When the free Stalwart edition is enough and when Enterprise is worth paying for
Community is enough for most self-hosted mail teams that do not need a vendor support contract. Stalwart's Community edition is free, carries no mailbox limit and has no license cost, so a team that can run its own mail stack, monitor it and handle upgrades in-house has no licensing reason to pay. Enterprise is a per-mailbox subscription whose features are activated by a license key, and the features it unlocks are the decision point. Before deciding, list the specific Enterprise features your environment depends on and confirm in writing with Stalwart which of them are included at your tier, because this comparison does not treat any Enterprise feature beyond those named in the published pricing as established.
The conditions that favor Enterprise are a mailbox count inside the published tiers and a need for contracted support. Per the Stalwart pricing page, Enterprise costs 2.00 euros or 2.40 US dollars per mailbox per year for 25 to 499 mailboxes, with a 25-mailbox minimum, so a 10-mailbox team pays nothing to stay on Community but cannot buy the 25-mailbox entry tier at a lower count. Premium Support starts at 150 mailboxes, with an initial response within 48 business hours, while smaller Enterprise customers use community support. If your organization needs a named support channel with a response commitment below 150 mailboxes, you should ask Stalwart directly what it will contract for at your size. Also note that cancelling Enterprise reverts to Community without data loss, which lowers the risk of trying a paid tier.
Which Stalwart capabilities sit in Community and which need the Enterprise key
This table maps the capabilities Stalwart's README documents to the two editions. The public facts give no per-feature split, so most capability rows show what is documented and what to confirm. The license, support and downgrade rows are the certain differences, so start there, then request the written feature matrix before sizing a purchase.
| Capability | Community edition | Enterprise key |
|---|---|---|
| Mail protocols (JMAP, IMAP, POP3, SMTP) | Documented in the README. No edition split in the public facts. | Documented in the README. Confirm whether any protocol is gated by the key. |
| Calendar and contacts (CalDAV, CardDAV, WebDAV) | Documented in the README. No edition split in the public facts. | Documented in the README. Confirm whether any of these is gated by the key. |
| Pluggable storage backends | Documented in the README, including PostgreSQL, MySQL, SQLite and S3-compatible storage. No split published. | Same backend list documented. Confirm backend support by edition before choosing storage. |
| Built-in spam filtering | Documented in the README, covering DNS blocklists, greylisting and Pyzor. No split published. | Documented in the README, including LLM-driven analysis. Confirm which filter features need the key. |
| Clustering (peer-to-peer, Kafka, Redpanda, NATS, Redis) | Documented in the README. No split published. Confirm before relying on it for high availability. | Documented in the README. Confirm whether clustering options need the Enterprise key. |
| License and activation | Free, with no mailbox limit, according to the pricing page. | Per-mailbox subscription. Features are activated by a license key. |
| Support | Community support for smaller Enterprise customers, per the pricing page. | Premium Support from 150 mailboxes, with an initial response within 48 business hours. |
| Downgrade from Enterprise | Reverts here after cancellation, without data loss, per the pricing page. | Cancelling the subscription reverts the server to Community. |
What the free AGPL Community edition covers for a self-hosted mail team
Stalwart Community is free to run, with no mailbox limit, and it is licensed under the AGPL-3.0. For a self-hosting mail team, the server itself carries no per-mailbox charge. The protocol surface includes JMAP, IMAP, POP3, SMTP, CalDAV, CardDAV and WebDAV, so mail, calendar, contacts and file access can run from one server. Storage is also pluggable. The README lists RocksDB, FoundationDB, PostgreSQL, MySQL, SQLite, S3-compatible storage, Azure and Redis, so the backend is an architecture decision made at installation that is costly to reverse later. Ask Stalwart which backends and clustering options, whether peer-to-peer or through Kafka, Redpanda, NATS or Redis, are available under Community and which depend on the Enterprise license key. Get that answer in writing before you design around it.
The AGPL matters most once you change the software. It is a copyleft license, and its network clause is the part mail teams most often miss. If you modify Stalwart and let users interact with that modified version over a network, the license can require you to offer those users the corresponding source of your changes. Running an unmodified build for your own staff is a different situation from patching the spam pipeline, adding a connector or shipping a branded webmail front end. Because Stalwart is dual-licensed, the proprietary Stalwart Enterprise License is the commercial route if your changes cannot be published. Have counsel review AGPL obligations for your specific use, including hosted services for customers, internal forks and custom code, before the first production deployment. The Stalwart repository is the place to check the license file and current feature notes.
How licensing, license keys and support differ between the two editions
Stalwart ships one codebase under two sets of terms, so the choice between editions is mostly a question of licensing, activation and support rather than features alone. The cards below cover each term in turn and name the condition under which it changes a decision.
AGPL-3.0 Community license
The Community edition is licensed under the AGPL-3.0, which is the license most relevant to teams that run Stalwart as a network service. Under the AGPL, if you modify Stalwart and offer it to users over a network, you must make your modified source available to those users. Teams that change the server code, or embed it in a hosted offering, should have counsel confirm how the obligation applies to their setup before rollout.
Proprietary Enterprise License
Stalwart is dual-licensed, so commercial use can fall under the proprietary Stalwart Enterprise License instead of the AGPL. This matters when your legal team does not want AGPL source-sharing obligations on internal modifications or hosted services. Ask Stalwart Labs which license terms apply to your deployment model, and confirm in writing whether the Enterprise license covers your planned use before you assume it does.
License key activates Enterprise features
Enterprise features are not separate binaries. They are switched on by a license key applied to the same Stalwart installation, billed per mailbox as a subscription. Platform teams should plan the key rollout as a change to the running server, record who holds the key, and check how renewals and mailbox counts are reported before the first production cutover.
Reversion to Community without data loss
Cancelling an Enterprise subscription reverts the server to the Community edition without data loss, according to Stalwart's pricing page. This is the main exit path if budgets change. It does not remove the features you configured, so confirm which Enterprise-only settings stop working after reversion and plan a configuration review as part of any downgrade.
Community support versus Premium Support
Smaller Enterprise customers rely on community support, while Premium Support is included from 150 mailboxes, with an initial response within 48 business hours. If your mail flow is business critical and your mailbox count sits below that threshold, ask whether Premium Support can be bought separately and what the response commitment would be in writing. Community channels do not carry a contractual response time.
Published per-mailbox Enterprise prices and the 25-mailbox minimum
The published Enterprise rate is 2.00 euros or 2.40 US dollars per mailbox per year for 25 to 499 mailboxes. Per the Stalwart pricing page, the rate falls to 1.04 euros per mailbox from 10,000 mailboxes, and quotes are issued for deployments above 100,000 mailboxes. The subscription carries a 25-mailbox minimum, so a team with fewer than 25 mailboxes cannot buy Enterprise at the published rate and should plan on Community, which has no mailbox limit. Count mailboxes the way the vendor does before you budget, including shared, role and service accounts if your license terms treat them as mailboxes.
Because the price is per mailbox per year, the annual figure is a recurring cost that scales with headcount and with any growth in shared or service mailboxes. The license key activates Enterprise features, and cancelling reverts the server to Community without data loss, so the subscription is a recurring line item rather than a one-time purchase. Ask the vendor how mailbox counts are measured, whether the tier applies to the whole deployment at once, and how a mid-term increase is billed. Also confirm whether VAT or sales tax applies and which currency your invoice will use.
Before you commit, reconfirm every figure above on the Stalwart pricing page, because tiers and currency rates can change. Build the budget from the tier that matches your current mailbox count and the count you expect in 12 months. Get the quote in writing with the tier, currency, billing period and the mailbox definition stated, so your finance team can compare it with the cost of running Community and staffing support yourself.
What each edition costs and what drives the Enterprise total
This table separates the license cost of Community from the per-mailbox Enterprise subscription and the operating effort both editions share. Read the Enterprise row against your mailbox count, because the published tier price per mailbox drives most of the license line.
| Cost component | Community edition | Enterprise edition |
|---|---|---|
| License fee | None. The AGPL Community edition is free with no mailbox limit, according to the Stalwart pricing page. | Per-mailbox annual subscription, activated by a license key. Published prices are 2.00 euros or 2.40 US dollars per mailbox per year for 25 to 499 mailboxes, per the Stalwart pricing page. |
| Minimum commitment | No minimum mailbox count. | 25-mailbox minimum. Quotes are required above 100,000 mailboxes, per the Stalwart pricing page. |
| Volume tier effect | Not applicable. | The published rate falls to 1.04 euros per mailbox from 10,000 mailboxes, per the Stalwart pricing page. Confirm which tier applies to your count and currency. |
| Support | Community support only. | Premium Support is included from 150 mailboxes, with an initial response within 48 business hours. Smaller Enterprise customers use community support, per the Stalwart pricing page. |
| Internal operating effort | Your team runs installation, DNS, TLS, backups, storage backend and upgrades. Effort is the same as Enterprise for the base server. | Same internal effort as Community, plus the work of applying and renewing the license key and tracking the subscription term. |
| Reversion and exit | Not applicable. | Cancelling reverts to Community without data loss, per the Stalwart pricing page. Confirm the notice period and billing terms in writing. |
| What raises total cost | Storage backend choices, clustering infrastructure and staff time for monitoring and incident response. | Mailbox growth, a move into a higher-cost tier, Premium Support eligibility and currency exchange on the quoted amount. |
| What to ask for in a quote | Confirmation that no license is required for your planned deployment. | Mailbox count, currency, subscription term, support tier, tier breakpoints applied and whether taxes or fees are itemized. |
Moving from Community to Enterprise, and back, without losing mail
This sequence confirms eligibility, activates Enterprise features with a license key, checks that they work, and sets a support tier, so the team knows what changed and how to return to Community if needed.
Confirm the mailbox count against the minimum
The mail administrator counts the mailboxes that will be active on the Stalwart server and compares the total with the 25-mailbox minimum for Enterprise. Stalwart's pricing page sets Enterprise as a per-mailbox subscription with that floor, so a count below 25 means the Community edition remains the only option until the count changes. Record the number, the date it was taken, and the name of the person who approved the license purchase. The output is a signed-off mailbox count that goes into the quote request.
Request a quote from the written mailbox count
The buyer asks Stalwart for a quote based on the confirmed mailbox count and the current tier. The published per-mailbox prices depend on band, and quotes above 100,000 mailboxes are handled separately, so the request should state the exact number and the expected growth over the subscription term. Ask the vendor to confirm which features the license key activates, which support tier applies, and whether any renewal terms change the price. The output is a written quote that matches the mailbox count from the previous step.
Obtain and apply the license key
After purchase, the administrator receives the Enterprise license key and applies it to the existing Stalwart installation. Take a configuration and data backup before the change, and record the running version so the rollback target is known. Confirm the key is entered in the location documented for the installed release, since Stalwart's documentation governs the exact setting. The output is a restarted server that reports the license as active, with a dated backup stored outside the mail host.
Verify that Enterprise features activate
The team tests each Enterprise feature it depends on in a staging copy first, then in production during a planned window. Check the features the vendor lists as license-gated, and confirm that each one responds as expected for a test mailbox. Compare the mail flow, authentication, and client access against the pre-change baseline so no protocol or mailbox behaves differently. The output is a short test record listing each feature, the result, and who signed off.
Confirm Premium Support eligibility
Stalwart's pricing page states that Premium Support is included from 150 mailboxes, with an initial response within 48 business hours, while smaller Enterprise customers use community support. The team compares its mailbox count with that threshold and checks the support terms in its order paperwork. If the count sits near 150, ask the vendor in writing how support is assigned when mailboxes are added or removed mid-term. The output is a documented support tier and a named escalation contact for mail incidents.
Document feature dependencies before any downgrade
Before the team plans a return to Community, it lists every Enterprise feature in use and any configuration, integration, or client setting that depends on it. Stalwart's pricing page says cancelling reverts the server to Community without data loss, but a feature-dependent setting may stop working even when the mail itself is preserved. Ask the vendor which settings become inactive after reversion. The output is a dependency register that the team can check against the staging test.
Test the reversion to Community in staging
The team runs the downgrade on the staging copy, using a backup taken from production, and compares message counts, folder structures, calendars, contacts, and authentication results with the pre-test baseline. It also checks the features listed in the dependency register and records any that stop working. The reverted staging server must pass the same checks before production is touched. The output is a signed reversion test record that states whether mail survived intact and what must change before production cancellation.
Schedule production reversion only after a passing test
If the staging test passes and the business still wants to leave Enterprise, the team schedules the production change in a maintenance window with a fresh backup and a named rollback owner. It cancels the subscription only after the Community configuration is confirmed working on the production host. The team keeps the Enterprise key and backup for a period set by its own retention policy. The output is a completed change record showing the server runs Community with mail intact.
Questions buyers ask before choosing Stalwart Enterprise
What does Stalwart Enterprise cost for my number of mailboxes?
Enterprise is priced per mailbox per year, and the published rate depends on how many mailboxes you run. The Stalwart pricing page lists 2.00 euros or 2.40 US dollars per mailbox per year for 25 to 499 mailboxes, falling to 1.04 euros from 10,000 mailboxes, with a 25-mailbox minimum and quotes for deployments above 100,000 mailboxes. Multiply your mailbox count by the tier rate to estimate the annual subscription, then confirm currency, tax and billing terms with Stalwart. The subscription is the recurring cost. Your own staff time, DNS work, storage and any implementation services are separate costs that do not appear on the price list.
Can Stalwart Community run production mail without a license?
Yes, the Community edition is free and carries no mailbox limit, so it can serve production mail. Its license is AGPL-3.0, which governs how you may modify and distribute the software. What Community does not include is the set of features activated by an Enterprise license key. Before you rely on Community for a regulated workload, list the Enterprise features you need, check them against the current Stalwart pricing page, and confirm with Stalwart which support channels apply to your mailbox count. Cancelling an Enterprise subscription reverts the server to Community without data loss, according to the same page.
When does Premium Support apply to Stalwart Enterprise?
Premium Support is included with Enterprise from 150 mailboxes, and the Stalwart pricing page states an initial response within 48 business hours. Smaller Enterprise customers use community support. The 48 business-hour figure is a first response target, not a fix time, so it does not tell you how long an outage will last. If mail uptime is a contractual requirement, ask Stalwart for the written support terms, escalation path and any service levels in your quote, and decide whether your internal on-call team can cover the gap in the meantime.
How long does migration and license activation take?
The page does not publish a duration, so treat any figure you hear as something to verify. Activating a license key is a configuration step, while migration depends on mailbox count, data volume, the source server (for example, a Postfix and Dovecot stack or another suite), client reconnection plans and DNS cutover windows. Ask Stalwart and any implementation partner for a written plan that lists each phase, the test mailboxes used for validation and the rollback steps. A fixed-scope written plan makes the timeline auditable before work starts.
What skills and infrastructure does my team need to run Stalwart?
Your team needs working knowledge of SMTP, IMAP and JMAP clients, DNS records for mail (MX, SPF, DKIM, DMARC and PTR), TLS certificate handling and backup and restore procedures. You also choose a storage backend. The README lists RocksDB, FoundationDB, PostgreSQL, MySQL, SQLite, S3-compatible storage, Azure and Redis, and the right choice depends on your existing database operations, backup tooling and whether you plan to cluster. Clustering options include peer-to-peer coordination or Kafka, Redpanda, NATS or Redis. Confirm each choice against Stalwart's current documentation before you commit to a design.
Should we switch to Stalwart ourselves or hire an implementation partner?
A team with in-house mail operations experience and a clear test plan can often run the switch internally, while a team new to mail server operations usually benefits from outside help. DeployOpen plans, implements, migrates, hardens, backs up and documents self-hosted platforms in your own infrastructure, typically under a fixed scope agreed in writing before work starts. DeployOpen does not publish a price list, so ask for a quote based on your written scope, mailbox count, storage design and cutover requirements. Whichever route you choose, keep ownership of DNS, certificates and the final cutover decision in-house.
What would an illustrative 300-mailbox Enterprise subscription look like?
Illustrative only: at 300 mailboxes, the 25 to 499 tier applies, so the list rate of 2.40 US dollars per mailbox per year would work out to 720 US dollars per year, or 2.00 euros per mailbox per year for 600 euros. Premium Support would apply under the published 150-mailbox threshold. Real quotes depend on terms and currency at the time you buy, so request the current pricing from Stalwart. Your total cost also includes internal staff time, storage, backups and any implementation scope, none of which the subscription covers.
When the Enterprise subscription is worth its per-mailbox cost
The Enterprise subscription pays off when the cost of not having a vendor support path is higher than the license fee. Regulated teams are the clearest case: if your change control or third-party risk process expects a named supplier to answer for the mail platform, Community support alone may not satisfy that expectation. Per the Stalwart pricing page, Enterprise is priced per mailbox per year at 2.00 euros or 2.40 US dollars for 25 to 499 mailboxes, with a 25-mailbox minimum. Before you commit, confirm with Stalwart what response commitments apply at your mailbox count, and whether the contract terms meet your vendor risk requirements. Ask the same questions of the Enterprise license key scope, since a key controls which features are activated.
The second condition is size. Stalwart includes Premium Support from 150 mailboxes, with an initial response within 48 business hours, while smaller Enterprise customers use community support. If you sit at or above that threshold and your mail service is business critical, the support tier is a concrete reason to pay. Below it, you are buying license-gated features and a support channel that is not Premium. Also consider the features behind the key. If your team needs capabilities that are only activated by a license, such as those your audit or integration requirements depend on, the subscription is a feature decision as much as a support decision. Cancelling reverts to Community without data loss, which lowers the cost of trying Enterprise, but you should still plan what happens to any workflow that depends on a gated feature.
Small teams with strong internal mail skills can reasonably run Community indefinitely. Community is free with no mailbox limit, and the AGPL-3.0 terms cover the core server. The trade-off is that your team carries the diagnosis, patching, and clustering decisions without a contracted vendor, and that you accept community support for anything that breaks. Organizations that choose the paid tier give up some of that independence and accept an annual per-mailbox cost that recurs for as long as they remain subscribed. Whichever path you choose, write down the trigger that would make you revisit it, such as a new compliance requirement, a growth in mailbox count past 150, or a feature you need that sits behind the key.
How DeployOpen delivers and supports either Stalwart edition
DeployOpen plans, implements, integrates, hardens, documents and supports self-hosted open-source platforms inside your own cloud accounts, data centers or air-gapped networks. The same method applies whether you run Stalwart Community or Enterprise, with the license decision, key handling and support route agreed in writing before any build work starts.
How we scope
- We confirm mailbox count, domains, protocols and client mix before choosing an edition.
- The written scope states whether Stalwart Community or Enterprise is in scope and why.
- Engagements are fixed-scope, with deliverables and timelines agreed in writing before work starts.
How we build
- We deploy Stalwart inside your infrastructure, with storage backend and clustering choices documented.
- Enterprise license keys are installed and verified as part of the build, not left as an open item.
- Spam filtering, TLS, DNS records and client connections are configured and tested against the scope.
How we hand over
- You receive architecture notes, configuration documentation and runbooks for your own operators.
- Backup and restore procedures are tested, so recovery is shown to work before handover.
- Downgrading from Enterprise to Community is documented, including what changes and what stays intact.
How we support
- Ongoing support, upgrades and continuous testing are available as retainers after handover.
- Upgrades to new Stalwart releases are planned, tested in staging and documented before rollout.
- Confirm with Stalwart which support tier applies to your mailbox count before relying on it.
