Pricing

Pricing is per page, not per fax, and prepaid. Three per-page rates apply automatically as monthly volume rises, with no negotiation and no enterprise tier above them. Every mintfax feature is on every tier, including a free, self-serve BAA. Sandbox is free; live access activates on your first credit purchase.

Plans

All prices in USD. Volume tiers apply automatically at the stated monthly page counts. There is no negotiation and no sales call to reach the lower rates. There is no enterprise tier above these three, and there is no sales call to reach any feature or price.

What is included

Every mintfax feature is on every tier. There is no free-vs-paid feature ladder. Sandbox and live expose the same API contract. Three parity exceptions apply between them:

• Sandbox top-ups skip Stripe (simulated).
• Sandbox faxes go to a deterministic simulator instead of the PSTN.
• Live requires a first credit purchase to activate.

Feature availability is not one of them.

• OpenAPI-first contract. OpenAPI 3.1 spec, llms.txt at the service root, markdown docs, error responses with machine-readable action hints, and deterministic sandbox scenarios.
• Signed webhooks. HMAC-SHA256 signing per Standard Webhooks, per-endpoint whsec_ secret, three delivery headers (webhook-id, webhook-timestamp, webhook-signature), three retries at 10s, 60s, and 300s, per-attempt log, and manual retry of any past attempt.
• Idempotency keys. Idempotency-Key header on POST /faxes, 24-hour expiry, 409 idempotency_key_reuse when the same key is reused with a different body, 409 idempotency_key_in_progress on in-flight collisions, and Idempotent-Replayed: true on the replay.
• Error catalog. 17 public API error codes and a 10-code stable public carrier-error taxonomy, plus an optional error_subcode for finer detail. Carrier identity is never exposed.
• Sandbox. Nine magic numbers with deterministic outcomes (delivered, busy, no-answer, delayed-delivery, line-quality failure, insufficient balance, delivered multi-page, invalid number, validation failure). Same API contract as live.
• Compliance. Compliance controls are included at every tier. Free, self-serve BAA in the dashboard with a durable evidence record. DPA via the same path. AES-256 at rest, TLS 1.2+ in transit, configurable retention (7 to 365 days, default 30), active per-fax content deletion via DELETE /faxes/{id}/content, optional automatic deletion of PHI after a fax reaches a terminal state, hash-chained audit stream retained 6 years, and audit export via GET /v1/account/audit and dashboard CSV.

The free, self-serve BAA is on every tier. No sales call. No enterprise upsell.

How mintfax bills

mintfax bills a prepaid credit balance. A credit hold is placed on submission, captured on delivery, and released on permanent failure. Carrier errors never bill; the hold is released.

Auto top-up is opt-in per credit pool. When enabled, mintfax re-purchases the chosen credit package once the pool falls below the 20% depletion threshold. The same 20% threshold fires a balance.low webhook, so your systems can react before the top-up settles.

Credits pool at the account level. Each account has one sandbox pool and one live pool, each shared across every environment of that type. Sandbox is free and always active. Live access is gated on the first successful live credit purchase.

No setup fees. No long-term contracts. No monthly minimum. No seat licensing. No feature gating. Payments run through Stripe on Visa, Mastercard, American Express, and Discover.

How mintfax compares

Most evaluator shortlists include four fax APIs. Sinch (Phaxio) is a long-running developer brand with clean docs. Telnyx has the cheapest published per-page rate and 90+ country coverage. Documo carries HITRUST plus SOC 2 Type II and offers in-document processing. eFax has the largest US install base under Consensus, along with HL7/FHIR and HITRUST. The table below sets each against mintfax on price, BAA terms, and one further strength and one weakness. Prices verified against vendor pages on 2026-07-16. Per-vendor depth is at /compare and the per-vendor pages linked below.

Start in the sandbox

The sandbox is free. No card, no BAA needed to start. The quickstart sends a first fax from request to delivery.

Open the sandbox