Hermers is not a client. It is the programmatic substrate beneath every client ; speaking IMAP, SMTP, JMAP, gRPC, REST, and MCP simultaneously against a single, authoritative source of truth.
Whether you're wiring up a legacy email client, building an AI agent, or shipping a real-time dashboard ; Hermers speaks your protocol. Every access mode reads from and writes to the same authoritative data layer.
Standard JSON over HTTPS. Full CRUD for every resource. Cursor-paginated responses. Works with any HTTP client in any language.
Persistent HTTP/2 connections for real-time notification and bulk operations. Protocol Buffers for efficient binary transport.
Native MCP server via stdio transport. LLMs call structured tools without touching raw message content. Scoped keys enforce exactly what each agent can see.
Connect the tools your team already uses. Apple Calendar, Thunderbird, Outlook, GNOME ; they all speak the protocols Hermers speaks natively.
Hermers speaks every major open standard simultaneously. Legacy clients connect to native IMAP and SMTP with zero configuration. Modern systems use JMAP or gRPC for structured, high-throughput access. AI agents use MCP.
State divergence is resolved with a single integer comparison. No full mailbox rescans, no wasted bandwidth. Clients compute their differential against the current modseq and request only what changed.
A monotonically increasing per-mailbox modification sequence drives incremental synchronization for both IMAP CONDSTORE and JMAP changes ; in a single round-trip.
Every downstream event ; webhook, gRPC push, Kafka relay ; is written atomically with its originating state change. If the transaction rolls back, the event is never published.
Tenant boundaries are enforced by strict data isolation policies ; not middleware, not application logic. An unset session variable returns zero rows by design. There is no application path to cross-tenant data.
A personal tenant is provisioned automatically at signup. Team tenants own multiple users, shared domains, and billing. Every resource is scoped and isolated at the row level.
Message bodies, attachments, and calendar objects are stored as SHA-256 hashed blobs via OpenDAL. Swap backends ; in any environment ; without touching application code or migrating data.
Install the Hermers CLI, initialize a tenant, and start sending and receiving mail with your first API key. No credit card required for the free tier.
Every tier runs on the same infrastructure. Enterprise overrides are provisioned instantly ; no redeployment, no support ticket required.
| Feature | Free | Starter$4 / mo | Pro$29 / mo | Business$249 / mo | EnterpriseCustom |
|---|---|---|---|---|---|
| Email Accounts (Mailboxes) | 1 | 5 | 25 | 150 | Unlimited |
| API Requests / min | 60 | 300 | 1,000 | 5,000 | Unlimited |
| Sends / day | 0 | 1,000 | 10,000 | 100,000 | Custom |
| Storage | 1 GB | 10 GB | 50 GB | 500 GB | Custom |
| Access Modes | REST + Native | REST + gRPC + Native | All modes | All modes | All modes |
| Webhooks | - | 5 endpoints | 20 endpoints | Unlimited | Unlimited |
| MCP Access | - | - | ✓ | ✓ | ✓ |
| SLA | Best effort | 99.9% | 99.95% | 99.99% | Custom |
All tiers include: tenant isolation, Argon2id auth, TOTP 2FA, DKIM/DMARC/SPF, MTA-STS enforcement, delta-sync, and the full protocol suite.
Deploy a programmatic mailbox in under five minutes. IMAP, SMTP, JMAP, REST, and MCP available immediately. No credit card required.
Initialize Tenant →Unlimited sends, bespoke storage limits, quota overrides provisioned without redeployment, and direct engineering support from day one.
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