Plain
Support built for companies whose customers are engineers and whose tickets arrive in Slack
Plain is an API-first customer support platform for B2B software companies, built around the channels technical customers actually use: shared Slack, Microsoft Teams, and Discord channels alongside email, chat, an in-app portal, and forms. It pairs a customer-facing AI agent (Ari) with an internal copilot (Sidekick), integrates natively with Linear, Jira, and PagerDuty, and exposes a GraphQL API deep enough to build your own support surface on top of.
Overview
Plain exists because the standard help desk assumes the wrong customer. When your users are developers at other companies, support does not arrive as a web form; it arrives in a shared Slack Connect channel, a Discord server, or a Teams chat, mixed in with product feedback and a bug report that should really be a Linear issue. Plain treats those channels as first-class inboxes rather than as an integration bolted onto an email tool.
The company was founded in 2020 in London by Simon Rohrbach and Matt Vagni, both from Deliveroo, where Rohrbach ran a 40-person design organisation and Vagni built design systems and internal tooling. It raised a $6M seed co-led by Index Ventures and Connect Ventures in 2022 and a $15M Series A led by Battery Ventures in February 2025, and has since opened a San Francisco office. The customer list is a roll call of developer-tools companies: Vercel, Cursor, n8n, Sourcegraph, Raycast, Clerk, Fly.io, Ashby, Granola, Sanity, and Tinybird among others.
Commercially, Plain does two things worth noting. First, Ari, the customer-facing AI agent, is included on every plan with no per-resolution fee, in a category where $0.75 per resolution is becoming normal. Second, viewer seats are free on every tier, which is the right model for a company where engineers and account managers need to read threads without being support agents. The catch is that the internal copilot, Sidekick, is metered by credits that are consumed by effort rather than by message count, which makes forecasting harder than a flat allowance would.
Best for
B2B software companies, especially developer-tools and infrastructure startups, whose customers are technical, whose support arrives in shared Slack, Teams, or Discord channels, and who have engineering capacity to use an API-first platform properly.
Not the right fit for
- Consumer, ecommerce, or DTC brands; Plain has no meaningful Shopify or order-management story and the channel mix (Slack, Discord, Teams) is wrong for retail customers. Tidio or Crisp fit that shape.
- Non-technical support leads buying without engineering support; the platform's advantage is programmability, and a team that will never touch the GraphQL API is paying for capability it cannot use.
- Solo founders and very small teams watching every dollar; Foundation starts at $35 a month for one seat and each additional seat is another $35, which is more per head than most alternatives.
- Teams that need voice or telephony; there is no phone channel, native dialer, or call-centre functionality of any kind.
- High-volume, low-complexity consumer support where the entire goal is maximum deflection at minimum cost per conversation.
How it works
- 1
You connect the places customers already talk to you: Slack Connect channels, Microsoft Teams, Discord servers, a support mailbox, an in-app chat widget, a customer portal, and embedded forms. Each becomes a channel feeding one workspace, so a bug reported in a shared Slack channel and an email to support@ land in the same queue with the same customer context attached.
- 2
Ari, the customer-facing AI agent, triages what arrives: it answers straightforward questions from the knowledge your team has already written, investigates issues, and escalates when confidence is low or the problem is genuinely complex. Behind the human line, Sidekick acts as the copilot, surfacing account context and drafting responses for an agent to edit, and Insights automatically clusters conversations to surface recurring issues rather than waiting for someone to notice a pattern.
- 3
Engineering escalation is native rather than an afterthought. Workflows route conversations, fire notifications, and create or link Linear and Jira issues and PagerDuty incidents, so the path from 'customer reports it' to 'engineer owns it' does not run through a copy-paste. CRM integrations pull account tier and contract context onto the thread on the Horizon tier and above.
- 4
The layer that distinguishes Plain from every other option here is the API. A public GraphQL API, an MCP server addressable by AI assistants, and a bring-your-own-agent model for connecting your own LLM mean support can be programmatically extended: build a custom in-product support surface, sync your own account data onto customer cards, or plug your own agent into the queue rather than accepting the vendor's.
Feature breakdown
26 features in 5 modulesChannels
The core thesis: B2B customers talk to you where they already work, not on a ticket form.- Slack as a first-class channel
- Shared Slack Connect channels become real support inboxes with assignment, status, and history, rather than an integration that posts notifications into a channel and loses the thread.
- Microsoft Teams
- Teams channels are supported from the Horizon tier, which is the practical requirement for selling into larger, Microsoft-standardised enterprise accounts.
- Discord
- Discord community channels are supported on the Frontier tier, covering the developer-community support model that open-source and infrastructure companies actually run.
- Standard shared-inbox email handling alongside the messaging channels, so the customers who still write to support@ are not second-class.
- In-app chat and portal
- An embeddable chat surface and a customer portal where users see their own conversation history, which matters when your buyer expects an audit trail.
- Forms
- Embedded in-app forms for structured intake, so a bug report arrives with the fields an engineer needs rather than as free text.
AI
Two agents with two roles, and a pricing model that pointedly avoids per-resolution billing.- Ari, the customer-facing agent
- Triages incoming requests, investigates issues, and answers from the knowledge your team has already built. Included on every plan at no per-resolution fee, which is the sharpest commercial contrast in this category.
- Confidence-based escalation
- Ari handles routine triage and straightforward questions but hands off to humans when confidence is low or the issue is complex, rather than forcing a customer through a bot loop.
- Sidekick, the internal copilot
- Surfaces context-aware customer information and drafts responses inside Plain for a human to edit and send. This is what consumes the monthly credit allowance.
- Auto-labelling and urgency detection
- Incoming conversations are classified and prioritised automatically so triage does not depend on someone reading every message in order.
- Thread summaries
- Long escalated threads are condensed before an agent picks them up, which is the difference between a two-minute and a twenty-minute handoff.
- AI suggested responses
- Drafted replies grounded in your own documentation and conversation history, available from the Horizon tier.
- Bring your own agent
- Rather than locking you to Ari, Plain supports connecting your own LLM or agent into the queue, which matters for companies that have already built their own support model.
Workflows and engineering escalation
The path from customer report to engineering ticket, treated as a product feature.- Linear integration
- Create and link Linear issues from a conversation and keep status synchronised, which is the single most-used integration among Plain's developer-tools customer base.
- Jira integration
- Equivalent two-way issue creation and linking for teams standardised on Atlassian rather than Linear.
- PagerDuty and incident routing
- Workflows can escalate a customer report into an on-call incident, so a production problem reported in Slack reaches the person carrying the pager.
- Routing and notification workflows
- Rule-based assignment, alerting, and external system calls, configurable in the UI or driven programmatically through the API.
- SLAs and escalation paths
- Formal response and resolution targets with defined escalation, available from the Horizon tier, which is typically when contractual support commitments start appearing in your own customer agreements.
Developer platform
The reason engineering-led teams pick Plain, and the reason non-technical teams should not.- Public GraphQL API
- A documented GraphQL API covering customers, threads, and workspace objects, positioned as rate-limit-free, so you can build custom support surfaces rather than accepting the vendor's UI.
- MCP server
- A Model Context Protocol endpoint that lets AI assistants query and act on support data, so an internal Claude or similar assistant can work the queue under your permissions.
- Customer cards
- Pull your own product, billing, and usage data onto the customer profile via API, so an agent sees the account's real state instead of asking the customer for their plan.
- Custom workspaces
- Frontier-tier configuration of bespoke workspace structures for companies with multiple products or support organisations.
Knowledge and analytics
Self-service content and the reporting layer that tells you what to write next.- Help Center
- A hosted, public-facing help site included from the Foundation tier, which also feeds Ari's answers.
- Knowledge Base
- Internal and customer-facing knowledge management included on every plan, structured as the training corpus for both AI agents.
- Insights
- Automatic detection of trends and recurring issues across conversations, which converts support volume into a product-feedback signal instead of leaving it as a queue metric.
- Free viewer seats
- Unlimited read-only seats across all tiers, so engineers, account managers, and founders can follow customer threads without occupying a paid seat. Genuinely unusual and genuinely useful.
Use cases
4 documentedDeveloper-tools startup supporting customers in Slack Connect
Twenty enterprise customers each have a shared Slack channel. Requests, bugs, and feature asks are indistinguishable, nothing has an owner, and the only record of a promise made in March is a scrollback nobody can find.
Each Slack channel becomes a real inbox with assignment, status, and SLA tracking; Ari triages the routine questions; bugs become Linear issues from the thread; and Insights shows which product area generates the volume.
Head of developer success at a Series A infrastructure company
Support is five people, but fifteen engineers need to see customer threads. Every per-seat help desk charges for all twenty, and buying read-only access is a recurring budget argument.
Free unlimited viewer seats on every tier mean the whole engineering org can follow customer conversations while only the five agents are billed, which is the cost structure the team actually needs.
Support engineer building a custom in-product help surface
The company wants support embedded natively in its own dashboard, with the customer's real usage and billing state attached to every conversation, not a generic widget iframe.
The GraphQL API plus customer cards let the team build the surface themselves and push their own account data onto every thread, which is not possible on a settings-screen-only help desk.
Startup weighing per-resolution AI costs
The team wants an AI agent handling first-line questions but is looking at $0.75 per resolution elsewhere, which turns a successful deflection programme into a growing monthly bill.
Ari is included on every Plain plan with no per-resolution fee, so deflection volume does not change the invoice; the variable component is Sidekick credits, which meter the internal copilot rather than customer-facing resolutions.
Pricing
from $35/mo (Foundation, 1 seat included; $35 per additional seat)Tiered subscription with a base price that includes a block of seats, per-additional-seat pricing on top, and a monthly Sidekick credit allowance per tier. Ari, the customer-facing AI agent, is included at no per-resolution charge. Monthly or annual billing, with unlimited free viewer seats on every plan.
| Plan | Price | Includes |
|---|---|---|
| Foundation | $35 per month, 1 seat included, $35 per additional seat |
Documentation indicates Foundation is capped at 5 user seats, so a growing support team is pushed up a tier by headcount as well as features. |
| Horizon | $299 per month, 3 seats included, $99 per additional seat |
The jump from $35 to $299 is the steepest step in the category, and the additional-seat price nearly triples from $35 to $99. |
| Frontier | Custom quoted, volume or org-wide |
|
Add-ons
- Additional seats ($35 each on Foundation, $99 each on Horizon): Viewer (read-only) seats are unlimited and free on every plan.
- Startup programme discount (Up to 50% off): Available to eligible early-stage startups, which brings the effective entry price well below the list rate.
Billing notes
- Ari, the customer-facing AI agent, is included on every plan with no per-resolution fee, and Plain's documentation states it is currently free to use across all workspaces. That is the headline commercial difference versus Help Scout's $0.75 per resolution.
- Sidekick credits, which meter the internal AI copilot, are the variable cost: 2,000 per month on Foundation, 15,000 on Horizon, custom on Frontier. Credits are consumed by effort rather than by message count, so the same allowance covers very different amounts of work and monthly usage is harder to forecast than a flat quota.
- Annual billing is available at roughly 10% off, alongside monthly.
- Seat caps apply on top of seat pricing: Foundation is documented at up to 5 user seats and Horizon at up to 10, so a team can be pushed to the next tier by headcount alone.
- Unlimited free viewer seats are a real economic feature, not a footnote; for a company where fifteen engineers need read access, it removes a per-seat cost that every competitor charges.
- The $35 to $299 tier gap deserves scrutiny before signing: Microsoft Teams, SLAs, CRM integrations, and AI suggested responses all sit on the far side of it.
- Prices are as of August 2026 and are quoted in USD.
Value assessment: Plain is not cheap per seat, and it is not trying to be. Foundation at $35 a seat is above Help Scout's $21 annual Standard rate and far above Chatwoot's $19, and Horizon's $99 additional seats are the highest published in this comparison set. What you get for it is a different set of economics: free unlimited viewers, a customer-facing AI agent with no resolution meter, and an API deep enough that engineering can build rather than request. For a fifteen-person B2B software company where five people answer and ten need to read, Plain frequently comes out cheaper in total than a $25-per-seat platform charging for all fifteen plus $0.75 per AI resolution. For a non-technical team of five doing email support, it is simply expensive. The startup programme's 50% discount materially changes the calculation for early-stage companies and is worth asking about before comparing list prices.
Strengths & limitations
Strengths
- Slack, Teams, and Discord are treated as genuine support channels with assignment, status, and SLA tracking, which no general-purpose help desk in this set does properly.
- Ari is included with no per-resolution fee, which means deflection success lowers your cost per conversation instead of inflating the invoice.
- Unlimited free viewer seats let an entire engineering organisation follow customer threads without a per-seat charge, matching how B2B software companies actually work.
- The GraphQL API, MCP server, and bring-your-own-agent model make Plain programmable in a way that lets a team build its own support surface rather than living inside the vendor's UI.
- Native Linear, Jira, and PagerDuty escalation turns the customer-report-to-engineering-ticket path into a workflow rather than a copy-paste.
- Credible customer proof in its target segment: Vercel, Cursor, n8n, Sourcegraph, Raycast, Clerk, Fly.io, and Granola are the exact companies Plain is designed for.
- Well funded and focused: $15M Series A led by Battery Ventures in February 2025 following a $6M Index and Connect seed, with a clear thesis rather than a broadening product.
Limitations
- The $35 to $299 tier jump is severe, and the per-additional-seat price nearly triples across it, so a team crossing from Foundation to Horizon sees a step change rather than a gradient.
- Sidekick credits are metered by effort rather than volume, which makes the variable portion of the bill genuinely hard to forecast month to month.
- No voice or telephony of any kind, and no realistic path to phone support.
- Wrong shape for consumer and ecommerce support: no order-management story, no Shopify depth, and a channel mix aimed at business customers.
- The value is concentrated in the API and the channel model, so a team without engineering involvement pays a premium for capability it will not exercise.
- Younger and smaller than the incumbents in this category, with a shorter track record and a smaller support and documentation operation.
Head-to-head comparisons
3 alternativesPlain vs Help Scout
from $21/user/mo (Standard, billed annually; $25 monthly)Help Scout is the better buy for a non-technical support team doing high-touch email at lower cost per seat, with fifteen years of stability, SOC 2, and HIPAA behind it. Plain is the better buy when your customers are engineers in shared Slack channels, your escalations belong in Linear, and you want an API rather than a settings screen. The AI economics also diverge sharply: Help Scout charges $0.75 per AI resolution while Plain includes Ari at no per-resolution fee.
Full Plain vs Help Scout comparisonPlain vs Crisp
from $45/mo flat (Mini, 4 seats included)Crisp is the cheaper, broader, chat-and-widget-led product with flat workspace pricing and bundled AI credits, aimed at SMB and ecommerce teams. Plain is the narrower, more expensive, developer-focused product with a far stronger API and B2B channel model. If your customers browse a storefront, Crisp; if your customers deploy your SDK and open a Slack Connect channel, Plain, and the price difference will be justified by the escalation workflow alone.
Full Plain vs Crisp comparisonPlain vs Chatwoot
from $0 (Community Edition self-hosted, or cloud Hacker tier); $19/agent/mo for cloud Startups billed annuallyBoth attract technical buyers, but for opposite reasons: Chatwoot's appeal is owning MIT-licensed source you can self-host and modify, while Plain's is a hosted GraphQL API and a channel model built around Slack, Teams, and Discord. Chatwoot's channel mix is consumer web messaging (WhatsApp, Instagram, TikTok) and it is far cheaper per agent; Plain's is business collaboration channels with native Linear and Jira escalation. If your customers message you on WhatsApp, take Chatwoot; if they open a Slack Connect channel and expect a Linear issue back, take Plain.
Full Plain vs Chatwoot comparisonImplementation & onboarding
- Setup time
- A working workspace with Slack and email connected in an afternoon. Getting real value (workflows routing to Linear, customer cards populated from your own API, Ari trained on your documentation, SLAs configured) is more like two to four weeks with engineering involvement.
- Learning curve
- Low for agents, moderate to high for the person configuring it. The API-first design means the best implementations involve writing code, and teams that treat Plain as a point-and-click help desk will under-use it. The 7-day trial is short for a proper technical evaluation, so plan the pilot before starting the clock.
- Onboarding
- Self-serve on Foundation, with Plain's own team assisting on Horizon (including priority Slack support), and a dedicated CSM with white-glove onboarding on Frontier. Eligible early-stage startups can apply to the startup programme for up to 50% off.
- Migration notes
- Historic conversation import runs through the GraphQL API rather than a one-click migrator, so expect to write a script. The larger migration is conceptual: teams moving from an email-only help desk have to decide which Slack channels become real support inboxes and rebuild their knowledge content so Ari can answer from it, which is content and process work rather than data movement.
Platform, API & security
- Platforms
- Web appSlack, Microsoft Teams, and Discord integrationsEmbeddable chat and formsCustomer portalGraphQL APIMCP server
- API
- Public GraphQL API covering customers, threads, and workspace objects, positioned by the vendor as having no rate limits, plus an MCP server that lets AI assistants query and act on support data and a bring-your-own-agent path for connecting your own LLM.
- Compliance
- GDPR handling as a UK-incorporated operator (Not Just Tickets Ltd)Advanced security controls positioned on the Frontier tier; detailed certification evidence is not published on the marketing pages
- Data residency
- Not published on public pages; enquire on the Frontier tier.
- SSO
- SSO and SCIM are Frontier-tier features, not available on Foundation or Horizon.
- Security notes
- Plain describes enterprise-grade security as an engineering principle and reserves advanced security, SSO, and SCIM for the custom-priced Frontier tier. Buyers needing published certification reports should request them directly rather than rely on public pages.
Support & resources
- Channels
- In-product and email supportPriority Slack support on HorizonDedicated CSM on Frontier
- Documentation
- help.plain.com plus developer documentation for the GraphQL API and MCP server; the pricing and credits articles are unusually explicit about how billing works, which is welcome.
- Community
- Strong presence in the developer-tools and B2B SaaS community through a heavily invested content programme; no large public user forum.
Company
- Founded
- 2020
- Headquarters
- London, United Kingdom (with a San Francisco office opened after the 2025 Series A)
- Ownership
- Venture-backed; operated as Not Just Tickets Ltd
- Founders
- Simon Rohrbach, Matt Vagni
- Employees
- Not disclosed; a small team consistent with a recently raised Series A
- Funding
- $21M raised: a $6M seed in 2022 co-led by Index Ventures and Connect Ventures, and a $15M Series A in February 2025 led by Battery Ventures with Index and Connect participating.
Funding history
| Round | Amount | Year | Notes |
|---|---|---|---|
| Seed | $6M | 2022 | Co-led by Index Ventures and Connect Ventures to build an API-first support platform. |
| Series A | $15M | 2025 | Led by Battery Ventures (reported as roughly 14.5M euro and 12M pounds in European coverage); funded a San Francisco office and team expansion. |
Timeline
- 2020Founded in London by Simon Rohrbach and Matt Vagni, both from Deliveroo, where Rohrbach led a 40-person design organisation and Vagni built design systems and internal tooling.
- 2022Raises a $6M seed co-led by Index Ventures and Connect Ventures to build an API-first customer support platform.
- 2024Establishes the collaborative B2B support model, treating shared Slack and Discord channels as first-class support inboxes alongside email.
- 2025Raises a $15M Series A led by Battery Ventures in February, opens a San Francisco office, and grows a customer base concentrated in developer tools: Vercel, Cursor, n8n, Sourcegraph, and Raycast among them.
- 2026Splits AI into two products, Ari for customers and Sidekick for agents, and ships an MCP server plus a bring-your-own-agent model, keeping Ari free of per-resolution charges while competitors move the other way.
Integrations
- Slack and Slack Connect
- Microsoft Teams (Horizon)
- Discord (Frontier)
- Linear
- Jira
- PagerDuty
- CRM integrations (Horizon and above)
- GraphQL API and webhooks
- MCP server
- Bring your own LLM or agent
Frequently asked questions
10 questionsWhat is Plain?
Plain is an API-first customer support platform for B2B software companies. It treats shared Slack, Microsoft Teams, and Discord channels as first-class support inboxes alongside email, chat, a portal, and forms, and pairs a customer-facing AI agent called Ari with an internal copilot called Sidekick. It is built for teams whose customers are technical and whose escalations belong in Linear or Jira.
How much does Plain cost?
Foundation is $35 a month including 1 seat, with additional seats at $35 each. Horizon is $299 a month including 3 seats, with additional seats at $99 each. Frontier is custom-priced. There is a 7-day free trial with no credit card, annual billing saves roughly 10%, and eligible early-stage startups can get up to 50% off through the startup programme.
Does Plain charge per AI resolution?
No, and this is deliberate positioning. Ari, the customer-facing AI agent, is included on every plan with no per-resolution fee, and Plain's documentation states it is currently free to use for all workspaces. The metered component is Sidekick credits, which cover the internal AI copilot: 2,000 a month on Foundation, 15,000 on Horizon, custom on Frontier.
What are Plain's Sidekick credits and how do they work?
Credits meter Sidekick, Plain's internal AI assistant that surfaces context and drafts responses for agents. Each plan includes a monthly allowance that resets at the start of the billing cycle. The important caveat is that credits are consumed by effort rather than by message count, so the same allowance can cover very different amounts of work and the variable part of your bill is harder to forecast than a flat quota would be.
Can Plain handle support in Slack?
Yes, and it is the main reason to choose it. Shared Slack Connect channels become genuine support inboxes with assignment, status, history, and SLA tracking, rather than an integration that posts notifications and loses the thread. Microsoft Teams is supported from the Horizon tier and Discord from Frontier.
Are viewer seats really free in Plain?
Yes. Read-only viewer seats are unlimited and free across all tiers. For a B2B software company where five people answer tickets but fifteen engineers need to follow customer threads, that removes a per-seat cost every competitor in this category charges, and it often makes Plain cheaper in total despite a higher headline seat price.
Who uses Plain?
Plain's customer base is concentrated in developer tools and infrastructure, including Vercel, Cursor, n8n, Sourcegraph, Raycast, Clerk, Fly.io, Ashby, Granola, Sanity, and Tinybird. If your company looks like those, Plain was designed for you; if you sell to consumers, it was not.
Does Plain have an API?
Yes, and it is central rather than peripheral. Plain exposes a public GraphQL API covering customers, threads, and workspace objects (positioned as rate-limit-free), an MCP server so AI assistants can query and act on support data, customer cards for pushing your own product and billing data onto profiles, and a bring-your-own-agent model for connecting your own LLM.
Does Plain support phone or voice?
No. There is no telephony, dialer, or call-centre capability, and no indication one is planned. Plain's channel model is text-based and asynchronous by design, aimed at B2B customers who write rather than call. Teams that need voice as a real channel should look elsewhere or run a separate phone system.
Is Plain worth it for a small startup?
It depends on who your customers are. For a five-person developer-tools company whose users file issues in Slack and whose engineers all need read access, Foundation at $35 plus free viewer seats plus a startup discount of up to 50% is very reasonable and the Linear escalation alone justifies it. For a five-person team doing ordinary email support for non-technical customers, $35 per seat with a 7-day trial and no free plan is poor value against Help Scout, Crisp, or Chatwoot.
Editorial verdict
Plain is the sharpest product in this category for a specific and growing shape of company: B2B software businesses whose customers are engineers, whose support lands in Slack, and whose escalations end in Linear. The channel model is right, the free viewer seats reflect how those teams actually operate, the GraphQL API and MCP server make it programmable rather than merely configurable, and including Ari with no per-resolution charge is a genuinely pro-customer stance while the rest of the category moves toward metering. The reservations are the brutal $35 to $299 tier gap, Sidekick credits that are hard to forecast because they meter effort rather than volume, no voice channel, and no free plan. Buy Plain if your customers write to you in a shared Slack channel. If they do not, almost everything here will serve you better and cost less.
Written by the SaaSTracker editorial team. Awards, when shown, are judged against the published criteria in our methodology.