Email API & SMTP Relay
Transactional and bulk email through a REST API or SMTP relay - with authentication, dedicated IPs, deliverability tooling and analytics that show you where every message went.
2
Ways in: REST API and SMTP
< 5 s
Median transactional delivery
99.99%
API availability
What is Email API & SMTP Relay?
Dollu Email API delivers the messages your product cannot afford to lose - password resets, receipts, one-time codes, shipping updates, invoices - and the campaigns your marketing team sends by the million, from a single platform. Send with POST /v2/emails and a JSON payload (or a template ID and variables), or point your existing application, CRM or on-premise system at smtp.dollu.com and change nothing else. Both paths land on the same queues, the same sending infrastructure and the same event stream.
Deliverability is the whole product. We handle DKIM signing, SPF and DMARC alignment and BIMI records for your sending domains with a guided set-up that verifies DNS in the console; give you a choice of shared IP pools segmented by sender reputation or dedicated IPs with automated warm-up; enforce list hygiene with suppression lists, bounce classification and complaint feedback loops from the major mailbox providers; and surface an inbox-placement and reputation dashboard so you find out about a blocklisting from us, not from your customers.
For developers there are templates with a Handlebars-style syntax and versioning, attachments and inline images, scheduled sending, batch requests of up to 5,000 recipients with per-recipient substitutions, idempotency keys and event webhooks for processed, delivered, deferred, opened, clicked, bounced, complained and unsubscribed. An address-validation endpoint checks syntax, domain, MX records and mailbox existence before you send, cutting bounces from imported lists and sign-up forms and protecting your sender reputation.
Sending infrastructure runs in Dollu's own facilities in Europe, the US, India and Singapore with region-pinned processing for data-residency requirements, TLS enforced on inbound and opportunistic or mandatory on outbound, message content retained only as long as you configure and access controlled by scoped API keys and SSO. Sub-accounts isolate brands or customers with their own domains, IPs and analytics, and a deliverability specialist is assigned to accounts sending more than one million messages a month.
CPaaS request and event flow: REST in, webhooks out.
Why choose Dollu for email api.
The advantages of buying from a carrier that owns its network, interconnects and operations - rather than a reseller.
Reach the inbox, not the spam folder
Authenticated domains, reputation-segmented IP pools, automated warm-up and feedback-loop processing are standard, and a reputation dashboard warns you before placement drops.
Migrate in an hour
Point your SMTP settings at smtp.dollu.com or swap a base URL in your SDK; templates, suppression lists and domains can be imported so nothing is lost in the move.
One event stream, every insight
Every message emits the same lifecycle events whether it came via API or SMTP, so analytics, alerts and your own data warehouse see one consistent picture.
Transactional and marketing, separated
Separate sub-accounts, IPs and domains for transactional and bulk mail keep a newsletter complaint from delaying a password reset.
Data where you need it
Choose EU, US, India or Singapore processing per sub-account, set content retention from zero to 30 days and meet GDPR and local residency requirements without a separate provider.
Capabilities in detail.
Everything included with Email API & SMTP Relay - the platform features, options and controls you get from day one.
- 01
REST API and SDKs
POST /v2/emails with JSON for recipients, content, template ID, variables, attachments, headers, tags and send_at; idempotency keys; SDKs for Node.js, Python, Java, Go, PHP and .NET; OpenAPI 3.1 specification.
- 02
SMTP relay
smtp.dollu.com on ports 25, 587 (STARTTLS) and 465 (implicit TLS) with API-key authentication; custom X-Dollu headers for tags, metadata and template selection so legacy systems get modern tracking.
- 03
Domain authentication
Guided DKIM (2048-bit) key generation, SPF include, DMARC policy recommendations and BIMI record support, with DNS verification in the console and alerts if a record disappears.
- 04
IP management and warm-up
Shared pools segmented by sender reputation, dedicated IPs from 100,000 messages a month with automated warm-up schedules, IP pool routing per sub-account or tag, and reverse-DNS managed for you.
- 05
Templates and personalisation
Handlebars-style templates with conditionals and loops, versioning and test sends, per-recipient substitutions in batches of up to 5,000, dynamic attachments and a visual editor for non-developers.
- 06
Event webhooks and analytics
processed, delivered, deferred, bounced, opened, clicked, complained and unsubscribed events as signed JSON; dashboards by domain, IP, tag and template; 90-day searchable logs and CSV/API export.
- 07
Address validation
POST /v2/email/validate checks syntax, domain, MX, disposable and role addresses and mailbox existence in real time; bulk validation of lists up to one million rows with a downloadable report.
- 08
Suppression and compliance
Automatic suppression of hard bounces, complaints and unsubscribes; RFC 8058 one-click List-Unsubscribe headers; group-level preferences; GDPR erasure endpoint; audit logs.
- 09
Inbound parsing
Point an MX record at Dollu and receive inbound email as parsed JSON (headers, text, HTML, attachments) on your webhook - for reply handling, ticketing and support automation.
How it works.
From first conversation to live traffic - a tracked, engineer-led onboarding with a named owner at every step.
- Step 01
Verify your domain
Add your sending domain in the console, publish the DKIM, SPF and DMARC records we generate and confirm with one click. Verification usually completes within minutes.
- Step 02
Choose API or SMTP
Create a scoped API key. Either call POST /v2/emails from an SDK or set smtp.dollu.com with the key as your SMTP password in the application you already have.
- Step 03
Send and watch events
Send a test, subscribe your webhook to delivered, bounced and complained events and check the message timeline in the console. Add templates and tags as you go.
- Step 04
Warm up and scale
Move to a dedicated IP with automated warm-up as volume grows, split transactional and marketing into sub-accounts and work with a deliverability specialist above one million messages a month.
Who uses this and why.
Typical deployments across carriers, enterprises, platforms and contact centres.
Transactional email for SaaS and apps
Password resets, magic links, invitations and receipts sent in seconds with delivery events wired back into your product analytics.
E-commerce receipts and shipping
Order confirmations, shipping notices and abandoned-basket reminders with per-recipient personalisation and click tracking that respects consent.
Financial statements and alerts
Statements, transaction alerts and regulatory notices from region-pinned infrastructure with mandatory TLS, short retention and full audit trails.
Newsletters and campaigns
High-volume marketing sends on dedicated IPs with warm-up, list-unsubscribe compliance, suppression management and campaign-level analytics.
Legacy systems over SMTP
ERP, ticketing and on-premise applications relay through smtp.dollu.com and gain authentication, tracking and reputation management without code changes.
Technical & commercial specifications.
Key parameters at a glance. Ask us for the full service description and SLA document.
| API | REST/JSON at api.dollu.com/v2/emails; OpenAPI 3.1; SDKs for six languages |
|---|---|
| SMTP | smtp.dollu.com; ports 25, 587 (STARTTLS), 465 (TLS); AUTH with API key |
| Authentication | DKIM 2048-bit, SPF, DMARC, BIMI; guided DNS set-up and monitoring |
| IPs | Shared reputation pools; dedicated IPs from 100k msgs/month; automated warm-up |
| Throughput | Batches of 5,000 recipients per request; 1M+ messages per hour on request |
| Webhooks | processed, delivered, deferred, bounced, opened, clicked, complained, unsubscribed |
| Validation | Syntax, MX, disposable, role and mailbox checks; bulk lists up to 1M rows |
| Data residency | EU (Frankfurt, Amsterdam), US (Ashburn), India (Mumbai), Singapore |
| Retention | Content 0–30 days configurable; event logs 90 days; GDPR erasure endpoint |
| Billing | Per 1,000 messages with volume tiers; dedicated IPs monthly; validation per lookup |
How APIs / CPaaS are priced.
APIs are usage-based: per minute, per message, per verification, per participant-minute or per email - at carrier pricing, because Dollu’s own network sits underneath the endpoints.
We publish the model, not a public rate card - actual rates depend on destination, route class, volume and regulatory cost. See how every Dollu service is priced.
- Free sandbox for development and testing
- Sub-account and reseller rate decks
- Committed-spend discounts by monthly usage
- No platform fee at entry volumes
- Numbers added at rental + usage
- Billing
- Metered per unit; prepaid balance or postpaid invoicing; usage visible in real time in the portal and API
- Commitment
- None; committed monthly spend earns tiered discounts
Email API - your questions answered.
The questions customers and carriers ask us most often before they interconnect. If yours is not here, our team answers within one business day.
Still have a question?
Ask our solutions teamRelated services.
Services customers commonly combine with Email API & SMTP Relay.
Move your email in an afternoon.
Verify a domain, send a test through the API or SMTP and see events flow - or ask [email protected] for a deliverability review of your current setup.
