What is the difference between Project Blue and Sendblue?

Project Blue supports 42 of the 77 features compared here, and Sendblue supports 58. Project Blue adds WhatsApp and Slack. Sendblue adds threaded replies, read receipts, rich link previews, location sharing and iMessage apps.

How much do Project Blue and Sendblue cost?

Project Blue: Flat per-line pricing: $166 a month per line billed annually or $199 a month per line on a 12-month plan, with a free trial on a shared line. Sendblue: A free sandbox for testing, the AI Agent plan at $100 per line per month for inbound-first use, and custom Enterprise pricing for outbound and volume.

Does Sendblue support WhatsApp?

Sendblue does not support WhatsApp.

Does Sendblue support Slack?

Sendblue does not list Slack on its site or in its docs.

Project Blue vs Sendblue: Features, Pricing and Differences

Feature comparison

Feature	Project Blue	Sendblue
iMessage messaging
iMessage	Supported	Supported
Group chats	SupportedSend to groups of 2 to 32 by API. Not on trial accounts, and group sends do not sync to the CRM.	BetaGroup API is in beta on select plans. AI Agent plan can only reply in existing groups.
Group management	PartialGroups are created by sending to a set of numbers. No add or remove member endpoints documented.	BetaAdd and remove participants in iMessage groups via the beta groups API.
Group name and photo	PartialgroupName can be set when a group is created. No group photo documented.	SupportedRename groups and set group photos on supported lines.
Mentions	Not listed	Not listed
Tapbacks	PartialSend or remove the six classic tapbacks on inbound iMessages. Receiving reactions is not documented.	PartialSend classic tapbacks or any emoji. No inbound reaction events documented.
Threaded replies	Not listed	Supportedreply_to on V2 iMessage lines, in direct and group chats.
Typing indicators	PartialSend only, iMessage only, into an existing conversation. Inbound typing events not documented.	SupportedSend and receive. iMessage 1:1 only, not in groups.
Read receipts	Not listed	PartialCan mark chats read (1:1). Outbound statuses stop at DELIVERED, with no read status.
Edit and unsend	Not listed	Not supportedDocs say editing is not supported via API and delete does not unsend.
Message effects	Supported4 bubble and 9 screen effects through the effect field. iMessage only.	Supported13 send_style values.
Animated text effects	Not listed	Not listed
Stickers	Not listed	Not listed
Formatted text	Not listed	Not listed
Attachments	SupportedImages, videos and vCards by URL.	SupportedUp to 100MB on iMessage, 5MB on SMS.
Live Photos	Not listed	Not listed
Rich link previews	Not listed	PartialDocs say links expand only after the recipient saves your contact.
Voice messages	SupportedAudio files sent as voice memos, plus AI text-to-speech voice memos.	SupportedSend .caf files to render as inline voice notes.
Contact cards	SupportedVCF files through mediaAttachmentUrl.	SupportedSend .vcf files via media_url.
Polls	Not listed	Not listed
Chat backgrounds	Not listed	Not listed
Location sharing	Not listed	SupportedFind My request, read and live watch. Dedicated iMessage lines only.
iMessage apps	Not listed	SupportedApp Cards for your own Messages extension. V2 lines, not on the free plan.
Live app cards	Not listed	PartialUpdates go out as new messages in the same App Card session; Sendblue says the original is not edited.
Sender name and photo	SupportedSet, read and share a line's Share Name and Photo card by API.	SupportedName and Photo Sharing profile per line, shared into direct iMessage chats.
FaceTime calls	PartialFaceTime Audio only, outbound and inbound, on FaceTime-enabled accounts. Not on trials.	PartialOutbound FaceTime audio over WebRTC (Agora). Needs a purchased FaceTime line.
Delivery status	PartialMessages carry a status field such as delivered. Webhooks cover only inbound and outbound messages.	SupportedStatus callbacks from REGISTERED through SENT or DELIVERED.
iMessage availability check	Supported	SupportedLookup API checks a phone number or email for iMessage.
Focus and Notify Anyway	Not listed	Not listed
Numbers and delivery
Managed lines	SupportedNo iPhone, Mac or SIM needed. Lines are set up remotely, usually within one business day.	Supported
Dedicated numbers	SupportedA dedicated line per rep, never shared. New lines are requested by API and provisioned by the team.	Supported
Shared numbers	PartialTrial accounts only: a shared line that can reach verified numbers.	SupportedFree sandbox uses a shared number with verified contacts only.
Bring your own number	SupportedExisting numbers can be ported to Project Blue's carrier partner.	PartialOnly by porting the number in, which adds 3 to 5 days.
Line pooling	SupportedSends without lineId are load balanced across your lines.	SupportedNumber pooling with sticky sending. Automatic line selection needs account enablement.
SMS fallback	SupportedFalls back to SMS from the same line when iMessage is unavailable.	Supported
RCS fallback	Not listedHomepage describes fallback from iMessage to WhatsApp to SMS. RCS fallback is not described.	SupportediMessage, then RCS, then SMS. RCS on V2 lines.
Outbound-first messaging	SupportedLines are sold as outbound-ready. Guidelines rule out mass outbound iMessage.	SupportedFull outbound on Enterprise or Blue Ocean; Free and AI Agent plans are inbound-first
Calls on the iMessage number	SupportedDialer and FaceTime Audio calls from the same number as the messaging line.	SupportedDashboard calls and FaceTime from the texting number; API calls via your Twilio caller ID.
Other channels
SMS	Supported	Supported
RCS	PartialRCS for rich media was rolled out in 2026. The API lists RCS as inbound only.	SupportedV2 lines.
WhatsApp	PartialHomepage lists WhatsApp as a fallback step. No WhatsApp option in the API, and llms.txt says it is not a WhatsApp API.	Not supportedNot offered
Telegram	Not supportedNot offered	Not supported
Slack	PartialSlack notifications for inbound replies. Not a messaging channel.	Not listed
Email	Not supportedDeveloper page says it is not a general email API.	Not supportedNot offered. iMessage can be sent to Apple ID email addresses.
Phone calls	SupportedCloud dialer with inbound, outbound, routing, recording and voicemail, plus a browser calling SDK.	PartialNo native calling API. Dashboard calls, outbound via your Twilio caller ID, inbound forwarding.
Apple Messages for Business	Not supportedNot offered	Not supportedNot offered
Unified channel API	PartialOne send endpoint covers iMessage and SMS. Calls and FaceTime use separate endpoints.	SupportedOne API for iMessage, RCS and SMS, the only channels offered.
Developer tools
REST API	SupportedREST API with Bearer keys and an OpenAPI spec.	Supported
TypeScript SDK	Partial@tryprojectblue/dialer is a browser SDK for phone calls only. No messaging SDK.	Supportedsendblue on npm.
Python SDK	Not listed	Supportedsendblue on PyPI.
Other SDKs	Not listed	PartialGo, Rust and Ruby packages, listed as community packages.
CLI	Not listed	Supported@sendblue/cli: signup, messaging, contacts and webhooks.
Webhooks	SupportedInbound and outbound message events and inbound FaceTime call events.	Supported
Signed webhooks	Not listedWebhook docs do not mention signatures.	PartialSends your shared secret in an sb-signing-secret header. No HMAC signature.
MCP server	SupportedRemote MCP server with OAuth 2.1, plus an optional Claude Code plugin.	Supportedsendblue-api-mcp via npx.
Open source	PartialThe dialer SDK is MIT licensed on npm. The platform is closed.	PartialSDKs and CLI are MIT or Apache-2.0 on GitHub. The messaging platform is closed.
Self-hosting	Not listedHosted service on Project Blue lines. Self-hosting is not mentioned.	Not listedSold as a hosted service on Sendblue's Apple devices; self-hosting is not mentioned.
Local testing	Not listedTrial accounts send real messages to verified numbers; docs say they are not a simulator.	Not listed
Custom channel providers	Not listed	Not listed
Event replay	Not supportedDocs say webhooks have no retries and failed deliveries are not replayed.	PartialNo replay. Docs say to repair gaps by listing messages updated since a timestamp.
OpenTelemetry	Not listed	Not listed
No-code integrations	SupportedGoHighLevel conversation provider with workflow actions and triggers. llms.txt also lists Zapier.	SupportedZapier, Make and GoHighLevel. Docs FAQ says n8n resources are coming soon.
CRM integrations	SupportedHubSpot and Close CRM. Salesforce is not listed.	SupportedGoHighLevel, HubSpot, Salesforce, Close and Monday.com.
Built for AI agents
Agent framework	Not listed	PartialNo own framework. Maintains a Vercel Chat SDK adapter.
Agent framework integrations	Not listed	SupportedSendblue-maintained Vercel Chat SDK adapter.
Streaming replies	Not listed	Not supportedDocs say message editing is not supported via the API.
Agent group chats	Not listed	BetaA line can add another of your own dedicated lines to a group, via the beta groups API.
Human handoff	PartialReps reply in the CRM inbox and can join group threads. No agent handoff controls documented.	SupportedShared team inboxes with assignment, and agents that escalate to a rep.
Audit logs	Not listed	PartialSecurity page says all API requests are logged. No customer-facing audit log documented.
Message history API	SupportedList and get messages, inbound and outbound, with filters.	Supported
Plans and compliance
Free plan	PartialFree trial on a shared line to verified numbers. Some endpoints are off on trial.	SupportedFree sandbox: shared number, up to 10 verified contacts, no webhooks.
Public pricing	Supported$166/month per line billed annually, or $199/month per line on a 12-month plan.	SupportedAI Agent plan at $100/mo per line. Enterprise is custom.
No per-message fees	SupportedFlat per-line pricing with unlimited texting under fair use.	Supported
Uptime SLA	Not listedSite cites a 99.9% uptime record and a public status page. No contractual SLA found.	Supported99.99% uptime SLA on the Enterprise plan
Isolated infrastructure	PartialEach rep gets a dedicated line that is never shared. Other infrastructure is not described.	SupportedA dedicated HIPAA instance for HIPAA customers
SOC 2 Type II	Not listed	SupportedSOC 2 Type II, report on request.
GDPR	PartialPrivacy policy lists GDPR and UK GDPR rights. No DPA found.	SupportedPrivacy policy says Sendblue adheres to GDPR. DPAs on request.

Feature

Project Blue

Sendblue

iMessage messaging

iMessage

Group chats

Send to groups of 2 to 32 by API. Not on trial accounts, and group sends do not sync to the CRM.

BetaGroup API is in beta on select plans. AI Agent plan can only reply in existing groups.

Group management

PartialGroups are created by sending to a set of numbers. No add or remove member endpoints documented.

BetaAdd and remove participants in iMessage groups via the beta groups API.

Group name and photo

PartialgroupName can be set when a group is created. No group photo documented.

Rename groups and set group photos on supported lines.

Mentions

Not listed

Tapbacks

PartialSend or remove the six classic tapbacks on inbound iMessages. Receiving reactions is not documented.

PartialSend classic tapbacks or any emoji. No inbound reaction events documented.

Threaded replies

Not listed

reply_to on V2 iMessage lines, in direct and group chats.

Typing indicators

PartialSend only, iMessage only, into an existing conversation. Inbound typing events not documented.

Send and receive. iMessage 1:1 only, not in groups.

Read receipts

Not listed

PartialCan mark chats read (1:1). Outbound statuses stop at DELIVERED, with no read status.

Edit and unsend

Not listed

Not supportedDocs say editing is not supported via API and delete does not unsend.

Message effects

4 bubble and 9 screen effects through the effect field. iMessage only.

13 send_style values.

Animated text effects

Not listed

Stickers

Not listed

Formatted text

Not listed

Attachments

Images, videos and vCards by URL.

Up to 100MB on iMessage, 5MB on SMS.

Live Photos

Not listed

Rich link previews

Not listed

PartialDocs say links expand only after the recipient saves your contact.

Voice messages

Audio files sent as voice memos, plus AI text-to-speech voice memos.

Send .caf files to render as inline voice notes.

Contact cards

VCF files through mediaAttachmentUrl.

Send .vcf files via media_url.

Polls

Not listed

Chat backgrounds

Not listed

Location sharing

Not listed

Find My request, read and live watch. Dedicated iMessage lines only.

iMessage apps

Not listed

App Cards for your own Messages extension. V2 lines, not on the free plan.

Live app cards

Not listed

PartialUpdates go out as new messages in the same App Card session; Sendblue says the original is not edited.

Sender name and photo

Set, read and share a line's Share Name and Photo card by API.

Name and Photo Sharing profile per line, shared into direct iMessage chats.

FaceTime calls

PartialFaceTime Audio only, outbound and inbound, on FaceTime-enabled accounts. Not on trials.

PartialOutbound FaceTime audio over WebRTC (Agora). Needs a purchased FaceTime line.

Delivery status

PartialMessages carry a status field such as delivered. Webhooks cover only inbound and outbound messages.

Status callbacks from REGISTERED through SENT or DELIVERED.

iMessage availability check

Lookup API checks a phone number or email for iMessage.

Focus and Notify Anyway

Not listed

Numbers and delivery

Managed lines

No iPhone, Mac or SIM needed. Lines are set up remotely, usually within one business day.

Dedicated numbers

A dedicated line per rep, never shared. New lines are requested by API and provisioned by the team.

Shared numbers

PartialTrial accounts only: a shared line that can reach verified numbers.

Free sandbox uses a shared number with verified contacts only.

Bring your own number

Existing numbers can be ported to Project Blue's carrier partner.

PartialOnly by porting the number in, which adds 3 to 5 days.

Line pooling

Sends without lineId are load balanced across your lines.

Number pooling with sticky sending. Automatic line selection needs account enablement.

SMS fallback

Falls back to SMS from the same line when iMessage is unavailable.

RCS fallback

Not listedHomepage describes fallback from iMessage to WhatsApp to SMS. RCS fallback is not described.

iMessage, then RCS, then SMS. RCS on V2 lines.

Outbound-first messaging

Lines are sold as outbound-ready. Guidelines rule out mass outbound iMessage.

Full outbound on Enterprise or Blue Ocean; Free and AI Agent plans are inbound-first

Calls on the iMessage number

Dialer and FaceTime Audio calls from the same number as the messaging line.

Dashboard calls and FaceTime from the texting number; API calls via your Twilio caller ID.

Other channels

SMS

RCS

PartialRCS for rich media was rolled out in 2026. The API lists RCS as inbound only.

V2 lines.

PartialHomepage lists WhatsApp as a fallback step. No WhatsApp option in the API, and llms.txt says it is not a WhatsApp API.

Not supportedNot offered

Not supported

Slack

PartialSlack notifications for inbound replies. Not a messaging channel.

Not listed

Not supportedDeveloper page says it is not a general email API.

Not supportedNot offered. iMessage can be sent to Apple ID email addresses.

Phone calls

Cloud dialer with inbound, outbound, routing, recording and voicemail, plus a browser calling SDK.

PartialNo native calling API. Dashboard calls, outbound via your Twilio caller ID, inbound forwarding.

Apple Messages for Business

Not supportedNot offered

Unified channel API

PartialOne send endpoint covers iMessage and SMS. Calls and FaceTime use separate endpoints.

One API for iMessage, RCS and SMS, the only channels offered.

Developer tools

REST API

REST API with Bearer keys and an OpenAPI spec.

TypeScript SDK

Partial@tryprojectblue/dialer is a browser SDK for phone calls only. No messaging SDK.

sendblue on npm.

Python SDK

Not listed

sendblue on PyPI.

Other SDKs

Not listed

PartialGo, Rust and Ruby packages, listed as community packages.

CLI

Not listed

@sendblue/cli: signup, messaging, contacts and webhooks.

Webhooks

Inbound and outbound message events and inbound FaceTime call events.

Signed webhooks

Not listedWebhook docs do not mention signatures.

PartialSends your shared secret in an sb-signing-secret header. No HMAC signature.

MCP server

Remote MCP server with OAuth 2.1, plus an optional Claude Code plugin.

sendblue-api-mcp via npx.

Open source

PartialThe dialer SDK is MIT licensed on npm. The platform is closed.

PartialSDKs and CLI are MIT or Apache-2.0 on GitHub. The messaging platform is closed.

Self-hosting

Not listedHosted service on Project Blue lines. Self-hosting is not mentioned.

Not listedSold as a hosted service on Sendblue's Apple devices; self-hosting is not mentioned.

Local testing

Not listedTrial accounts send real messages to verified numbers; docs say they are not a simulator.

Not listed

Custom channel providers

Not listed

Event replay

Not supportedDocs say webhooks have no retries and failed deliveries are not replayed.

PartialNo replay. Docs say to repair gaps by listing messages updated since a timestamp.

OpenTelemetry

Not listed

No-code integrations

GoHighLevel conversation provider with workflow actions and triggers. llms.txt also lists Zapier.

Zapier, Make and GoHighLevel. Docs FAQ says n8n resources are coming soon.

CRM integrations

HubSpot and Close CRM. Salesforce is not listed.

GoHighLevel, HubSpot, Salesforce, Close and Monday.com.

Built for AI agents

Agent framework

Not listed

PartialNo own framework. Maintains a Vercel Chat SDK adapter.

Agent framework integrations

Not listed

Sendblue-maintained Vercel Chat SDK adapter.

Streaming replies

Not listed

Not supportedDocs say message editing is not supported via the API.

Agent group chats

Not listed

BetaA line can add another of your own dedicated lines to a group, via the beta groups API.

Human handoff

PartialReps reply in the CRM inbox and can join group threads. No agent handoff controls documented.

Shared team inboxes with assignment, and agents that escalate to a rep.

Audit logs

Not listed

PartialSecurity page says all API requests are logged. No customer-facing audit log documented.

Message history API

List and get messages, inbound and outbound, with filters.

Plans and compliance

Free plan

PartialFree trial on a shared line to verified numbers. Some endpoints are off on trial.

Free sandbox: shared number, up to 10 verified contacts, no webhooks.

Public pricing

$166/month per line billed annually, or $199/month per line on a 12-month plan.

AI Agent plan at $100/mo per line. Enterprise is custom.

No per-message fees

Flat per-line pricing with unlimited texting under fair use.

Uptime SLA

Not listedSite cites a 99.9% uptime record and a public status page. No contractual SLA found.

99.99% uptime SLA on the Enterprise plan

Isolated infrastructure

PartialEach rep gets a dedicated line that is never shared. Other infrastructure is not described.

A dedicated HIPAA instance for HIPAA customers

SOC 2 Type II

Not listed

SOC 2 Type II, report on request.

GDPR

PartialPrivacy policy lists GDPR and UK GDPR rights. No DPA found.

Checked on each provider's own site and docs on 2026-10-25. “Not listed” means the provider does not mention it.

Project Blue vs Sendblue

Compare Project Blue and Sendblue side by side: iMessage features, channels, developer tools, pricing and compliance, checked on each provider's own site.

Project Blue

Sendblue

Where Project Blue is ahead

Where Sendblue is ahead

Feature comparison

Pricing

Project Blue

Sendblue

Which should you choose?

Frequently asked questions

More Project Blue comparisons

More Sendblue comparisons