Email API FAQ

Install the SDK and send to a sandbox address like delivered@messagebird.dev in about five minutes, before you even verify a domain.

Transactional and marketing sending, templates, sending domains with DKIM/SPF/DMARC, dedicated IPs and pools, suppression, inbound, webhooks, and deliverability analytics, all on one API.

Start free with 1,000 emails a month, no card. Paid plans begin at $15 for 50K, and the per-message rate drops as you scale.

Yes. Both go through the same send API; the only difference is the category field, which decides how suppression and unsubscribes are applied. Pick transactional for password resets and receipts, marketing for campaigns.

Up to 100 independent messages per batch call, each with its own recipient, subject, and variables. The batch is validated as a unit, so one invalid message rejects the whole call with a 422: you never half-send. A single message takes 1–50 recipients across to, cc, and bcc.

Send an Idempotency-Key with each logical send. If the original request succeeded but the response was lost, replaying with the same key returns the original result (marked with an Idempotency-Replay header) instead of sending again.

Single sends and batches have separate limits: on the free tier, 10 single sends and 5 batch calls per minute (5 × 100 = 500 messages/min), rising to 1,000 sends and 100 batch calls per minute on Growth. Limits count requests, not recipients, so batching is the volume lever.

Send to a sandbox address such as delivered@messagebird.dev, the outcome is decided by the address, not your account state, so you can exercise sends, webhooks, and suppression before you verify a domain. Addresses like bounce@ and complaint@ simulate those outcomes through the real pipeline.

No. You can create and manage templates entirely through the API: send your HTML with a list of declared variables, and reference the template by id when you send. The builder is one way in, not the only one.

A stored template is referenced by id and versioned, and its personalization renders on Bird's side at send. So you send only the per-recipient values, not the whole body each time, and the layout and logic live in one place instead of being rebuilt in your code on every call.

Conditionals, loops over arrays, nested fields, and per-field defaults, all resolved per recipient at send. A membership block can show only for members; an order can list its line items. The logic is stored in the template, so a flat key-value payload per recipient is enough to drive it.

Yes. Render your React Email components to HTML and store the result as the template body. For per-recipient values, leave Bird's tokens as literal text in the JSX so they survive the render and get filled at send, rather than baking in a value when React renders.

Publishing freezes an immutable, numbered version. Editing happens on a draft and never touches what's live until you publish, and you can roll back to any earlier published version and re-publish it. Each version keeps a stable identity, which is what lets per-template reporting attribute sends correctly.

They're what we're building toward, not what ships first. The API (HTML with declared variables) and React Email are the authoring paths available today; a visual builder, prompt-to-template generation, and an agent compose surface come on top of the same stored-template model.

The send call is unchanged: reference the template by id and pass the per-recipient values, and the existing email send API handles the rest. There's no separate template-send endpoint to learn.

Global. A contact is unique by email, and audiences just reference it. Move a contact between audiences and its attributes follow, because they live on the contact, not the list.

A closed, typed schema for your custom contact fields. You declare each field's type (string, number, or boolean) with an optional fallback up front; unknown keys or wrong-typed values are rejected when you write them, so your data stays clean.

Batch-upsert up to 1,000 contacts in one call, and join them to an audience in the same request, with no separate add step. Upsert is idempotent on the identifiers each entry carries, so re-running an import updates rather than duplicates.

A broadcast targets a single audience. Build and maintain the audience here; reference it by ID when you send.

Point it at a single audience. Audience is the one targeting concept; you don't stack lists and segments. Dynamic and warehouse-backed audiences are on the roadmap as audience types, not separate fields.

Yes. Send immediately, or schedule with an explicit timestamp from 30 seconds to 30 days in the future.

Yes. Cancel a scheduled broadcast, or one that's already fanning out. A broadcast can move to canceled from any non-terminal state.

Add the domain, paste the generated DNS records at your provider, and hit verify. Most verifications resolve within minutes of DNS propagation, though it can occasionally take longer.

Bird generates them for you: a DKIM TXT record to sign your mail, a return-path CNAME that aligns SPF (no apex SPF record required), and a DMARC TXT record. A tracking CNAME for branded open/click links is optional. Add them at your DNS provider and verify.

DMARC tells receiving servers what to do with mail that fails DKIM or SPF alignment, and where to send the aggregate reports that show who is sending as your domain. Bird requires a DMARC record before a domain can send, and recommends starting at p=none, which monitors without affecting delivery. Once you have confirmed every legitimate source aligns, tighten the policy to p=quarantine or p=reject. If you already publish DMARC at your domain or a parent domain, Bird uses it as is. Major inbox providers now expect bulk senders to publish a policy, so having one is increasingly part of reaching the inbox at volume.

Yes, and it's recommended. Sending from a dedicated subdomain isolates your email reputation from your corporate mail.

Yes. Run separate domains for transactional and marketing mail, or one per brand, each with its own authentication and reputation.

Once you're sending consistently high volume, roughly 100,000 emails a month or more. Below that, a shared pool gives better deliverability because reputation is pooled, and a dedicated IP only helps when you send enough to keep it warm.

No. Bird warms a new dedicated IP automatically over roughly 30 days, ramping volume so mailbox providers build trust gradually, with overflow on the shared pool so you never drop volume.

Yes. Group IPs into pools and route each traffic type to its own pool, so a marketing send can't affect the reputation that carries your password resets.

$24.95 per month per dedicated IP on the Growth plan, up to five. There's no setup fee and no annual commitment.

Deliverability is whether your email actually reaches the recipient's inbox rather than the spam folder or a hard rejection. It depends on authentication, sender reputation, list hygiene, and engagement, all of which Bird manages or surfaces for you.

Bounces, spam complaints, and unsubscribes automatically add the recipient to your suppression list, so you stop mailing addresses that damage your reputation. Suppression is reversible if an address recovers.

Bird monitors the major blocklists and exposes bounce codes, complaint types, and mailbox-provider breakdowns through the stats API and dashboard, so you can catch a downward trend early.

Hard bounces, spam complaints, and unsubscribes. Once a recipient triggers one of these, Bird adds them to your suppression list and skips them on future sends.

Yes, suppression is reversible. If an address recovers, remove it from the list through the dashboard or API and resume mailing it.

Yes. Add addresses manually, for instance a known-bad list you're importing, and they'll be skipped just like automatic entries.

Hard bounces and manual entries block every send. Complaints and unsubscribes scope to marketing only, so a transactional message like a password reset still reaches someone who opted out of your campaigns.

Send to the sandbox address suppressed@messagebird.dev. It short-circuits exactly as if the recipient were on your list (rejected with recipient_suppressed), without writing anything to the list, so it's reusable.

Delivery, opens, clicks, bounces, complaints, and unsubscribes, summarized as KPIs and broken down by domain, ISP, IP, sending domain, recipient domain, tag, and broadcast, with bounce-code and complaint-type detail.

Yes. Everything the dashboard charts is available through the stats API, at daily or hourly granularity, so you can backfill reports or stream metrics into your own tools.

Engagement and delivery events arrive in near real time via webhooks and roll up into the stats endpoints, so dashboards and queries reflect what just happened, not yesterday.

Yes. Mailbox-provider and client breakdowns show how Gmail, Yahoo, Outlook, Apple Mail, and others deliver, open, and bounce your messages.

A real, addressable inbox your code owns. Mail sent to it lands in threads your agent can read, filter, reply to, and send from over the API, without running an IMAP server or parsing raw MIME.

Inbound parsing hands you raw messages. A mailbox adds the conversation layer: a claimed address, threads with labels, quote-stripped text, and replies that fold back in.

Yes. A mailbox lives on the shared inbox.ai domain or on your own domain, inbound forwarding must be configured on that domain first. Any local part that is not in its 30-day post-deletion quarantine is available.

Scoped keys, audited writes, and category-aware suppressions: a marketing send cannot reach a suppressed recipient. Inbound floods are contained too, since blocked mail wakes no webhooks.

A generated handle is 20 random characters, always available and free. A custom handle is one you pick (goldcrest@inbox.ai), first-come first-served across all organizations, and it comes out of your plan's allowance.

Nothing breaks. Handles you already claimed keep working; you just can't claim new ones until you're back under the allowance.

They count toward your overall mailbox quota like any mailbox, and their local parts never touch the custom-handle allowance.

If you only need mail parsed into a webhook, plain inbound email is enough. A mailbox earns its keep when the agent has to hold a conversation.

Create an API key in the dashboard, claim an address, and reply to your first thread in a few minutes. The docs walk the whole loop, and the hosted MCP server gives an agent the same tools without any HTTP glue.

The same one. Marketing and transactional email share one API, one set of keys, and one analytics surface. Broadcasts add the campaign lifecycle on top of the sending infrastructure you already use. You still decide how to separate their sending reputations.

Every send is authenticated with DKIM, SPF, and DMARC, your IPs are warmed automatically, and bounces and complaints suppress automatically so a bad address never burns your reputation twice. Blocklist monitoring flags a problem while you can still act on it.

Yes. Unsubscribes and complaints suppress the recipient automatically and reversibly, and one-click List-Unsubscribe is built in. A broadcast applies your marketing suppressions before it sends.

Delivery, opens, clicks, bounces, and complaints broken down by campaign, tag, and mailbox provider, with prefetched opens filtered out. Everything in the dashboard is also available through the stats API.

Both are on-prem MTAs you run yourself instead of sending through Bird's managed API. Momentum MTA is built around customizable workflows and routing for high-volume sending; PowerMTA is built to run on your own servers or any public cloud, such as AWS or Azure.

No. Inbox Tracker and Competitive Tracker are deliverability-intelligence products: Inbox Tracker measures inbox placement and reputation from real mailbox data, and Competitive Tracker benchmarks your program against other brands. Neither requires self-hosting your sending infrastructure.

Teams with infrastructure or compliance requirements that call for running their own MTA, and teams that want independent visibility into inbox placement and competitive benchmarking rather than relying on their own send metrics alone.

SparkPost is now Bird Email. Bird acquired SparkPost in 2021 and folded it into a single platform for email, SMS, WhatsApp, and voice. The sending and deliverability engine is the one SparkPost built.

Yes, as Bird Email. New projects build on the Bird Email API, and the underlying deliverability engine is the same one SparkPost ran.

Existing SparkPost customers keep their service. For new work you build on the Bird Email API, which gives you the same deliverability plus SMS, WhatsApp, and voice on one set of keys.

Bird exposes a modern email API with SDKs in every major runtime. Starting fresh, you integrate against the Bird Email API; the docs cover sending, templates, sending domains, and webhooks.

To add the deliverability engine behind roughly 40% of the world's commercial email to its multichannel platform, so one API could carry email next to SMS, WhatsApp, and voice.

Momentum is Bird's enterprise email infrastructure platform that handles high-volume sending with customizable workflows and real-time routing. It's designed to scale with your needs while maintaining optimal performance.

Momentum combines advanced authentication techniques, spam monitoring, and dynamic flow control to maximize inbox placement. Our Intelligence Router ensures optimal routing and delivery.

Enterprise-grade TLS encryption, comprehensive compliance tools, and granular access controls protect your email infrastructure and ensure secure message transport.

Full Unicode support (SMTPUTF8) enables global sending with proper handling of international character sets and region-specific requirements for worldwide reach.

Momentum offers fully customizable workflows, routing rules, and delivery parameters through the Policy Manager to match your specific business needs.

The Intelligence Router provides instant visibility across all data sources with real-time alerts and dynamic delivery adjustments for optimal performance.

Adaptive Delivery is Momentum's automatic traffic shaping. It watches how each mailbox provider responds to your mail and adjusts in real time, throttling, deferring, or briefly pausing a stream to protect your reputation, then ramping back up once things clear. You reach the inbox without manually babysitting send rates for every provider.

Both. Momentum runs on your own servers, on any major cloud, or split across the two, so you can match it to your infrastructure, cost, and compliance needs and change that mix over time.

Yes. Recent releases keep it current with modern operating systems, TLS 1.3, and up-to-date security and SMTP standards, and expose message events through real-time APIs you can feed into your own reporting and automation.

Yes. PowerMTA can relay traffic to the hosted Bird Email API while still delivering the rest straight from your own servers. It's the simplest way to try the hosted platform, or to migrate gradually, without moving everything at once.

Virtual MTAs let you run several independent sending streams inside one PowerMTA instance, each with its own IPs, reputation, and limits. Use them to keep transactional and marketing mail, or different customers, cleanly separated so one stream's problems never affect another.

Yes. PowerMTA runs on infrastructure you own, so the IPs it sends from are yours to manage. If you relay some traffic to the hosted platform, that portion can use Bird's IPs or your dedicated IPs there, while everything you keep on-prem stays entirely under your control.

Email deliverability measures whether your emails reach subscribers' inboxes. Inbox Tracker measures this through actual consumer behavior data, licensed mailbox placement data, and traditional seeds.

Inbox Tracker monitors spam trap hits, ISP-level placement, and provides daily breakdowns showing where your emails are landing: inbox, spam, or blocked.

DMARC is an email authentication protocol. Inbox Tracker includes DMARC performance monitoring with real-time alerts to protect your domain reputation.

Inbox Tracker's Reputation Advisor checks 5 critical areas of your email program and provides automated reporting to help maintain a strong sender reputation.

Spam traps are email addresses used to identify spammers. Inbox Tracker provides daily break-downs of spam trap hits to help maintain good inbox placement.

Inbox Tracker monitors campaign performance at the ISP-level in real-time, alerting you to deliverability issues before they harm your sending domain reputation.

It combines several sources: licensed mailbox data that shows where your mail actually lands for real recipients, seed accounts that test placement across different scenarios, and a direct Google Postmaster connection for Gmail's own reputation and authentication view. Using them together catches issues any single source would miss.

Different mailbox providers weigh different things, and each kind of data answers a different question: real mailbox data shows the outcome, Postmaster data shows Gmail's reasoning, and seeds test specific scenarios. Relying on just one leaves blind spots and false alarms; combining them gives you a placement picture you can act on.

We actively track millions of emails daily across 250,000+ brands in over 100 industries, providing real-time insights into deliverability and engagement.

You can view competitor email journeys, campaign frequency, messaging strategies, and performance metrics to benchmark your own campaigns.

Monitor market changes and competitor activities to plan ahead for seasonal campaigns and identify successful strategies in your industry.

Compare audience size, email activity, campaign performance, and engagement rates against other brands in your industry.

Our system tracks over 1 million emails daily, providing current insights into competitor performance and industry trends.

We track email marketing across 100+ industries, allowing you to benchmark against direct competitors and learn from other sectors.

Often, yes. Competitive Tracker can surface the sending platform or service behind a competitor's email, which is useful for competitive research and for sales teams sizing up how a prospect's rivals run their programs.

Providers treat that like address harvesting and will rate-limit or blocklist you for it, and the results are unreliable: a server can accept an address at the handshake that still won't deliver, and greylisting makes real addresses look invalid. Checking against delivery history avoids both the risk and the false answers.

Your call. Neutral means the address is well-formed, has a real mail server, and has never hard-bounced, but we haven't yet seen a delivery or engagement event for it. It's low risk, not suspect. Send to it if you're growth-focused, or hold it until you see engagement if you'd rather play safe.

On a signup form, show the suggested correction so the person can fix it before submitting, which recovers a lead that would otherwise bounce. In a batch list, separate the typos out and confirm or drop them, but don't send to the misspelled address.