Documo fax alternative
Documo, formerly mFax, includes fax sending and receiving, document processing, and a web dashboard. mintfax provides outbound fax through an API. Your choice will depend partly on whether you need those additional tools or an API for sending documents from your own application.
Feature comparison
| Feature | Documo (mFax) | mintfax |
|---|---|---|
| API style | REST/JSON | REST/JSON |
| API access | Business plan ($150/mo) plus a separately purchased API Add-On | Every tier, with no add-on or minimum plan |
| Production auth | HTTP Basic (Authorization: Basic YOUR_API_KEY) | Bearer token (Authorization: Bearer mfx_live_...) |
| Environment scoping | Sandbox at api.sandbox.documo.com; production key otherwise | Environment inferred from key prefix (mfx_test_, mfx_live_, mfx_acct_) |
| Per-page price | Bundled per plan: 300 / 800 / 2,500 / 6,000 pages per month | $0.060/page standard; $0.048 at 100k+/mo; $0.036 at 1M+/mo |
| BAA | Included on every paid plan; signed by Sales on request | Free BAA in the dashboard; separate DPA |
| Webhook signing | None; HTTP Basic on the receiver plus optional single trusted-IP allowlist | HMAC-SHA256 per Standard Webhooks; per-endpoint whsec_ secret; three headers |
| Idempotency on send | Not documented | Idempotency-Key header; 24h expiry; 409 on reuse; hint header on omit |
| Send retries | No per-fax retry parameter documented; failed faxes re-sent via POST Resend endpoint with the previously-failed messageID | Per-fax max_attempts 1-5; backoff 1m / 3m / 5m / 5m; default 3 attempts |
| Webhook retries | 7 attempts at 5s / 25s / 2m / 10m / 52m / 4h / 22h | 3 attempts (10s / 60s / 300s), then stop |
| Error model | Numeric Fax Result Codes 1000-9000; machine-readable API error strings not published | 17 API error codes plus 10 delivery error codes plus error_subcode |
| Request tracing | Not documented | X-Request-Id: req_<ULID> on every response; echoed as request_id |
| Sandbox | Provisioned by emailing [email protected]; virtual email inbox; one inbound simulator | Nine test numbers, nine scenarios; same API as live; available through the API |
| Dashboard | Template gallery, click-to-insert cover-page editor, User/Admin roles, Reports with “Descendants” roll-up | Keys, recent faxes, webhook attempts, balance, retention mode |
| Cover pages | Custom-template editor with click-to-insert tokens and per-user templates | Built-in templates; per-env and per-fax configurable; token substitution |
| Inbound / receive | Yes (fax.v1.inbound.init / .page / .succeed / .failed / .complete events; portal DID provisioning) | No (outbound only) |
| Account model | Account plus subaccounts/departments; per-subaccount users, account- or number-scoped webhooks, per-subaccount history with a Reports “Descendants” roll-up | One account; one sandbox and one live workspace; no subaccounts |
| Bundled products | Cloud Fax, IDP, eSignatures, Integrations under one brand | Fax-only |
| Certifications | HIPAA (via BAA), SOC 2, PIPEDA (per mFax landing) | HIPAA (via BAA); DPA for GDPR / UK GDPR / LGPD; no SOC 2, HITRUST, PCI, ISO, FedRAMP |
API access and pricing
Documo requires a Business plan or higher and a separate API add-on. mintfax includes API access at every price tier, with prepaid per-page pricing. See pricing for mintfax’s rates.
Documo bundles pages, users, and fax numbers into monthly plans. mintfax has no monthly minimum or charge per user.
Delivery updates and duplicate requests
Documo recommends HTTP Basic authentication for webhook receivers. Its public webhook guide does not describe payload signatures. mintfax signs every webhook using HMAC-SHA256 under the Standard Webhooks specification.
Documo’s public fax documentation does not describe an idempotency key. mintfax accepts an Idempotency-Key on send requests. Repeating the same request with the same key within 24 hours returns the stored response without submitting another fax.
Testing
Documo creates sandbox accounts through support. Its sandbox includes a virtual email inbox and an inbound fax simulator.
You can register for mintfax’s sandbox through the API. Nine test numbers simulate successful delivery and failures such as busy lines, invalid numbers, and insufficient credit. No credit card is required.
Agreements and stored content
Documo includes a BAA with its paid plans and directs signing enquiries to sales. mintfax provides a BAA and a separate DPA in the dashboard, with signed PDFs available immediately.
mintfax keeps fax content for 30 days by default, configurable between 7 and 365 days. Zero-footprint mode deletes patient information after delivery or failure. See compliance for details.
Other requirements
Documo provides tools that mintfax does not: inbound fax, a cover-page editor, user roles, reporting, and subaccounts for resellers. It also offers eSignatures and document processing.
If you need those features, include them in your comparison. For an outbound integration, the Documo migration guide explains the API changes needed to use mintfax.