Plain is an AI-native B2B customer support platform that turns Slack Connect, Microsoft Teams, Discord, email, and a headless portal into a single shared inbox — with an in-house AI agent called Ari that auto-resolves frontline tickets and a developer-grade GraphQL API underneath. We rate it 85/100 — the best pick today for B2B SaaS teams whose customers already live in Slack and who are tired of bending Zendesk into shapes it was never designed for.

What is Plain?

Plain is a B2B-only support platform founded in 2020 by Simon Rohrbach (CEO, ex-Director of Design at Deliveroo) and Matt Vagni (CTO, ex-Lyst and Deliveroo). The company is headquartered in London and raised a $15M Series A on February 14, 2025, led by Battery Ventures with continued participation from Index Ventures and Connect Ventures, on top of a $6M seed in 2022. The platform now serves customers including Vercel, Cursor, n8n, Ashby, Raycast, Stytch, Sanity, and Laravel.

The problem Plain solves is specific: legacy support tools (Zendesk, Intercom, Freshdesk) were designed for high-volume B2C ticket queues where customers are anonymous. B2B SaaS support is the opposite — a smaller number of named accounts, conversations that bounce between Slack, email, and the founder's DMs, and an expectation that the engineer who shipped the bug is the one who fixes it. Plain treats Slack Connect, MS Teams, and Discord as first-class channels, not afterthoughts — every Slack message flows into the support queue with full customer context, and replies from Plain show up natively as Slack messages.

Plain — the AI support stack built for B2B — Plain's marketing splash: a composable AI support stack for B2B teams, no-code or all-code.

Key Features of Plain

Ari, the customer-facing AI agent: Ari talks to customers in your help center, Slack, Discord, and Teams, resolves Tier 1 questions against your knowledge base, and escalates to humans with the full conversation context attached — no separate handoff ticket.
Sidekick, the internal AI copilot: Drafts replies, summarizes long threads, suggests labels and priorities, and surfaces similar past tickets so a new support agent can ramp faster.
Native Slack Connect, Teams, and Discord channels: Bidirectional sync — customers stay in their preferred chat tool, your team works inside Plain, and nothing gets lost in a forwarding chain. Discourse and a headless portal are also first-class channels.
GraphQL API and webhooks: A public GraphQL API plus webhooks let engineering teams pipe customer context (subscription tier, last deploy, feature flags) into the side panel of every ticket and trigger workflows externally.
Customer tiers and SLAs: Built-in account hierarchy means a $200K/year customer's ticket can route differently from a free-tier user's, with automatic SLA timers and breach alerts — something Zendesk requires the Enterprise plan and a consultant to configure.
Insights: AI-generated weekly digests of conversation themes, drift, and unresolved customer pain — flagged at the account level, not just topic level.
Bring-your-own AI on the Frontier plan: Plug in your own model, prompts, and retrieval pipeline. Useful for teams with strict residency or vendor-lock concerns.
14-day free trial, no credit card: The trial includes the full Foundation feature set so you can pilot it on a real Slack channel before committing.

Plain product interface showing the unified support inbox — Plain's unified inbox: Slack, email, Discord, and portal threads in one queue with native customer context.

What Users Say About Plain

Public sentiment skews positive but specific. On G2, the most upvoted phrase from reviewers is that Plain is “refreshingly straightforward without sacrificing power” and “the first support platform I've ever been excited to log into” — a contrast with the spreadsheet-of-tabs feeling reviewers consistently associate with Zendesk and Intercom. The Plain customers page lists named usage at Vercel, Cursor, n8n, Stytch, Ashby, and Raycast.

The honest criticisms are equally specific. On G2 and developer forums, the recurring complaint is that several methods are restricted to Plain's internal API explorer and don't function in external integrations — fine for a no-code workflow, frustrating if you're building a custom dashboard. A second complaint is that the per-seat pricing scales painfully for support orgs with many part-time triagers; teams over 50 seats consistently push toward the Frontier plan, where pricing becomes negotiated. Finally, Plain is unapologetically B2B — if you run a high-volume B2C support queue with a million tickets a month, it isn't built for you and the team will tell you so.

Plain Pricing

Plain prices per seat with no separate AI usage fees and a flat 14-day free trial. Plans as of May 2026:

Plan	Price	Key Limits and Features
Foundation	$35/seat/month	Unified inbox, native Slack/Teams/Discord/email, GraphQL API, webhooks, customer tiers, basic Insights, Sidekick AI assist for agents.
Horizon	$89/seat/month	Everything in Foundation plus Ari customer-facing AI agent, advanced SLAs, audit log, SAML SSO, custom workflows, advanced Insights.
Frontier	Custom (contact sales)	Bring-your-own AI agent and models, custom Sidekick, dedicated support, single-tenant deployment, custom data residency.

Bundled package plans — essentially small-team pre-pays — are also available at $199/month, $269/month, and $299/month for fixed seat counts.

Who Should Use Plain?

Best for: B2B SaaS companies with 5–200 customers using Slack Connect or Discord as a primary channel; developer-tools and infrastructure companies whose engineers triage tickets directly; teams who want a public API to wire customer context into their support workflow rather than a closed black box.

Not ideal for: High-volume B2C support (e-commerce returns, consumer apps with a million tickets/month — use Zendesk or Front instead); solo founders who need free forever (the 14-day trial expires); regulated workloads requiring on-prem (Frontier offers single-tenant cloud, but not self-hosted).

Pros and Cons

Pros:

Native Slack Connect support is genuinely first-class, not a glued-on integration — confirmed across multiple G2 reviews and the customer roster.
Transparent flat per-seat pricing with no AI usage surcharges — a deliberate contrast with Zendesk's variable AI add-ons.
Public GraphQL API and webhooks make it possible to build custom side-panel context that legacy support tools require Enterprise tiers and consultants for.
Modern UI praised by reviewers as fast and uncluttered — Plain's founders previously led design at Deliveroo and it shows.
Used in production by demanding developer-tools companies (Vercel, Cursor, Sanity, Stytch, Raycast), which is a meaningful trust signal for technical buyers.

Cons:

Some GraphQL methods are restricted to Plain's internal explorer — a recurring developer complaint when building external integrations.
Per-seat pricing punishes large support orgs with many part-time triagers; cost crosses Zendesk territory at 50+ seats.
No free tier, only a 14-day trial — not a fit for hobby projects or pre-revenue founders.
B2B-only by design — not the right tool if your support queue is high-volume consumer.

Alternatives to Plain

Zendesk remains the default for B2C and large support orgs, with the broadest integration ecosystem but a UI universally described as bloated. Intercom leads on outbound messaging and Fin AI but is significantly more expensive at scale. Front is the closest direct competitor for shared-inbox B2B teams; Plain wins on native Slack Connect and AI-native design, Front wins on email-first workflows. Self-hosted alternatives like Mattermost or community projects like Chatwoot give up the AI agent and B2B-specific features in exchange for full data control.

Verdict: Is Plain Worth It?

If you run a B2B SaaS company — especially developer tools, infrastructure, or anything where customers expect to message your team in Slack — Plain is the strongest entrant in 2026. The Foundation plan at $35/seat undercuts Zendesk Suite Professional ($115/agent) while delivering the B2B-specific features (account tiers, native Slack Connect, GraphQL API) that Zendesk gates behind Enterprise pricing. The recurring developer-experience complaints around restricted API methods are real and worth verifying against your specific workflow during the 14-day trial. We rate it 85/100 — docked for the API rough edges and the lack of a free tier, but the AI-native, B2B-native design is a step ahead of every legacy support tool we've reviewed.

Frequently Asked Questions

Is Plain free?: No — Plain has a 14-day free trial that includes the full Foundation feature set, but no permanent free tier. Paid plans start at $35/seat/month.
What channels does Plain support?: Slack and Slack Connect, Microsoft Teams, Discord, Discourse, email, and a headless portal you can embed in your own product. All are treated as first-class native channels, not third-party integrations.
How does Plain compare to Zendesk?: Plain is purpose-built for B2B SaaS with native Slack/Teams/Discord and a public GraphQL API; Zendesk is a general-purpose helpdesk that scales to high-volume B2C. Plain Foundation ($35/seat) is cheaper than Zendesk Suite Professional ($115/agent), but Zendesk has a much wider integration ecosystem.
Does Plain have an AI agent?: Yes. Ari is Plain's customer-facing AI agent (available on the Horizon plan) and Sidekick is an internal AI copilot for support agents. There are no separate AI usage fees — AI is included in the per-seat price.
Is Plain open source?: No, Plain is a closed-source SaaS product. It does, however, expose a public GraphQL API and webhooks for custom integrations.
Who uses Plain?: Named customers include Vercel, Cursor, n8n, Stytch, Sanity, Ashby, Raycast, and Laravel — a roster heavily skewed toward developer-tools and infrastructure companies.

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