What is the difference between Inkbox and Project Blue?

Inkbox supports 45 of the 77 features compared here, and Project Blue supports 42. Inkbox adds threaded replies, read receipts, RCS fallback, email and Python SDK. Project Blue adds group name and photo, voice messages, FaceTime calls, bring your own number and WhatsApp.

Does Project Blue support threaded replies?

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

Does Project Blue support read receipts?

Project Blue does not list read receipts on its site or in its docs.

Does Project Blue support RCS fallback?

Project Blue does not list RCS fallback on its site or in its docs.

Inkbox vs Project Blue

Q: How much do Inkbox and Project Blue 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. 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.

Compare Inkbox and Project Blue 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

Project Blue

iMessage, SMS and FaceTime Audio lines inside your CRM

Starting price: $166/month per line, billed annually
Free plan: Free trial on a shared line, verified numbers only

Visit Project Blue Read more

Inkbox supports 45 of the 77 features compared here, and Project Blue supports 42.

Where Inkbox is ahead

and 3 more in the table below.

Where Project Blue is ahead

Feature comparison

Feature	Inkbox	Project Blue
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 to groups of 2 to 32 by API. Not on trial accounts, and group sends do not sync to the CRM.
Group management	PartialCreate a group by sending to 2 to 8 numbers. No add or remove member API in V1.	PartialGroups are created by sending to a set of numbers. No add or remove member endpoints documented.
Group name and photo	Not listed	PartialgroupName can be set when a group is created. No group photo documented.
Mentions	Not listed	Not listed
Tapbacks	SupportedSend, replace and remove 7 tapbacks including eyes; inbound tapbacks arrive by webhook.	PartialSend or remove the six classic tapbacks on inbound iMessages. Receiving reactions is not documented.
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.	PartialSend only, iMessage only, into an existing conversation. Inbound typing events not documented.
Read receipts	PartialSend read receipts in 1:1 chats. No read status for your own sent messages is documented.	Not listed
Edit and unsend	Not listed	Not listed
Message effects	Supported4 bubble and 9 full-screen send styles, in 1:1 and dedicated-line groups.	Supported4 bubble and 9 screen effects through the effect field. iMessage only.
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.	SupportedImages, videos and vCards by URL.
Live Photos	Not listed	Not listed
Rich link previews	Not listed	Not listed
Voice messages	Not listed	SupportedAudio files sent as voice memos, plus AI text-to-speech voice memos.
Contact cards	PartialThe router sends the agent's contact card on connect. Sending other vCards is not documented.	SupportedVCF files through mediaAttachmentUrl.
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.	SupportedSet, read and share a line's Share Name and Photo card by API.
FaceTime calls	Not listedCalls run over iMessage lines, but the docs do not say whether they are FaceTime.	PartialFaceTime Audio only, outbound and inbound, on FaceTime-enabled accounts. Not on trials.
Delivery status	Supportedimessage.sent, imessage.delivered and imessage.delivery_failed webhooks, per recipient in groups.	PartialMessages carry a status field such as delivered. Webhooks cover only inbound and outbound messages.
iMessage availability check	SupportedReturns iMessage, SMS or RCS for any E.164 number.	Supported
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.	SupportedNo iPhone, Mac or SIM needed. Lines are set up remotely, usually within one business day.
Dedicated numbers	SupportedStartup plan includes one dedicated iMessage number. VoIP numbers for calls and SMS from Developer.	SupportedA dedicated line per rep, never shared. New lines are requested by API and provisioned by the team.
Shared numbers	SupportedFree and paid plans include shared iMessage. The human must text the router first.	PartialTrial accounts only: a shared line that can reach verified numbers.
Bring your own number	Not listed	SupportedExisting numbers can be ported to Project Blue's carrier partner.
Line pooling	BetaOrganization-owned shared iMessage pools, beta and by request only.	SupportedSends without lineId are load balanced across your lines.
SMS fallback	SupportedInkbox tries iMessage first and can fall back to SMS; was_downgraded marks it.	SupportedFalls back to SMS from the same line when iMessage is unavailable.
RCS fallback	PartialDocs describe SMS fallback, and the service field can report rcs. The transport cannot be chosen.	Not listedHomepage describes fallback from iMessage to WhatsApp to SMS. RCS fallback is not described.
Outbound-first messaging	PartialDedicated lines can start chats, up to 40 new recipients a day. Shared service needs the human to text first.	SupportedLines are sold as outbound-ready. Guidelines rule out mass outbound iMessage.
Calls on the iMessage number	SupportedAgents place and receive voice calls over shared and dedicated iMessage lines.	SupportedDialer and FaceTime Audio calls from the same number as the messaging line.
Other channels
SMS	SupportedSMS and MMS on dedicated VoIP numbers, US and Canada included. Group MMS is beta.	Supported
RCS	PartialOnly as a transport reported on iMessage lines; not a channel you can pick.	PartialRCS for rich media was rolled out in 2026. The API lists RCS as inbound only.
WhatsApp	Not supportedNot offered	PartialHomepage lists WhatsApp as a fallback step. No WhatsApp option in the API, and llms.txt says it is not a WhatsApp API.
Telegram	Not supported	Not supportedNot offered
Slack	BetaSlack is in beta: read, reply, files and retained history search.	PartialSlack notifications for inbound replies. Not a messaging channel.
Email	SupportedEach identity gets a mailbox, with custom domains and IMAP/SMTP access.	Not supportedDeveloper page says it is not a general email API.
Phone calls	SupportedInbound and outbound calls with your own WebSocket agent or Inkbox Voice AI (beta).	SupportedCloud dialer with inbound, outbound, routing, recording and voicemail, plus a browser calling SDK.
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 send endpoint covers iMessage and SMS. Calls and FaceTime use separate endpoints.
Developer tools
REST API	Supported	SupportedREST API with Bearer keys and an OpenAPI spec.
TypeScript SDK	Supported@inkbox/sdk	Partial@tryprojectblue/dialer is a browser SDK for phone calls only. No messaging SDK.
Python SDK	Supportedinkbox on PyPI	Not listed
Other SDKs	SupportedRust SDK (inkbox crate).	Not listed
CLI	Supported@inkbox/cli	Not listed
Webhooks	Supported	SupportedInbound and outbound message events and inbound FaceTime call events.
Signed webhooks	SupportedHMAC-SHA256 with a per-identity signing key.	Not listedWebhook docs do not mention signatures.
MCP server	SupportedRemote Streamable HTTP endpoint at inkbox.ai/mcp, with a separate ChatGPT endpoint.	SupportedRemote MCP server with OAuth 2.1, plus an optional Claude Code plugin.
Open source	PartialSDK, CLI, skills and examples are MIT on GitHub. The service is closed.	PartialThe dialer SDK is MIT licensed on npm. The platform is closed.
Self-hosting	Not listed	Not listedHosted service on Project Blue lines. Self-hosting is not mentioned.
Local testing	Not listed	Not listedTrial accounts send real messages to verified numbers; docs say they are not a simulator.
Custom channel providers	Not listed	Not listed
Event replay	SupportedDelivery log with replay. Incoming-call and Slack deliveries cannot be replayed.	Not supportedDocs say webhooks have no retries and failed deliveries are not replayed.
OpenTelemetry	Not listed	Not listed
No-code integrations	Not listed	SupportedGoHighLevel conversation provider with workflow actions and triggers. llms.txt also lists Zapier.
CRM integrations	Not listed	SupportedHubSpot and Close CRM. Salesforce is not listed.
Built for AI agents
Agent framework	PartialIdentity layer with contact memories across email, texts and calls. No conversation framework.	Not listed
Agent framework integrations	SupportedPlugins for Hermes Agent, OpenClaw, OpenCode, Codex, Claude Code and DeepSeek Harness.	Not listed
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.	PartialReps reply in the CRM inbox and can join group threads. No agent handoff controls documented.
Audit logs	Not listed	Not listed
Message history API	SupportedList and read conversations and threads, with search on texts and email.	SupportedList and get messages, inbound and outbound, with filters.
Plans and compliance
Free plan	SupportedFree: 3 identities, shared iMessage up to 2,000 messages a month and 3 recipients at a time.	PartialFree trial on a shared line to verified numbers. Some endpoints are off on trial.
Public pricing	Supported	Supported$166/month per line billed annually, or $199/month per line on a 12-month plan.
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 per-line pricing with unlimited texting under fair use.
Uptime SLA	Not listed	Not listedSite cites a 99.9% uptime record and a public status page. No contractual SLA found.
Isolated infrastructure	PartialDedicated iMessage infrastructure is listed for Enterprise only.	PartialEach rep gets a dedicated line that is never shared. Other infrastructure is not described.
SOC 2 Type II	Not listed	Not listed
GDPR	Not listedThe DPA names the CCPA only; GDPR is not mentioned.	PartialPrivacy policy lists GDPR and UK GDPR rights. No DPA found.

Feature

Inkbox

Project Blue

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

Group management

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

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

Group name and photo

Not listed

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

Mentions

Not listed

Tapbacks

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

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

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.

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

Read receipts

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

Not listed

Edit and unsend

Not listed

Message effects

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

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

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.

Images, videos and vCards by URL.

Live Photos

Not listed

Rich link previews

Not listed

Voice messages

Not listed

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

Contact cards

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

VCF files through mediaAttachmentUrl.

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.

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

FaceTime calls

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

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

Delivery status

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

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

iMessage availability check

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

Focus and Notify Anyway

Not listed

Numbers and delivery

Managed lines

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

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

Dedicated numbers

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

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

Shared numbers

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

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

Bring your own number

Not listed

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

Line pooling

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

Sends without lineId are load balanced across your lines.

SMS fallback

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

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

RCS fallback

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

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

Outbound-first messaging

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

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

Calls on the iMessage number

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

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

Other channels

SMS

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

RCS

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

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

Not supportedNot offered

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

Not supported

Not supportedNot offered

Slack

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

PartialSlack notifications for inbound replies. Not a messaging channel.

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

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

Phone calls

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

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

Apple Messages for Business

Not supportedNot offered

Unified channel API

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

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

Developer tools

REST API

REST API with Bearer keys and an OpenAPI spec.

TypeScript SDK

@inkbox/sdk

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

Python SDK

inkbox on PyPI

Not listed

Other SDKs

Rust SDK (inkbox crate).

Not listed

CLI

@inkbox/cli

Not listed

Webhooks

Inbound and outbound message events and inbound FaceTime call events.

Signed webhooks

HMAC-SHA256 with a per-identity signing key.

Not listedWebhook docs do not mention signatures.

MCP server

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

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

Open source

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

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

Self-hosting

Not listed

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

Local testing

Not listed

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

Custom channel providers

Not listed

Event replay

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

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

OpenTelemetry

Not listed

No-code integrations

Not listed

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

CRM integrations

Not listed

HubSpot and Close CRM. Salesforce is not listed.

Built for AI agents

Agent framework

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

Not listed

Agent framework integrations

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

Not listed

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.

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

Audit logs

Not listed

Message history API

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

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

Plans and compliance

Free plan

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

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

Public pricing

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

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 per-line pricing with unlimited texting under fair use.

Uptime SLA

Not listed

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

Isolated infrastructure

PartialDedicated iMessage infrastructure is listed for Enterprise only.

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

SOC 2 Type II

Not listed

GDPR

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

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.

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