Email API shortlist
Choose the right email API for your workload
Deliver transactional emails, run marketing campaigns, and manage AI agent mailboxes from one platform. Ship and operate email workflows through the REST API, SDKs, CLI, and Bird MCP.
This shortlist matches each provider to the workload it fits best and spells out the trade-offs before you integrate. Every pricing table compares published rates side by side and separates a spendable Bird balance from fixed monthly send allowances.
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Which email API fits your application?
Choose Bird when you want transactional delivery, marketing broadcasts, and conversational agent inboxes in a single account. Use the table below to see where other providers fit specific workloads. These recommendations reflect documented product capabilities rather than inbox-placement rankings.
| Provider | Choose for | Check before choosing |
|---|---|---|
| Bird | Transactional email, marketing campaigns, and agent mailboxes in one workspace, complete with reusable templates, audience targeting, threaded replies, and inbound sender rules. | Plan how you will map message streams and suppressions when migrating an existing app, since Bird’s message category tags traffic rather than isolating infrastructure. Review the idempotent retry window and single-address email lookup guide. |
| Resend | React Email templates rendered and sent directly from the Node SDK. | Dedicated IPs require the Scale plan and an add-on, while managed IP pools scale dynamically without exposing the underlying IP addresses. |
| Postmark | Message Streams that keep transactional receipts and broadcast traffic on separate IP ranges. | Safe send retries require your own deduplication logic: Postmark does not support request idempotency keys and recommends combining status-code checks with delivery webhooks. |
| Mailgun | Inbound Routes that filter incoming emails and forward or store matching messages. | Mailgun’s Inbox Placement test key prevents duplicate seed tests rather than deduplicating customer email retries. |
| Amazon SES | Applications already running on AWS that manage email sending, verified identities, configuration sets, and suppression lists through IAM and the AWS CLI. | AWS pricing bills send volume, account tiers, attachment data transfer, and optional add-ons separately instead of bundling a monthly send allowance. |
| SendGrid | Subusers that isolate sending domains, analytics, team permissions, and credit limits under a parent account. | Inbound Parse posts incoming mail and attachments to your webhook URL, leaving thread state and message storage up to your application. |
| MailerSend | Hosted MCP tools and a CLI for sending email and SMS and managing domains, templates, and recipients. | Dedicated IPs are gated by monthly sending volume and manual review on qualifying plans. |
| Brevo | MCP tools for managing CRM contacts, marketing campaigns, templates, and domains. | Batch retry protection covers the entire multi-version batch request at once and expires after 30 minutes. |
How do Bird, AgentMail and Nylas compare for mailbox state?
All three products provision hosted inboxes that store incoming messages and track reply threads for software and AI agents. The Nylas column covers Agent Accounts, which give an autonomous agent its own mailbox without OAuth access to an employee inbox.
| Mailbox requirement | Bird | AgentMail and Nylas Agent Accounts |
|---|---|---|
| Parsed webhook | The inbound mail webhook delivers mailbox, thread, and message identifiers alongside sender details, recipients, and quote-stripped reply text with a flag when long bodies are truncated. | AgentMail: Inbound mail events include message and thread payloads, though plain-text and HTML availability depends on what the sender transmitted. Nylas: Inbound notifications announce newly stored mail, and large payloads omit the body so your app fetches the full message via the API. |
| Stored content | Stored mailbox messages retain headers, extracted reply text, and attachments so agents can read context on demand, while full bodies and inbound raw MIME follow configurable retention windows. | AgentMail: Message retrieval returns stored content and reply text stripped of quoted history, with separate calls for raw MIME and attachments. Nylas: Agent Account mailboxes organize stored messages in folders under policy-defined storage and retention limits. |
| Address provisioning | Provision a mailbox in one call on a generated address for instant testing, or bind it to your own receiving-enabled custom domain. | AgentMail: Create an inbox on the default domain or a verified custom domain, with optional auto-generated usernames. Nylas: Provision a hosted Agent Account via the API or CLI without user OAuth on either a custom domain or a Nylas trial domain. |
| Thread and reply state | Conversation threads track participants and unread counts automatically: replying appends to the existing thread while composing starts a new conversation. | AgentMail: Reply actions keep outbound responses inside the same retrievable thread. Nylas: Threaded replies set standard reply headers automatically and attach the sent message to the active Agent Account thread. |
| Sender rules | Receive policies and sender rules restrict an inbox to existing threads or approved senders. Blocked messages stay inspectable in a separate folder without triggering webhooks or agent runs, or can be dropped outright. | AgentMail: Allow and block lists filter outbound sends, new inbound mail, and replies at the organization, pod, or inbox level. Nylas: Workspace rules govern inbound and outbound mail separately and reject blocked senders during the SMTP handshake before storage. |
| Agent operations | CLI commands and MCP tools let agents create mailboxes, read conversation threads, and send replies, while mailbox management APIs configure receive policies and sender allowlists. | AgentMail: Hosted MCP tools create inboxes, read threads, send messages, and reply. Nylas: Agent Account CLI and API workflows provision accounts, send mail, and read replies using an account grant identifier. |
What gives Bird the advantage?
Bird pairs its own MTA and IP-reputation network with campaign management and programmable agent inboxes. Engineering and growth teams work from the same REST API, SDKs, CLI, and MCP tools rather than stitching together separate transactional, marketing, and inbound vendors.
| Capability | Bird’s advantage | What to evaluate |
|---|---|---|
| Deliverability heritage | Bird acquired SparkPost in 2021, and its sending network delivers roughly 40% of the world’s commercial email. | Bird’s Momentum MTA adapts throughput per mailbox provider in real time, while dedicated IPs and pools automate IP warm-up with shared-pool overflow. |
| Agent tooling | Bird’s hosted MCP server lets AI agents send email and manage domains, templates, and inboxes directly, while the Bird CLI and typed SDKs bring the same operations to terminals and application code. | Test the exact operations your automation or coding agent will run, including error recovery. Bird’s CLI outputs structured JSON and semantic exit codes so scripts and agents can branch reliably. |
| Mailboxes | Bird’s agent mailboxes give support workflows and AI agents dedicated email addresses, grouped conversation threads, quote-stripped replies, and sender filtering. | Decide whether your app only needs a stateless inbound webhook or a persistent inbox that tracks threads, stores messages, and blocks unwanted senders before waking your agent. |
Where is each provider a good fit?
Weigh each provider’s core strength against the operational work it leaves to your team. Every head-to-head guide below compares the sending stack, agent tooling, inbound handling, migration steps, and published pricing.
Bird
Transactional email, campaigns and agent inboxes. Bird runs its own global sending infrastructure for transactional receipts and audience-targeted marketing broadcasts, and also licenses PowerMTA for on-premises delivery. Programmable agent mailboxes handle inbound threads, replies, and sender rules in the same workspace. When migrating, map your current provider’s stream separation and suppression lists into Bird.
SendGrid
Subusers and established sending workflows SendGrid subusers partition sending reputation, permissions, and credit caps across business units, and its CLI supports basic terminal sends. Because Inbound Parse forwards raw parsed email to your webhook without storing threads, inventory your inbound webhook handlers before migrating.
Amazon SES
Email inside an AWS application The AWS CLI and AWS MCP Server let teams manage identities, configuration sets, and sends using existing IAM roles and SigV4 authentication. SES receiving rules drop incoming mail into S3 buckets or SNS topics, leaving parsing, storage, and reply threading to your own AWS services.
Mailgun
Inbound message routing Mailgun Routes match incoming mail against header or recipient expressions and trigger forwarding or temporary storage. Its open-source MCP server exposes sending, domain, route, template, and deliverability tools, though you host and run the server process yourself.
Postmark
Transactional and broadcast separation Postmark Message Streams keep transactional mail and broadcast traffic on separate IP pools by default. Postmark provides an open-source MCP server and CLI for templates and delivery inspection, while its inbound webhook posts parsed JSON to your app without hosted mailbox state.
MailerSend
Email operations through CLI and MCP MailerSend’s hosted MCP server and CLI cover email and SMS sending alongside domain, template, webhook, and suppression management. When migrating, keep temporary On Hold soft-bounce suppressions separate so 72-hour holds do not become permanent blocks.
Brevo
Contact and campaign operations Brevo’s MCP server connects AI tools to CRM contacts, campaigns, templates, and domains, while its CLI focuses on OAuth app setup and local testing. Note that batch retry deduplication applies to the entire batch payload for 30 minutes.
Resend
React templates and receiving Resend’s Node SDK renders React Email components directly on send, and its receiving API exposes inbound content, attachments, and reply headers. Resend also offers a hosted MCP server and CLI for sending and domain management.
How do the published email plans compare?
Expand any provider below to compare Bird’s live rates against that vendor’s published plans at matching monthly volumes. Pay attention to how billing works: a Bird funding deposit stays in your workspace as spendable balance across channels, whereas a bundled tier charges a flat fee for a fixed monthly email cap. Each competitor figure links to its pricing page with the date it was verified.
Bird / Amazon SES
Bird paid plans add a monthly deposit to a shared balance. Transactional sends use the plan's rate. The comparison below assumes the balance is used only for email; other usage and add-ons cost extra.
Pricing verdict: Not comparable. At each rival allowance, Bird's estimated monthly cash requirement is the greater of the paid plan deposit and transactional usage at its published rate. The Free plan uses its included allowance where available. Deposits are spendable balance, not an extra fee. Only matching volumes and currencies with complete rates affect the verdict.
| Bird tier | Paid-plan allowance | Bird | Amazon SES |
|---|---|---|---|
| Free | 1,000 | 4 plans at this volumeExpand to compare every option and its billing terms. Matching volume À la carte outbound email: $0.10 / 1,000 emails 1,000 emails No monthly fee; uncapped usage rate, not a monthly allowance; attachment data charged separately. as published Matching volume Essentials: $0.16 per 1,000 emails 1,000 emails Usage rate for the 0–10M emails/month band, not a monthly allowance. No account fee; attachment data charged separately. Tiered rates apply marginally; higher-volume rates are on the publisher page. as published Matching volume Pro: $0.22 per 1,000 emails 1,000 emails Usage rate for the 0–10M emails/month band, not a monthly allowance. $105 per account per region per month; attachment data charged separately. Tiered rates apply marginally; higher-volume rates are on the publisher page. as published Matching volume Enterprise: $0.23 per 1,000 emails 1,000 emails Usage rate for the 0–10M emails/month band, not a monthly allowance. $500 per account per region per month; attachment data charged separately. Tiered rates apply marginally; higher-volume rates are on the publisher page. as published | |
| Email Startup | None on paid plans | €15 / month to shared balance (EUR); email usage charged separately $15 / month to shared balance (USD); email usage charged separately | See published plans below |
| Email Growth | None on paid plans | €250 / month to shared balance (EUR); email usage charged separately $250 / month to shared balance (USD); email usage charged separately | See published plans below |
| Email Scale 1,000 | None on paid plans | €1,000 / month to shared balance (EUR); email usage charged separately $1,000 / month to shared balance (USD); email usage charged separately | See published plans below |
| Email Scale 2,500 | None on paid plans | €2,500 / month to shared balance (EUR); email usage charged separately $2,500 / month to shared balance (USD); email usage charged separately | See published plans below |
| Email Scale 5,000 | None on paid plans | €5,000 / month to shared balance (EUR); email usage charged separately $5,000 / month to shared balance (USD); email usage charged separately | See published plans below |
| Email Scale 10,000 | None on paid plans | €10,000 / month to shared balance (EUR); email usage charged separately $10,000 / month to shared balance (USD); email usage charged separately | See published plans below |
Amazon SES: Published plans
1,000 emails
No monthly fee; uncapped usage rate, not a monthly allowance; attachment data charged separately.
as published
1,000 emails
Usage rate for the 0–10M emails/month band, not a monthly allowance. No account fee; attachment data charged separately. Tiered rates apply marginally; higher-volume rates are on the publisher page.
as published
1,000 emails
Usage rate for the 0–10M emails/month band, not a monthly allowance. $105 per account per region per month; attachment data charged separately. Tiered rates apply marginally; higher-volume rates are on the publisher page.
as published
1,000 emails
Usage rate for the 0–10M emails/month band, not a monthly allowance. $500 per account per region per month; attachment data charged separately. Tiered rates apply marginally; higher-volume rates are on the publisher page.
as published
Bird / Brevo
Bird paid plans add a monthly deposit to a shared balance. Transactional sends use the plan's rate. The comparison below assumes the balance is used only for email; other usage and add-ons cost extra.
Pricing verdict: Mixed by volume. At each rival allowance, Bird's estimated monthly cash requirement is the greater of the paid plan deposit and transactional usage at its published rate. The Free plan uses its included allowance where available. Deposits are spendable balance, not an extra fee. Only matching volumes and currencies with complete rates affect the verdict.
| Emails per month | Bird plan and monthly cash required | Brevo |
|---|---|---|
| 5,000 | Email Startup: €15 (EUR) | |
| 50,000 | Email Startup: €18.000000000000004 (EUR) | |
| 100,000 | Email Startup: €36.00000000000001 (EUR) | |
| 250,000 | Email Startup: €90.00000000000001 (EUR) | |
| 500,000 | Email Startup: €180.00000000000003 (EUR) | |
| 150,000 | Email Startup: €54.00000000000001 (EUR) | |
| 1,000,000 | Email Startup: €360.00000000000006 (EUR) | |
| 3,000,000 | Email Scale 1,000: €1,000 (EUR) | Professional: €1,713.00/month 3,000,000 emails Monthly billing; optional add-ons excluded. as published |
Brevo: Published plans
3,000,000 emails
Monthly billing; optional add-ons excluded.
as published
Bird / MailerSend
Bird paid plans add a monthly deposit to a shared balance. Transactional sends use the plan's rate. The comparison below assumes the balance is used only for email; other usage and add-ons cost extra.
Pricing verdict: Mixed by volume. At each rival allowance, Bird's estimated monthly cash requirement is the greater of the paid plan deposit and transactional usage at its published rate. The Free plan uses its included allowance where available. Deposits are spendable balance, not an extra fee. Only matching volumes and currencies with complete rates affect the verdict.
| Emails per month | Bird plan and monthly cash required | MailerSend |
|---|---|---|
| 500 | Free: $0 (USD) | |
| 5,000 | Email Startup: $15 (USD) | |
| 50,000 | Email Startup: $20 (USD) | |
| 100,000 | Email Startup: $40 (USD) | |
| 250,000 | Email Startup: $100 (USD) | |
| 500,000 | Email Startup: $200 (USD) | |
| 1,000,000 | Email Startup: $400 (USD) | |
| 2,000,000 | Email Startup: $800 (USD) |
MailerSend: Published plans
Bird / Mailgun
Bird paid plans add a monthly deposit to a shared balance. Transactional sends use the plan's rate. The comparison below assumes the balance is used only for email; other usage and add-ons cost extra.
Pricing verdict: Bird. At each rival allowance, Bird's estimated monthly cash requirement is the greater of the paid plan deposit and transactional usage at its published rate. The Free plan uses its included allowance where available. Deposits are spendable balance, not an extra fee. Only matching volumes and currencies with complete rates affect the verdict.
| Emails per month | Bird plan and monthly cash required | Mailgun |
|---|---|---|
| 50,000 | Email Startup: $20 (USD) | |
| 100,000 | Email Startup: $40 (USD) | |
| 250,000 | Email Startup: $100 (USD) | |
| 500,000 | Email Startup: $200 (USD) | |
| 1,000,000 | Email Startup: $400 (USD) | |
| 2,500,000 | Email Startup: $1,000 (USD) |
Mailgun: Published plans
Bird / Postmark
Bird paid plans add a monthly deposit to a shared balance. Transactional sends use the plan's rate. The comparison below assumes the balance is used only for email; other usage and add-ons cost extra.
Pricing verdict: Mixed by volume. At each rival allowance, Bird's estimated monthly cash requirement is the greater of the paid plan deposit and transactional usage at its published rate. The Free plan uses its included allowance where available. Deposits are spendable balance, not an extra fee. Only matching volumes and currencies with complete rates affect the verdict.
| Emails per month | Bird plan and monthly cash required | Postmark |
|---|---|---|
| 100 | Free: $0 (USD) | |
| 10,000 | Email Startup: $15 (USD) | |
| 50,000 | Email Startup: $20 (USD) | |
| 125,000 | Email Startup: $50 (USD) | |
| 300,000 | Email Startup: $120 (USD) | |
| 700,000 | Email Startup: $280 (USD) | |
| 1,500,000 | Email Startup: $600 (USD) | Basic: $775.00/mo 1,500,000 emails Monthly billing; volume covers emails sent and received. as published |
Postmark: Published plans
1,500,000 emails
Monthly billing; volume covers emails sent and received.
as published
10,000 emails
Monthly billing; volume covers emails sent and received.
as published
50,000 emails
Monthly billing; volume covers emails sent and received.
as published
125,000 emails
Monthly billing; volume covers emails sent and received.
as published
300,000 emails
Monthly billing; volume covers emails sent and received.
as published
700,000 emails
Monthly billing; volume covers emails sent and received.
as published
1,500,000 emails
Monthly billing; volume covers emails sent and received.
as published
Bird / Resend
Bird paid plans add a monthly deposit to a shared balance. Transactional sends use the plan's rate. The comparison below assumes the balance is used only for email; other usage and add-ons cost extra.
Pricing verdict: Mixed by volume. At each rival allowance, Bird's estimated monthly cash requirement is the greater of the paid plan deposit and transactional usage at its published rate. The Free plan uses its included allowance where available. Deposits are spendable balance, not an extra fee. Only matching volumes and currencies with complete rates affect the verdict.
| Emails per month | Bird plan and monthly cash required | Resend |
|---|---|---|
| 3,000 | Email Startup: $15 (USD) | |
| 50,000 | Email Startup: $20 (USD) | |
| 100,000 | Email Startup: $40 (USD) | |
| 200,000 | Email Startup: $80 (USD) | |
| 500,000 | Email Startup: $200 (USD) | |
| 1,000,000 | Email Startup: $400 (USD) | |
| 2,500,000 | Email Startup: $1,000 (USD) |
Resend: Published plans
Bird / SendGrid
Bird paid plans add a monthly deposit to a shared balance. Transactional sends use the plan's rate. The comparison below assumes the balance is used only for email; other usage and add-ons cost extra.
Pricing verdict: Not comparable. At each rival allowance, Bird's estimated monthly cash requirement is the greater of the paid plan deposit and transactional usage at its published rate. The Free plan uses its included allowance where available. Deposits are spendable balance, not an extra fee. Only matching volumes and currencies with complete rates affect the verdict.
SendGrid: Published plans
50,000 emails
Monthly billing; published volume range is 50,000 to 100,000 emails. Taxes and overages may apply.
as published
100,000 emails
Monthly billing; published volume range is 100,000 to 2,500,000 emails. Taxes and overages may apply.
as published
How should you choose an email API?
How does Bird compare email API providers?
How should I compare email API costs?
How should I test an email API before switching?
How do I migrate to Bird’s email API?
Put it into practice.
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