What is the difference between Inkbox and MessageBlue?

Inkbox supports 45 of the 77 features compared here, and MessageBlue supports 38. Inkbox adds threaded replies, message effects, contact cards, sender name and photo and shared numbers. MessageBlue adds voice messages, bring your own number, self-hosting, local testing and no-code integrations.

Does MessageBlue support threaded replies?

MessageBlue does not list threaded replies on its site or in its docs.

Does MessageBlue support message effects?

MessageBlue does not list message effects on its site or in its docs.

Does MessageBlue support contact cards?

MessageBlue does not list contact cards on its site or in its docs.

Inkbox vs MessageBlue

Q: How much do Inkbox and MessageBlue cost?

Inkbox: Free covers 3 identities with shared iMessage; Developer is $25 a month with a VoIP number; Startup is $167 a month with one dedicated iMessage number; Enterprise is custom. SMS/MMS and call minutes over allowance cost $0.03 each. MessageBlue: Free when you bring your own number on your own Mac; a dedicated line is $100 a month on Startups & SMB, and Business and Enterprise are contact sales.

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

Inkbox

Email, phone, iMessage and A2A identity for AI agents

Starting price: $25/month (Developer); $167/month for a dedicated iMessage number (Startup)
Free plan: Free: 3 identities, shared iMessage up to 2,000 messages a month and 3 recipients at a time

Visit Inkbox Read more

MessageBlue

iMessage API for agents, with bring-your-own-number

Starting price: $100/month per line
Free plan: $0 with your own number and Mac, all features, limited seats

Visit MessageBlue Read more

Inkbox supports 45 of the 77 features compared here, and MessageBlue supports 38.

Where Inkbox is ahead

and 8 more in the table below.

Where MessageBlue is ahead

and 1 more in the table below.

Feature comparison

Feature	Inkbox	MessageBlue
iMessage messaging
iMessage	SupportedShared router service on every plan, or a dedicated line from the Startup plan.	Supported
Group chats	SupportedDedicated lines only, 2 to 8 remote participants. Shared service is 1:1.	SupportedSend text, attachments and voice notes to groups; receive group messages.
Group management	PartialCreate a group by sending to 2 to 8 numbers. No add or remove member API in V1.	PartialCreate groups of 2 to 31 by API; no add or remove participant endpoints.
Group name and photo	Not listed	Not listed
Mentions	Not listed	Not listed
Tapbacks	SupportedSend, replace and remove 7 tapbacks including eyes; inbound tapbacks arrive by webhook.	SupportedSend or remove emoji or tapbacks; inbound tapbacks arrive by webhook.
Threaded replies	Supportedreply_to_message_id in 1:1 and group chats, with thread reads. Falls back to a plain reply.	Not listed
Typing indicators	PartialSend only, in 1:1 chats. Groups and inbound typing events are not supported.	SupportedSend and stop, up to 20 seconds; no inbound typing webhook documented.
Read receipts	PartialSend read receipts in 1:1 chats. No read status for your own sent messages is documented.	SupportedSend read receipts; outbound messages report a read status.
Edit and unsend	Not listed	Not listed
Message effects	Supported4 bubble and 9 full-screen send styles, in 1:1 and dedicated-line groups.	Not listed
Animated text effects	Not listed	Not listed
Stickers	Not listed	Not listed
Formatted text	Not listed	Not listed
Attachments	SupportedOne media item per message, uploads up to 10 MiB. No media before the recipient's first reply.	SupportedAttachments by public URL.
Live Photos	Not listed	Not listed
Rich link previews	Not listed	Not listed
Voice messages	Not listed	SupportedTo individuals and groups.
Contact cards	PartialThe router sends the agent's contact card on connect. Sending other vCards is not documented.	Not listed
Polls	Not listed	Not listed
Chat backgrounds	Not listed	Not listed
Location sharing	Not listed	Not listed
iMessage apps	Not listed	Not listed
Live app cards	Not listed	Not listed
Sender name and photo	SupportedDedicated lines share the identity's display name and avatar automatically.	Not listed
FaceTime calls	Not listedCalls run over iMessage lines, but the docs do not say whether they are FaceTime.	Not listedInbox video call button is marked coming soon; voice calls need the team to enable.
Delivery status	Supportedimessage.sent, imessage.delivered and imessage.delivery_failed webhooks, per recipient in groups.	Supportedsent, delivered, read, SMS_FALLBACK and failed via status webhook.
iMessage availability check	SupportedReturns iMessage, SMS or RCS for any E.164 number.	SupportedCheck a number, or a whole group's participants, before sending.
Focus and Notify Anyway	Not listed	Not listed
Numbers and delivery
Managed lines	SupportedShared router lines and dedicated lines run by Inkbox. No Mac needed.	SupportedRequest a number and the team provisions it, typically in 3 to 5 business days.
Dedicated numbers	SupportedStartup plan includes one dedicated iMessage number. VoIP numbers for calls and SMS from Developer.	Supported$100/mo per line on Startups & SMB.
Shared numbers	SupportedFree and paid plans include shared iMessage. The human must text the router first.	Not listed
Bring your own number	Not listed	SupportedPair your own Mac and its Apple ID number with the MessageBlue agent.
Line pooling	BetaOrganization-owned shared iMessage pools, beta and by request only.	SupportedAssigns the least-mapped number per contact and remaps contacts if a number is blocked.
SMS fallback	SupportedInkbox tries iMessage first and can fall back to SMS; was_downgraded marks it.	SupportedStatus event reports SMS_FALLBACK; not available for group creation.
RCS fallback	PartialDocs describe SMS fallback, and the service field can report rcs. The transport cannot be chosen.	Not listedMarketing pages say SMS or RCS fallback; docs only describe SMS.
Outbound-first messaging	PartialDedicated lines can start chats, up to 40 new recipients a day. Shared service needs the human to text first.	SupportedStart chats with any iMessage-capable number; warns after 5 unanswered messages.
Calls on the iMessage number	SupportedAgents place and receive voice calls over shared and dedicated iMessage lines.	Not listedInbox voice call button says to contact the team; number used is not stated.
Other channels
SMS	SupportedSMS and MMS on dedicated VoIP numbers, US and Canada included. Group MMS is beta.	PartialOnly as fallback; new chats need an iMessage-capable recipient.
RCS	PartialOnly as a transport reported on iMessage lines; not a channel you can pick.	Not listedMentioned only as a fallback on marketing pages.
WhatsApp	Not supportedNot offered	Not supportedNot offered
Telegram	Not supported	Not supported
Slack	BetaSlack is in beta: read, reply, files and retained history search.	Not supported
Email	SupportedEach identity gets a mailbox, with custom domains and IMAP/SMTP access.	Not supported
Phone calls	SupportedInbound and outbound calls with your own WebSocket agent or Inkbox Voice AI (beta).	Not listedInbox voice call button says to contact the team; call type and number not stated.
Apple Messages for Business	Not supportedNot offered	Not supportedNot offered
Unified channel API	PartialOne identity and one webhook subscription across channels, but separate APIs per channel.	PartialOne API for iMessage and its SMS fallback only.
Developer tools
REST API	Supported	SupportedOpenAPI 3.1 spec published.
TypeScript SDK	Supported@inkbox/sdk	Supportednpm messageblue (0.0.7), generated from the OpenAPI spec.
Python SDK	Supportedinkbox on PyPI	Not supportedDocs say only TypeScript is published today; other languages on request.
Other SDKs	SupportedRust SDK (inkbox crate).	Not supported
CLI	Supported@inkbox/cli	Not listedThe API page mentions a CLI, but none is documented.
Webhooks	Supported	SupportedInbound and status URLs with retries and dead-lettering.
Signed webhooks	SupportedHMAC-SHA256 with a per-identity signing key.	SupportedX-MB-Signature: HMAC-SHA256 over timestamp and raw body.
MCP server	SupportedRemote Streamable HTTP endpoint at inkbox.ai/mcp, with a separate ChatGPT endpoint.	PartialDocumentation-only MCP server at docs.messageblue.ai/_mcp/server.
Open source	PartialSDK, CLI, skills and examples are MIT on GitHub. The service is closed.	Not listed
Self-hosting	Not listed	SupportedEnterprise plan: your cloud (BYOC), VPC or on-prem
Local testing	Not listed	PartialBrowser test bench runs the no-code agent without sending an iMessage.
Custom channel providers	Not listed	Not listed
Event replay	SupportedDelivery log with replay. Incoming-call and Slack deliveries cannot be replayed.	SupportedFailed and dead-lettered deliveries are kept and can be replayed.
OpenTelemetry	Not listed	Not listed
No-code integrations	Not listed	SupportedZapier, plus a no-code agent builder.
CRM integrations	Not listed	SupportedAgent connects to Salesforce, HubSpot and others; HubSpot inbox sync is private beta.
Built for AI agents
Agent framework	PartialIdentity layer with contact memories across email, texts and calls. No conversation framework.	SupportedNo-code agent with model choice, prompt, knowledge, tools, memory and multi-step tasks.
Agent framework integrations	SupportedPlugins for Hermes Agent, OpenClaw, OpenCode, Codex, Claude Code and DeepSeek Harness.	Not listedSite says it works with LangChain and the Vercel AI SDK via webhooks; no official integration.
Streaming replies	Not listed	Not listed
Agent group chats	Not listedAgents can reach each other over A2A tasks, but not in group chats.	Not listed
Human handoff	PartialPeople can reply from the Console, and Voice AI can transfer a call. No handoff controls for agents.	SupportedTeam inbox for manual replies; pause the agent or block it per contact.
Audit logs	Not listed	SupportedOn the Business and Enterprise plans
Message history API	SupportedList and read conversations and threads, with search on texts and email.	SupportedConversation by phone number.
Plans and compliance
Free plan	SupportedFree: 3 identities, shared iMessage up to 2,000 messages a month and 3 recipients at a time.	Supported$0 when you bring your own number on your own Mac; every feature included.
Public pricing	Supported	SupportedFree and $100/mo listed; Business and Enterprise are contact sales.
No per-message fees	PartialiMessage is capped per plan with no per-message fee. Extra SMS/MMS and call minutes cost $0.03 each.	SupportedFlat $100/mo per line.
Uptime SLA	Not listed	Supported99.9% SLA listed from the $100 plan; the API page says enterprise plans
Isolated infrastructure	PartialDedicated iMessage infrastructure is listed for Enterprise only.	SupportedEnterprise plan: single-tenant or self-hosted stack
SOC 2 Type II	Not listed	PartialEnterprise page claims audited SOC 2 Type II; pricing says SOC 2 ready; no report found.
GDPR	Not listedThe DPA names the CCPA only; GDPR is not mentioned.	Not listed

Feature

Inkbox

MessageBlue

iMessage messaging

iMessage

Shared router service on every plan, or a dedicated line from the Startup plan.

Group chats

Dedicated lines only, 2 to 8 remote participants. Shared service is 1:1.

Send text, attachments and voice notes to groups; receive group messages.

Group management

PartialCreate a group by sending to 2 to 8 numbers. No add or remove member API in V1.

PartialCreate groups of 2 to 31 by API; no add or remove participant endpoints.

Group name and photo

Not listed

Mentions

Not listed

Tapbacks

Send, replace and remove 7 tapbacks including eyes; inbound tapbacks arrive by webhook.

Send or remove emoji or tapbacks; inbound tapbacks arrive by webhook.

Threaded replies

reply_to_message_id in 1:1 and group chats, with thread reads. Falls back to a plain reply.

Not listed

Typing indicators

PartialSend only, in 1:1 chats. Groups and inbound typing events are not supported.

Send and stop, up to 20 seconds; no inbound typing webhook documented.

Read receipts

PartialSend read receipts in 1:1 chats. No read status for your own sent messages is documented.

Send read receipts; outbound messages report a read status.

Edit and unsend

Not listed

Message effects

4 bubble and 9 full-screen send styles, in 1:1 and dedicated-line groups.

Not listed

Animated text effects

Not listed

Stickers

Not listed

Formatted text

Not listed

Attachments

One media item per message, uploads up to 10 MiB. No media before the recipient's first reply.

Attachments by public URL.

Live Photos

Not listed

Rich link previews

Not listed

Voice messages

Not listed

To individuals and groups.

Contact cards

PartialThe router sends the agent's contact card on connect. Sending other vCards is not documented.

Not listed

Not listed

Not listed

Not listed

Not listed

Not listed

Sender name and photo

Dedicated lines share the identity's display name and avatar automatically.

Not listed

FaceTime calls

Not listedCalls run over iMessage lines, but the docs do not say whether they are FaceTime.

Not listedInbox video call button is marked coming soon; voice calls need the team to enable.

Delivery status

imessage.sent, imessage.delivered and imessage.delivery_failed webhooks, per recipient in groups.

sent, delivered, read, SMS_FALLBACK and failed via status webhook.

iMessage availability check

Returns iMessage, SMS or RCS for any E.164 number.

Check a number, or a whole group's participants, before sending.

Focus and Notify Anyway

Not listed

Numbers and delivery

Managed lines

Shared router lines and dedicated lines run by Inkbox. No Mac needed.

Request a number and the team provisions it, typically in 3 to 5 business days.

Dedicated numbers

Startup plan includes one dedicated iMessage number. VoIP numbers for calls and SMS from Developer.

$100/mo per line on Startups & SMB.

Shared numbers

Free and paid plans include shared iMessage. The human must text the router first.

Not listed

Bring your own number

Not listed

Pair your own Mac and its Apple ID number with the MessageBlue agent.

Line pooling

BetaOrganization-owned shared iMessage pools, beta and by request only.

Assigns the least-mapped number per contact and remaps contacts if a number is blocked.

SMS fallback

Inkbox tries iMessage first and can fall back to SMS; was_downgraded marks it.

Status event reports SMS_FALLBACK; not available for group creation.

RCS fallback

PartialDocs describe SMS fallback, and the service field can report rcs. The transport cannot be chosen.

Not listedMarketing pages say SMS or RCS fallback; docs only describe SMS.

Outbound-first messaging

PartialDedicated lines can start chats, up to 40 new recipients a day. Shared service needs the human to text first.

Start chats with any iMessage-capable number; warns after 5 unanswered messages.

Calls on the iMessage number

Agents place and receive voice calls over shared and dedicated iMessage lines.

Not listedInbox voice call button says to contact the team; number used is not stated.

Other channels

SMS

SMS and MMS on dedicated VoIP numbers, US and Canada included. Group MMS is beta.

PartialOnly as fallback; new chats need an iMessage-capable recipient.

RCS

PartialOnly as a transport reported on iMessage lines; not a channel you can pick.

Not listedMentioned only as a fallback on marketing pages.

Not supportedNot offered

Not supported

Slack

BetaSlack is in beta: read, reply, files and retained history search.

Not supported

Each identity gets a mailbox, with custom domains and IMAP/SMTP access.

Not supported

Phone calls

Inbound and outbound calls with your own WebSocket agent or Inkbox Voice AI (beta).

Not listedInbox voice call button says to contact the team; call type and number not stated.

Apple Messages for Business

Not supportedNot offered

Unified channel API

PartialOne identity and one webhook subscription across channels, but separate APIs per channel.

PartialOne API for iMessage and its SMS fallback only.

Developer tools

REST API

OpenAPI 3.1 spec published.

TypeScript SDK

@inkbox/sdk

npm messageblue (0.0.7), generated from the OpenAPI spec.

Python SDK

inkbox on PyPI

Not supportedDocs say only TypeScript is published today; other languages on request.

Other SDKs

Rust SDK (inkbox crate).

Not supported

CLI

@inkbox/cli

Not listedThe API page mentions a CLI, but none is documented.

Webhooks

Inbound and status URLs with retries and dead-lettering.

Signed webhooks

HMAC-SHA256 with a per-identity signing key.

X-MB-Signature: HMAC-SHA256 over timestamp and raw body.

MCP server

Remote Streamable HTTP endpoint at inkbox.ai/mcp, with a separate ChatGPT endpoint.

PartialDocumentation-only MCP server at docs.messageblue.ai/_mcp/server.

Open source

PartialSDK, CLI, skills and examples are MIT on GitHub. The service is closed.

Not listed

Self-hosting

Not listed

Enterprise plan: your cloud (BYOC), VPC or on-prem

Local testing

Not listed

PartialBrowser test bench runs the no-code agent without sending an iMessage.

Custom channel providers

Not listed

Event replay

Delivery log with replay. Incoming-call and Slack deliveries cannot be replayed.

Failed and dead-lettered deliveries are kept and can be replayed.

OpenTelemetry

Not listed

No-code integrations

Not listed

Zapier, plus a no-code agent builder.

CRM integrations

Not listed

Agent connects to Salesforce, HubSpot and others; HubSpot inbox sync is private beta.

Built for AI agents

Agent framework

PartialIdentity layer with contact memories across email, texts and calls. No conversation framework.

No-code agent with model choice, prompt, knowledge, tools, memory and multi-step tasks.

Agent framework integrations

Plugins for Hermes Agent, OpenClaw, OpenCode, Codex, Claude Code and DeepSeek Harness.

Not listedSite says it works with LangChain and the Vercel AI SDK via webhooks; no official integration.

Streaming replies

Not listed

Agent group chats

Not listedAgents can reach each other over A2A tasks, but not in group chats.

Not listed

Human handoff

PartialPeople can reply from the Console, and Voice AI can transfer a call. No handoff controls for agents.

Team inbox for manual replies; pause the agent or block it per contact.

Audit logs

Not listed

On the Business and Enterprise plans

Message history API

List and read conversations and threads, with search on texts and email.

Conversation by phone number.

Plans and compliance

Free plan

Free: 3 identities, shared iMessage up to 2,000 messages a month and 3 recipients at a time.

$0 when you bring your own number on your own Mac; every feature included.

Public pricing

Free and $100/mo listed; Business and Enterprise are contact sales.

No per-message fees

PartialiMessage is capped per plan with no per-message fee. Extra SMS/MMS and call minutes cost $0.03 each.

Flat $100/mo per line.

Uptime SLA

Not listed

99.9% SLA listed from the $100 plan; the API page says enterprise plans

Isolated infrastructure

PartialDedicated iMessage infrastructure is listed for Enterprise only.

Enterprise plan: single-tenant or self-hosted stack

SOC 2 Type II

Not listed

PartialEnterprise page claims audited SOC 2 Type II; pricing says SOC 2 ready; no report found.

GDPR

Not listedThe DPA names the CCPA only; GDPR is not mentioned.

Not listed

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

Pricing

Inkbox

Free covers 3 identities with shared iMessage; Developer is $25 a month with a VoIP number; Startup is $167 a month with one dedicated iMessage number; Enterprise is custom. SMS/MMS and call minutes over allowance cost $0.03 each.

Pricing model: monthly plans with allowances, plus per-unit SMS/MMS and call-minute overage

Source

MessageBlue

Free when you bring your own number on your own Mac; a dedicated line is $100 a month on Startups & SMB, and Business and Enterprise are contact sales.

Pricing model: flat per line

Source