Question 1

How does Inbox OSS pricing compare to SendGrid?

Accepted Answer

SendGrid uses a multi-tier per-feature pricing model where transactional API, marketing campaigns, automations, and dedicated IP are sold as separate add-ons or upgrade tiers. Inbox OSS uses transparent volume-based pricing where **every plan includes every feature**. A 50,000 message per month workload on SendGrid Essentials plus Marketing Campaigns Pro typically costs $89-$129 per month; the equivalent on Inbox OSS Starter is $19 per month. For dedicated IP customers, SendGrid Pro starts at $89 per month before the dedicated IP add-on; Inbox OSS Pro includes the warmed dedicated IP in the $89 base.

Question 2

How does Inbox OSS pricing compare to Mailgun?

Accepted Answer

Mailgun uses per-message tiers (Foundation $35/mo for 50k, Growth $80/mo for 100k, Scale $90/mo for 100k with HIPAA). Marketing automation is restricted to higher tiers. Inbox OSS Starter covers 50,000 messages with the full marketing + automation suite for $19/mo; Pro covers 500,000 messages with a dedicated IP for $89/mo. Validation credits are included in every Inbox OSS tier; Mailgun charges separately for validation through their Mailgun Validations product.

Question 3

How does Inbox OSS pricing compare to Postmark?

Accepted Answer

Postmark sells per-message at roughly $1.25 per 1,000 messages on volume tiers. For 50,000 messages a month, that is approximately $50-$62 per month for transactional only — Postmark does not include marketing campaigns or automations in any plan. Inbox OSS Starter covers 50,000 messages including marketing campaigns, drips, automations, and validation for $19 per month. For pure transactional workloads where you do not need the marketing suite, Postmark and Inbox OSS Free (3,000 messages) or Starter are comparable; for any team that also needs marketing email, Inbox OSS is structurally lower cost.

Question 4

Do you charge for bounced or undelivered emails?

Accepted Answer

No. You pay only for emails we accept (HTTP 202) at the API or SMTP boundary. Hard bounces, soft bounces, suppressions, rejected addresses, and dropped sends are not metered. Pre-send validation (catching the bad address before you spend a send credit) is metered separately at our validation tier rates, which are roughly an order of magnitude cheaper than the cost of a bounce in lost reputation. For high-volume senders this is the largest single cost-optimization lever — every customer using validation sees overall blended cost-per-delivered-message decrease.

Question 5

Can I bring my own dedicated IPs?

Accepted Answer

Yes on Pro and Enterprise plans. We will inherit your existing IP reputation if you bring a warmed IP, or run a fresh warmup schedule if you bring cold IPs. Each dedicated IP has its own reputation tier surfaced in your dashboard, and you can configure separate IP pools for transactional, marketing, and notification traffic. For Enterprise customers, we offer up to 50 dedicated IPs in a single account with automatic load balancing weighted by IP reputation.

Question 6

Is there a free trial of paid plans?

Accepted Answer

Every paid plan (Starter, Pro) includes a 14-day trial with no credit card required. You can send up to the Starter tier limits (50,000 messages, 3 domains, 5,000 validations) during the trial. The Free plan stays free forever — you do not need to upgrade to keep using the platform if 3,000 messages per month is enough. Enterprise evaluations are bespoke; contact sales to set up a sandbox tenant with your domains pre-authenticated.

Question 7

How does overage billing work?

Accepted Answer

You have two options. **Hard cap** (default): we stop accepting messages when you hit your monthly limit; you get email and webhook alerts at 80%, 95%, and 100%. **Pay-as-you-go overage**: messages over your monthly limit bill at the same per-message rate as your plan tier. No surprise bills, no 2× or 5× penalty rates that other platforms use. You can switch between hard cap and pay-as-you-go at any time from Settings → Billing.

Question 8

Do you offer annual billing discounts?

Accepted Answer

Yes. Annual billing receives a 17% discount on all paid plans (Starter, Pro). Enterprise contracts can be 1-year, 2-year, or 3-year with progressively deeper discounts and multi-year price locks. Annual billing also unlocks SOC 2 report direct delivery (you do not need to NDA each time you renew) and customer-success benefits like a free deliverability audit on contract sign.

Question 9

Do you offer non-profit or open-source discounts?

Accepted Answer

Yes. Registered 501(c)(3) non-profits and equivalent organizations in other countries receive 50% off Starter and Pro plans. Open-source projects with a public source repository and active maintainer community receive a free upgrade to Starter for the project email account. Apply for either program by emailing community@inbox.onesourcesoft.com with proof of status — we respond within 2 business days.

Question 10

Can I self-host instead of using your cloud?

Accepted Answer

Yes. Inbox OSS is open-source at its core. The same code that powers our managed cloud is available for self-hosting on Docker Compose, Kubernetes, or directly on Linux servers. Self-hosting is free for the core software (you pay only for your own infrastructure). We offer paid support tiers for self-hosted production environments — Starter ($499/mo), Business ($2,499/mo), and Enterprise (custom) — covering deployment review, deliverability tuning, on-call escalation, and direct access to our platform team.

Question 11

What happens to my data if I cancel?

Accepted Answer

You retain full access through the end of your paid period. After cancellation, your data is retained for 90 days in case you want to reactivate, then permanently deleted. You can export everything at any time: messages, events, suppressions, contacts, templates, and audit logs — all exportable as CSV or JSON from the dashboard, or via API. We do not hold your data hostage and we will not increase prices to force you to stay.

Feature	Free	Starter	Pro	Enterprise
Sending
Transactional Email API (SendGrid v3 compatible)
SMTP relay (TLS 1.3, STARTTLS)
Marketing campaigns + drag-drop builder
Marketing automations + visual flow editor
Inbound Parse (receive email as JSON)
Mailgun-compatible /messages endpoint
Deliverability
Shared IP pool (segmented by reputation)
Dedicated IP (warmed)			1 included	Up to 50
Adaptive IP warmup automation
FBL ingestion + blocklist monitoring
Gmail / Yahoo / Microsoft postmaster integration
Seed-list inbox-placement testing
Email Validation
Free validations per month	100	5,000	50,000	Custom
Bulk CSV/TXT validation processor
WHOIS domain-age check (7-check engine)
Pre-send validation hook
Team & access
Team members	1	5	25	Unlimited
API keys with IP allowlist
SSO (SAML 2.0 / OIDC)
SCIM 2.0 provisioning
Admin audit log export
Compliance
SOC 2 Type II
GDPR DPA + EU region data residency
HIPAA BAA
Custom MSA / DPA addenda
Support
Community Slack support
Email support (same-business-day)
Priority support (4-hour SLA)
Dedicated Customer Success Manager
24×7 emergency on-call

Pay for what you send. Not for fancy dashboards.

Pricing built for predictability

What counts as a sent email?

How dedicated IP pricing works

How validation credits work

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