free-plan-node-capability

This is a receipt

The frontmatter below is the record: id, kind, measured_on, stale_when, values. The file in the repository is the authority. This page renders it.

id: free-plan-node-capability
kind: platform-limit
measured_on: 2026-08-03
stale_when: >
  Cloudflare changes free-plan Email Sending behaviour, extends sending beyond verified
  destination addresses on free, or changes the wording of the verified-destination error
values:
  freeplan.inbound_to_worker: 1
  freeplan.send_to_verified_destination: 1
  freeplan.send_to_arbitrary_recipient: 0
  freeplan.send_error_names_the_plan: 0

Measured: live test on a Workers Free account, 3 August 2026. A probe Worker with an email() handler, a D1 binding and a send_email binding, deployed to mailda-freeplan-probe, with one Email Routing rule pointing mailda-test@straits-ai.com at it. All test resources removed afterwards.

Inbound works, end to end, at zero cost

A real message sent from Gmail arrived and was persisted:

{ "from_addr": "swmengappdev@gmail.com",
  "to_addr":   "mailda-test@straits-ai.com",
  "subject":   "Testing 123",
  "raw_bytes": 7072,
  "at":        "2026-08-03T14:00:00.694Z" }

Public internet → Cloudflare MX → Email Routing rule → Worker email() handler → D1 write. Nothing about that path required a paid plan.

Outbound: this corrects an earlier receipt

cloudflare-plan-costs.md recorded, from the pricing table’s “Outbound emails (Email Sending): Workers Free: Not available”, that a free-plan Node cannot send. That is too blunt. Measured:

Destination	Result
mystraits.ai@gmail.com, a verified Email Routing destination	sent successfully
someone@example.com, arbitrary	refused

The send_email binding also deployed without complaint and was reported as env.OUTBOUND (unrestricted).

So “not available” in the pricing table means arbitrary recipients are unavailable, not that the send path is dead. A free-plan Node can send to addresses already verified in the account, which is consistent with the pricing note that “sends to verified destination addresses are always free … on any plan”, but a reader of the plan comparison alone would conclude sending is impossible. It is not.

The refusal does not name the plan

Verbatim, on an arbitrary recipient:

destination address is not a verified address

Accurate, and unhelpful. It does not mention the plan, a paid upgrade, or domain verification. The probe checked explicitly and namesThePlan was false.

This is precisely the failure mode §5C exists to prevent and AGENTS.md calls a landmine: a refusal that names neither the cause the user can act on nor the way to fix it. Mailda must not surface this string. §11B requires doctor to distinguish outbound_verified_destinations_only from outbound_send_enabled; the send path must translate this error into that state and say which of verify the domain or upgrade the plan applies.

Superseded as a recommendation, 3 August 2026

ADR 25 makes Workers Paid mandatory; there is no free tier. The measurements below stand. They are facts about the platform and remain useful for understanding what the free plan does. The conclusion that this makes a good evaluation tier is withdrawn.

The reason is not cost. Cloudflare’s free plan forces 24-hour, non-configurable queue retention, while §22 requires retention to be set explicitly precisely because the default silently deletes unread messages. A free-plan Node is therefore not a limited Node but one that can lose mail, which disqualifies it for an evaluation meant to build trust. And the adoption argument was weak: the commitment a prospect actually makes is pointing MX at Cloudflare, not paying $5.

What this was going to mean for #19

The free plan is a working receive-only Node, not a crippled one:

• receives real mail from the public internet, unlimited and free
• stores, parses and indexes it
• can reply to verified addresses, so an evaluator can test a round trip to their own inbox without paying
• cannot reply to a customer

That is a stronger evaluation story than “receive-only” suggested. An evaluator points one address at a free Node, receives their own real mail, and can even exercise a reply to themselves before deciding to pay.

Residual

• Subdomain onboarding (mailda-test.straits-ai.com) was not tested. Cloudflare documents it as a dashboard-only flow, “select the apex domain, open Settings, under Subdomains enter the subdomain”, with no API or wrangler path, so it could not be automated. §10’s domain topology recommends a delegated subdomain as the default install, so this gap matters and should be closed.
• Free-plan queue behaviour (10,000 operations/day, 24-hour non-configurable retention) was not exercised; the probe used no queue.
• Whether the verified-destination allowance is per-account or per-zone was not tested.