BlackStack

What BlackStack does

BlackStack is a Chrome extension-based snippet manager that lets knowledge workers store, organize, and deploy reusable text templates across the web applications they already use. The product runs as a browser extension paired with a web app backend and supports text triggers, content capture, fuzzy search, and visual folder organization. It integrates directly with Gmail, Outlook, LinkedIn, Salesforce, HubSpot, Reddit, and multiple LLM chat interfaces, allowing users to expand saved snippets inside the host application without leaving their workflow. The company also maintains a dedicated AI prompt library feature covering ChatGPT, Claude, Gemini, Perplexity, and Microsoft Copilot.

BlackStack is operated by KERNL LIMITED, incorporated in England and Wales, and was co-founded by Tristan Fonteneau. The product launched in January 2026 and is currently in beta, with versioned releases shipped through May 2026 (v1.0.0 through v1.0.3) and approximately 30+ beta users disclosed. Pricing is seat-based and processed through Polar, with a free tier, a Starter plan at $2.99/month (annual) or $3.49/month (monthly), a Pro plan at beta pricing, and a Team plan with shared workspaces sold via sales contact.

The company targets sales and business development, founders and operators, customer support and success, recruiting and HR, and AI prompt engineers or power users. Go-to-market is product-led via the Chrome Web Store, supplemented by a Team plan sold to groups. The company is bootstrapped with no funding disclosed, headcount under five, and two open engineering roles (Software Engineer - GTM and Software Engineer - Full Stack) listed as expansion signals.

Name

BlackStack

Legal name

KERNL LIMITED

Website

https://blackstack.io

Company type

Private

Founded year

2026

Operating status

Operating

Headcount range

1–10 employees

Short description

BlackStack is a Chrome extension snippet manager that lets knowledge workers store, organize, and deploy reusable text templates and AI prompts across Gmail, Outlook, LinkedIn, Salesforce, HubSpot, and major LLM chat interfaces. It targets sales, support, recruiting, and AI power users via a freemium seat-based subscription model.

Ownership category

akta.pro rank

Headquarters

HQ city

London

HQ country

United Kingdom

HQ region

Europe

Offices1 record

Markets served

GTM type

B2C

Offering type

Software

Cost components

Technology or R&D, Personnel, Marketing or Sales, Operations, Infrastructure

Revenue model

1. Subscription - Seat-based: BlackStack generates revenue through tiered subscription plans billed monthly, quarterly (with 10% discount), or annually (with 20% discount). Subscriptions are seat-based and auto-renew. The company uses Polar for payment processing.

Pricing tiers

Go-to-market motion2 records

Distribution channels3 records

Marketing channels6 records

Core offering

BlackStack is a Chrome extension snippet manager that saves, organizes, and reuses message templates inside web apps where conversations happen, including Gmail, Outlook, LinkedIn, Salesforce, and HubSpot. It features a visual sidebar, text triggers with rich-text formatting preservation, fuzzy search, nested folders, and team workspaces. Delivered as a single unified product consisting of the browser extension and companion web dashboard with Supabase-backed cloud storage and Polar for billing.

Product overview

BlackStack is a single unified product consisting of a Chrome extension snippet manager and associated web dashboard. The core offering is the BlackStack Snippet Manager—a browser-native extension that provides a visual sidebar for saving, organizing, searching, and triggering reusable message templates. The product is designed for high-value human messaging workflows rather than generic text expansion. It supports Gmail, Outlook, LinkedIn, Salesforce, HubSpot, and other web applications. A companion AI Prompt Library feature enables storing prompts for generative AI tools. No separate modules, add-ons, or platform architecture—the product is delivered as one integrated Chrome extension with web dashboard.

Differentiator

Problem solved

Functional benefit

Products and services

• BlackStack Snippet Manager Chrome extension + companion web dashboard that lets users save, organize, search, and deploy reusable message templates directly inside Gmail, Outlook, LinkedIn, Salesforce, HubSpot, Reddit, and other web apps. Features include a visual sidebar, text triggers with rich-text formatting preservation, right-click content capture, nested folders, fuzzy search, and team workspaces. Designed for individual sales, support, recruiting, founder/operator, and AI power-user segments who need instant access to proven human-sounding replies.

Quantifiable outcome

• Save 5-7 hours per week by cutting manual follow-up and message rewriting

Named customers1 record

Segments5 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration7 records

AI capability2 records

Feature5 records

Partnerships

Seven partnerships are on record, tiered core.

• SupabasecoreTechnology or IntegrationSubprocessor for cloud hosting and infrastructure, and database and authentication management. Referenced in Terms of Use as a third-party provider the service relies on.
• PolarcoreTechnology or IntegrationBilling provider handling payment processing. BlackStack does not store credit card details; all payments are securely handled by Polar. Referenced in Terms of Use as the billing provider.
• LinkedIncoreTechnology or IntegrationPrimary integration platform. BlackStack works natively inside LinkedIn for outreach and messaging workflows.
• HubSpotcoreTechnology or IntegrationCRM integration. BlackStack works inside HubSpot for sales and support workflows.
• SalesforcecoreTechnology or IntegrationCRM integration. BlackStack works inside Salesforce for sales and customer management workflows.
• GmailcoreTechnology or IntegrationPrimary email integration. BlackStack works natively inside Gmail for inbox messaging workflows.
• OutlookcoreTechnology or IntegrationEmail integration. BlackStack works inside Outlook for email messaging workflows.

Scale indicators1 record

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• Jasper: Jasper is an established AI content platform with templates and brand-voice features for marketing and sales copy. It serves as a broader incumbent alternative for organizations looking to standardize messaging at scale, competing for the same budget.
• Salesforce: Salesforce provides built-in email templates and quick text features inside its CRM workflows, which BlackStack targets as an integration surface. It competes for the same messaging-efficiency use case as part of a much wider enterprise sales platform.
• HubSpot: HubSpot's CRM includes native email templates and snippets inside its sales and service hubs, which BlackStack explicitly integrates with. It is a broader incumbent that offers overlapping messaging-template functionality within a full CRM suite.

Direct peers

• Magical: Magical is a Chrome extension that lets sales and support professionals save reusable text snippets and auto-fill web forms. It targets the same SDR/AE and support use cases as BlackStack and is listed among BlackStack's published comparison articles.
• TextExpander: TextExpander is a long-established cross-platform text expansion and snippet tool used by professionals to insert reusable text blocks via keyboard shortcuts. It competes directly with BlackStack on snippet organization, triggers, and team/individual plans.
• Text Blaze: Text Blaze is a Chrome-based text expander and snippet manager offering free and team plans with form-like snippet placeholders. BlackStack explicitly publishes comparison content against Text Blaze, confirming it as a head-to-head competitor in browser-native snippet management.
• typedesk: typedesk is a cross-platform text expander with shared team snippet libraries, targeting customer support and sales teams. BlackStack publishes direct comparisons against typedesk, signaling overlapping positioning in the team-snippet-management category.

Emerging players

• Lavender: Lavender is an AI sales email assistant that scores and rewrites outbound emails for SDRs and AEs. It addresses the same 'better outbound messaging' use case as BlackStack but via AI generation/coaching rather than snippet retrieval, making it a partial substitute.
• Copy.ai: Copy.ai is an AI writing platform that generates sales, marketing, and support copy from prompts. It overlaps with BlackStack's AI prompt and messaging use cases but as an AI-generation alternative rather than a snippet-retrieval tool.

Others

• OpenAI (ChatGPT): ChatGPT is a general-purpose generative AI assistant that professionals can use to draft messages and prompts directly. It functions as an enabling alternative for BlackStack's prompt-library and messaging use cases rather than a direct snippet-manager competitor.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks7 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/111283170

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about BlackStack