of API requests/month; Greylisting resolution and custom verification-method mixing; Resell and embed rights for data partnerships; Dedicated technical support channels.

Add-ons:

- Additional verification credits (Starter) ($8 per 1,000 contacts)
- Additional users or mailbox connections (Starter) ($40 per mailbox/user per month)

Billing notes:

- Scale Plus Unlimited's $1,340 a month is an annual commitment (roughly $16,000 a year), a genuine enterprise line item; confirm current terms with sales before budgeting.
- The gap between tiers is a cliff: nothing published sits between $99 Starter and $1,340 Scale Plus, so teams outgrowing 5,000 verifications face a large jump or per-credit add-ons at $8 per 1,000.
- The trial excludes the integrations, API, and mailbox connection, which means the Safety Net, the product's signature feature, cannot be evaluated on the free trial.
- Starter's API access is granted on request rather than self-serve, and native sequencer integrations require Scale Plus.

Value assessment: Allegrow's price only makes sense against the cost of the failures it prevents, and for its target buyer that math works: one blacklisted primary domain, one poisoned dataset, or one quarter of sequences burned on dead enterprise addresses costs more than a year of Scale Plus. The catch-all and gateway resolution genuinely recovers contacts other verifiers cannot conclusively verify, which for enterprise-focused teams converts directly to pipeline. But buyers should be clear-eyed about the cliff between $99 and $1,340, the annual commitment, and the fact that the trial cannot exercise the Safety Net; mid-market teams that mostly need list cleaning will get most of their value from a far cheaper verifier like MailerCheck.

## Strengths

- The Safety Net's pre-send interception inside Outreach, Salesloft, and HubSpot is a genuinely unique mechanism in this category: prevention at the moment of send rather than diagnosis after it.
- Catch-all and secure-gateway resolution (Proofpoint, Mimecast) returns conclusive verdicts on the enterprise addresses ordinary verifiers mark Unknown, the hardest and most valuable segment of B2B data.
- Per-user spam-rate tracking from real B2B inboxes gives sales managers an accountability view (which SDR's sending health is slipping) no seed test or warmer provides.
- Enterprise posture is real: SOC 2 Type 1, GDPR with DPAs, SSO, dedicated CSMs, and named customers including Algolia, Domo, and Workvivo.
- The API layer with resell rights, signal transparency, and a Claude MCP server makes Allegrow infrastructure for data providers and agent-driven workflows, not just an end-user tool.
- Documented customer outcomes (bounce rates under 3 percent at Spring Labs, large reply-rate gains at Workvivo) are more specific than the vague lift claims common in this category.

## Limitations

- Pricing excludes most of the market: $1,340 a month billed annually for the tier where the product fully works, with a bare $99 tier and nothing in between.
- No warming capability; a new domain still needs a separate warm-up tool before Allegrow's protection and measurement have anything healthy to protect.
- The signature Safety Net only exists inside Outreach, Salesloft, and HubSpot; teams on Instantly, Smartlead, Apollo, or lemlist get a verifier and monitor, not the pre-send layer.
- The free trial excludes integrations, API, and mailbox connection, so the features that justify the price cannot be tested without a sales conversation.
- Small vendor risk on an enterprise price: roughly 9 to 10 employees and $1.5M raised, so procurement teams paying five figures a year are betting on a very small company.
- SOC 2 is Type 1 (a point-in-time design review), not the Type 2 operating-effectiveness audit larger security teams typically require.

## Comparisons

- **Allegrow vs MailerCheck**: Both verify email, but for different buyers: MailerCheck sells pay-as-you-go verification at a cent a check with light placement and content testing for marketers; Allegrow sells conclusive catch-all and gateway resolution, pre-send protection inside sequencers, and per-SDR spam tracking at enterprise prices. Clean a list for $50 with MailerCheck; protect a 40-seat outbound motion or a commercial dataset with Allegrow.
- **Allegrow vs GlockApps**: GlockApps measures placement from a seed panel and parses DMARC for anyone who sends; Allegrow enforces deliverability inside the B2B sequencer, blocking risky sends and tracking per-sender spam rates from real B2B inboxes. Marketers and consultants auditing placement pick GlockApps; revenue teams that want bad sends stopped automatically pick Allegrow, at several times the price.
- **Allegrow vs Folderly**: Both are premium deliverability suites, but Folderly bundles warming, auditing, and managed services as an ops layer, while Allegrow bundles verification, pre-send enforcement, and sender analytics as a data-quality layer inside the sequencer. Teams whose problem is reputation and placement lean Folderly; teams whose problem is list quality and SDR sending discipline lean Allegrow.
- **Allegrow vs MailReach**: MailReach builds reputation through warming with a placement test attached, at a per-inbox price a bootstrapped team can pay; Allegrow assumes reputation exists and defends it by stopping bad sends and cleaning data at enterprise scale. They are complements more than rivals: warm with MailReach, then a scaled team graduates to Allegrow-style enforcement as sequence volume grows.

## Implementation

- Setup time: The sequencer integration connects in about a minute per the vendor; realistic rollout, including workflow rules, CRM hygiene automation, and team dashboards, is measured in days, not months.
- Learning curve: Low for end users, since enforcement is automatic once configured; moderate for admins tuning risk thresholds, workflow rules, and per-team reporting.
- Onboarding: Scale Plus and API plans include a dedicated customer success manager and technical support channels; Starter is self-serve.
- Migration: Allegrow layers onto an existing sequencer and CRM rather than replacing anything, so adoption and removal are both low-friction; leaving costs you the historical spam-rate and verification data, not your sending stack.

## Platform, API & security

- Platforms: Web app, REST API, Claude MCP server
- API: REST API with full signal transparency and configurable verification methods; 1M requests a month on Scale Plus, custom volumes with resell and embed rights on API plans. Starter gets API access on request.
- Compliance: SOC 2 Type 1, GDPR (DPAs available)
- Data residency: Not publicly specified; the company operates from the UK and USA.
- SSO: Available on Scale Plus and API plans.
- Security notes: Verification runs over managed proxy infrastructure; sequencer integrations operate through verified marketplace apps. SOC 2 reports are available to customers on qualifying plans; the certification is Type 1 as of this review.

## Support

- Channels: Email support, Dedicated CSM (Scale Plus and above), Dedicated technical channels (API plans)
- Documentation: A knowledge base covering deliverability practice, sequencer setup, and verification methodology.
- Community: No user community; the ecosystem runs through the Outreach, Salesloft, and HubSpot marketplaces.

## Company

- Founded: 2018
- Founders: Ruari Baker, Kieran Baker, Radu Oprea
- Headquarters: Glasgow, Scotland, UK (registered as Direct Software Limited; operations in the UK and USA)
- Ownership: Venture-backed
- Employees: ~9 to 10 (third-party trackers, 2026)
- Funding: Roughly $1.5M raised across 2 rounds; investors include Sequoia-affiliated programs, Northstar Ventures, and Golden Section.

Funding history:

- Early-stage rounds (2019-2022): $1.5M total. Two rounds reported by public trackers; individual round details are not fully disclosed.

Timeline:

- 2018: Direct Software Limited founded in Glasgow; Allegrow launches as a deliverability platform keeping B2B email out of spam.
- 2020: Raises early funding (roughly $1.5M across two rounds) from investors including Northstar Ventures and Sequoia-affiliated programs.
- 2022: Safety Net matures inside Outreach and Salesloft, reverting risky scheduled emails to drafts, and per-user spam-rate analytics differentiate the platform from seed-test tools.
- 2024: HubSpot joins the native integration roster and SOC 2 Type 1 certification lands, sharpening the enterprise posture.
- 2026: Repositions around enterprise B2B verification: catch-all and secure-gateway resolution, an unlimited Scale Plus tier, custom API plans with resell rights, and a Claude MCP server for agent workflows.

## Integrations

Outreach (native), Salesloft (native), HubSpot (native), Clay (via API key), REST API, Claude MCP

## FAQ

### What does Allegrow do?

Allegrow protects B2B email deliverability from inside the sales stack: it verifies addresses (including catch-all domains and contacts behind Proofpoint or Mimecast gateways), blocks risky emails scheduled in Outreach, Salesloft, or HubSpot before they send, and tracks spam rates per sender using data from real B2B inboxes.

### What is Allegrow's Safety Net?

It is a pre-send protection layer inside supported sequencers. Every scheduled email is analyzed in real time, and sends to invalid addresses, spam traps, or high-risk contacts are reverted to drafts instead of going out, preventing the bounces and trap hits that damage domain reputation rather than reporting them afterward.

### How much does Allegrow cost?

Starter is $99 a month for 5,000 verifications with CSV upload and one monitored mailbox. Scale Plus Unlimited is $1,340 a month billed annually with unlimited verification, native Outreach, Salesloft, and HubSpot integrations, a 1M-request API cap, and a dedicated CSM. Custom API plans cover millions of monthly requests with resell rights.

### How is Allegrow different from a normal email verifier?

Two ways: resolution depth and placement in the workflow. It returns conclusive Valid or Invalid verdicts on catch-all domains and gateway-protected addresses that standard SMTP verifiers mark Unknown, and it applies verification at the moment of send inside the sequencer rather than only as an upstream list-cleaning step.

### Does Allegrow warm up mailboxes?

No. Allegrow prevents reputation damage and measures placement, but it does not run a warming network. New domains still need a warm-up tool such as MailReach, Warmbox, or Mailivery to build initial sender reputation before high-volume sequencing.

### Which platforms does Allegrow integrate with?

Native, marketplace-verified integrations with Outreach, Salesloft, and HubSpot, plus Clay via API key and a REST API with a Claude MCP server for automated and agent-driven workflows. The pre-send Safety Net only operates inside the three native sequencer integrations.

### How does Allegrow verify catch-all and gateway-protected addresses?

It combines SMTP validation with proprietary automated greylisting resolution, which coaxes conclusive accept-or-reject behavior out of catch-all servers and secure gateways like Proofpoint and Mimecast. Allegrow claims this recovers roughly 30 percent more valid enterprise contacts than tools that return Unknown on those domains.

### Where does Allegrow's spam-rate data come from?

From real B2B inboxes with unique postmaster signatures rather than simulated seed accounts, according to the vendor. Dashboards break the resulting placement data down per sender, per department, and per domain daily, so managers can see exactly whose sending health is deteriorating.

### Is Allegrow SOC 2 certified?

Yes, SOC 2 Type 1, with GDPR compliance, DPAs, and SSO available on qualifying plans. Note that Type 1 is a point-in-time design assessment; security teams requiring an operating-effectiveness audit should ask about Type 2 status directly.

### Who is behind Allegrow?

Allegrow is built by Direct Software Limited, founded in Glasgow, Scotland in 2018 by Ruari Baker, Kieran Baker, and Radu Oprea. The company operates in the UK and USA with roughly 9 to 10 employees and about $1.5M raised, and counts Algolia, Domo, Workvivo, and Quantum Metric among named customers.

## Editorial verdict

Allegrow is the enforcement layer of this category, and nothing else here occupies its spot: verification deep enough to resolve catch-alls and Proofpoint-gated addresses conclusively, wired directly into the sequencer so bad sends are stopped rather than diagnosed. For a scaled outbound team on Outreach, Salesloft, or HubSpot, or a data provider whose product is accuracy, it earns its enterprise price by preventing failures that cost multiples of the subscription. Everyone else should notice what it is not: not a warmer, not cheap, not fully testable on trial, and not especially useful outside its three native sequencers. Buy Allegrow when list quality and sending discipline at scale are the problem; buy a warmer plus a $50 verifier when they are not yet.

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Source: SaaSTracker (https://saastracker.org), an independent editorial project. This profile is compiled from public information, carries no peer reviews or paid placement, and was last reviewed 2026-08-22. Awards are judged on published criteria: https://saastracker.org/methodology