Buttondown

buttondown.com/pricingNewsletter sender with a REST APIemail/buttondownJSON compare report an error provider JSON

Free allowance: Free for the first 100 subscribers, with the price assuming at most one email a day to the whole subscriber base; API included, no card
Verdict: caveatusable, with a named limit or an unprobed read path
Cost: free tier
Identity: emailno card, no phone
Binding limit: request-ratethe free price assumes at most one email a day to the whole subscriber base; more needs a contact with the vendor; 600 API requests per minute on every endpoint, and 100 subscriber creations per day through POST /v1/subscribers; new...
Evidence: documented48 sources; a first-party page was read and the sentence quoted
Freshness: stale on 2026-12-03checked 2026-11-02 (live); stale on 2026-12-03

Free tier	free for the first 100 subscribers, with the price assuming at most one email a day to the whole subscriber base; API included, no card unit users; metered on identity-count; The quota counts subscribers, not messages. Sending from a custom domain is free; without one, mail goes out from the account's username at buttondown.email. Attachments, tagging and segmentation, automations and archives on a custom domain are paid add-ons. Subscribers are confirmed by double opt-in unless created through the API with type regular.
Price	none stated
Limits	request-rate (binding) the free price assumes at most one email a day to the whole subscriber base; more needs a contact with the vendor source request-rate (binding) 600 API requests per minute on every endpoint, and 100 subscriber creations per day through POST /v1/subscribers source write-gated every new account is reviewed before it can send, most reviews within one to three business days source request-rate (binding) new senders are capped per hour until they reach a baseline of engagement and reputation; the figure is not stated source counts of things, not rates, so no vocabulary kind names them: 100 subscribers on the free plan.
Binding	request-rate one email a day to at most 100 subscribers: the subscriber ceiling caps the recipients and the daily assumption caps the sends.
Identity	email The register page asks for a username, an email address and a password, or Apple or Google sign-in, and states that no card is needed. Every new account is reviewed before it can send, and a verification form asks what the newsletter is about, who its audience is, where imported subscribers came from, and details of the person or organization. No domain is needed: mail goes out from the username at buttondown.email by default. A custom sending domain is free, set up either by delegating a subdomain with two NS records (managed) or by adding the records shown in settings (manual).
Egress	not applicable: an outbound sender
Per-object cap	not applicable: email attachments are a paid add-on
Retention	not stated
Interface	rest the REST API at https://api.buttondown.com/v1 with an OpenAPI spec: POST /v1/emails creates an email for the subscriber base; POST /v1/subscribers/{id_or_email}/emails/{email_id} takes no request body and sends an existing finalized email to one subscriber, and a draft is refused with a 400 whose code is email_invalid_status; POST /v1/emails/{id}/send-draft delivers a draft to the subscriber ids and email addresses named in its body, the documented route for sending drafts for review
Tooling	curl or any HTTP client; there is no official SDK, and typed clients are generated from the OpenAPI spec
Composes with	a list sender rather than a transactional relay: every recipient is a subscriber, so it carries a newsletter or a notification list of up to 100 people, and per-message transactional mail belongs on a relay.
Reliability	sending is disabled temporarily when unsubscribes, complaints or hard bounces run high on a new sender
Notes	The vendor's summary file (llms.txt) lists API access and custom domains under a USD 9 Basic plan, while the API page, the plan badge on the API guides and the January 2025 pricing post place API access on the free plan, and the sending-domain page and the pricing page place custom-domain sending there; the summary file is out of date.
Evidence note	documented no message was sent and no authenticated request was made; the free plan, the API on the free plan, the finalized-only rule of the per-subscriber send endpoint and the rate limits are documented, while the response a free account's key gets from that endpoint, whether an email can reach a final status without a send to the list, and the account review with its verification form are unverified: behind a sign-up.
Parsed numbers	has-free-tier 1

Evidence 48

date	source	what it proved
2026-10-30	buttondown.com/pricing	the free plan covers the first 100 subscribers
2026-10-30	buttondown.com/pricing	the free price assumes at most one email a day to the whole list
2026-10-30	buttondown.com/pricing	tagging and segmentation is listed among the add-ons at 9 per month
2026-10-30	buttondown.com/pricing	email attachments are listed among the add-ons at 9 per month
2026-10-30	buttondown.com/llms.txt	the free tier is up to 100 subscribers with no stated email count
2026-10-30	buttondown.com/llms.txt	the summary file lists API access and custom domains under the 9 per month Basic plan
2026-10-30	buttondown.com/features/api	the API is on the free plan
2026-10-30	docs.buttondown.com/api-rate-limits	every API endpoint allows 600 requests per minute
2026-10-30	docs.buttondown.com/api-rate-limits	subscriber creation through the API is limited to 100 a day
2026-10-30	buttondown.com/register	registration needs no card
2026-10-30	buttondown.com/register	the register form asks for a username, an email address and a password, beside Apple and Google sign-in
2026-10-30	docs.buttondown.com/account-review	part of the text of Limits, above
2026-10-30	docs.buttondown.com/account-review	most reviews finish within one to three business days
2026-10-30	docs.buttondown.com/account-review	the verification form asks about the newsletter, its audience, imported subscribers and the person or organization
2026-10-30	buttondown.com/blog/sending-email-address	without a custom domain, mail goes out from the username at buttondown.email
2026-10-30	docs.buttondown.com/sending-from-a-custom-domain	a custom sending domain is free
2026-10-30	docs.buttondown.com/sending-from-a-custom-domain	the managed domain setup delegates a subdomain with two NS records
2026-10-30	docs.buttondown.com/sending-from-a-custom-domain	part of the text of Limits, above
2026-10-30	docs.buttondown.com/sending-from-a-custom-domain	sending is disabled temporarily on high unsubscribes, complaints or hard bounces
2026-10-30	docs.buttondown.com/double-opt-in	subscribers are confirmed by double opt-in by default
2026-10-30	docs.buttondown.com/api-subscribers-create	a subscriber created through the API with type regular skips the confirmation
2026-10-31	docs.buttondown.com/openapi.json	the API sends a specific email to a specific subscriber
2026-10-30	buttondown.com/blog/safer-email-api-defaults	the first API send of a key needs a one-time confirmation header
2026-11-02	buttondown.com/blog/2025-pricing-update	the January 2025 pricing post states that API access became available to everyone, down from USD 9 a month
2026-11-02	buttondown.com/blog/api-send-draft-status	a draft sent through the per-subscriber endpoint is refused with the error code email_invalid_status
2026-11-02	docs.buttondown.com/api-subscribers-send-email	the endpoint guide limits the per-subscriber endpoint to finalized emails and names the send-draft endpoint for drafts
2026-11-02	buttondown.com/pricing	the pricing page still prices the first 100 subscribers at nothing
2026-11-02	buttondown.com/features/api	the API page answers that the API is available on all plans, including free
2026-11-02	docs.buttondown.com/drafting-emails-via-the-api	the API guide for drafting emails carries the plan badge Available on the Free plan
2026-11-02	buttondown.com/buttondown/archive/updates-from-january-9711/	the vendor's update dated February 10, 2025 states that everyone on the free plan has API access
2026-11-02	buttondown.com/pricing	the prices assume at most one email a day to the whole subscriber base, and a higher volume needs a contact with the vendor
2026-11-02	buttondown.com/pricing	sending from a custom domain is listed in what the free price includes
2026-11-02	buttondown.com/register	registration needs no card
2026-11-02	buttondown.com/register	the register form asks for a username, an email address and a password, beside Apple and Google sign-in
2026-11-02	docs.buttondown.com/openapi.json	the OpenAPI spec names https://api.buttondown.com/v1 as the API server
2026-11-02	docs.buttondown.com/openapi.json	the spec describes POST /emails as creating a new email
2026-11-02	docs.buttondown.com/openapi.json	the spec describes POST /subscribers/{id_or_email}/emails/{email_id} as sending a specific email to a specific subscriber
2026-11-02	docs.buttondown.com/openapi.json	the spec describes POST /emails/{id}/send-draft as sending a draft email to specific recipients
2026-11-02	docs.buttondown.com/openapi.json	the send-draft body takes a list of subscriber ids
2026-11-02	docs.buttondown.com/openapi.json	the send-draft body takes a list of email addresses
2026-11-02	docs.buttondown.com/api-subscribers-send-email	the sample request for the per-subscriber endpoint sends no request body
2026-11-02	buttondown.com/blog/api-send-draft-status	the per-subscriber endpoint no longer sends non-final emails such as drafts
2026-11-02	buttondown.com/blog/api-send-draft-status	a draft sent through the per-subscriber endpoint gets a 400 response
2026-11-02	docs.buttondown.com/api-rate-limits	every API endpoint allows 600 requests per minute
2026-11-02	docs.buttondown.com/api-rate-limits	subscriber creation through the API is limited to 100 requests a day
2026-11-02	docs.buttondown.com/account-review	part of the text of Limits, above
2026-11-02	docs.buttondown.com/account-review	most reviews finish within one to three business days
2026-11-02	docs.buttondown.com/account-review	an account under review cannot send emails, though it can draft them

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stale after days	90