What is the difference between Comms by Osis and Inkbox?

Comms by Osis supports 43 of the 77 features compared here, and Inkbox supports 45. Comms by Osis adds group name and photo, edit and unsend, polls, chat backgrounds and location sharing. Inkbox adds message effects, line pooling, Slack, email and TypeScript SDK.

How much do Comms by Osis and Inkbox cost?

Comms by Osis: Free on a shared line with 100 messages a day, Plus at $50 a month on a shared line, Dedicated at $200 a month per number with $0 setup, and custom Enterprise; AI usage is billed separately. 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.

Does Inkbox support group name and photo?

Inkbox does not list group name and photo on its site or in its docs.

Does Inkbox support edit and unsend?

Inkbox does not list edit and unsend on its site or in its docs.

Does Inkbox support polls?

Inkbox does not list polls on its site or in its docs.

Comms by Osis vs Inkbox

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

Comms by Osis

iMessage, RCS, SMS and WhatsApp API with hosted agents

Starting price: $50/month (shared line); $200/month per dedicated number
Free plan: Free: shared platform line, 100 messages a day, no card

Visit Comms by Osis Read more

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

Comms by Osis supports 43 of the 77 features compared here, and Inkbox supports 45.

Where Comms by Osis is ahead

and 1 more in the table below.

Where Inkbox is ahead

and 3 more in the table below.

Feature comparison

Feature	Comms by Osis	Inkbox
iMessage messaging
iMessage	Supported	SupportedShared router service on every plan, or a dedicated line from the Startup plan.
Group chats	SupportedGroups of 2 to 31 people from a dedicated line with group support. Not on the shared line.	SupportedDedicated lines only, 2 to 8 remote participants. Shared service is 1:1.
Group management	PartialCreate a group with its first message; adding or removing members is not documented.	PartialCreate a group by sending to 2 to 8 numbers. No add or remove member API in V1.
Group name and photo	PartialName a group when you create it; group photos and renames are not documented.	Not listed
Mentions	Not listed	Not listed
Tapbacks	SupportedClassic tapbacks or custom emoji, add, replace or remove; reaction webhooks for inbound.	SupportedSend, replace and remove 7 tapbacks including eyes; inbound tapbacks arrive by webhook.
Threaded replies	Supportedreply_to_message_id replies inside an iMessage thread; text only.	Supportedreply_to_message_id in 1:1 and group chats, with thread reads. Falls back to a plain reply.
Typing indicators	SupportedShow or hide typing dots on iMessage, RCS and WhatsApp.	PartialSend only, in 1:1 chats. Groups and inbound typing events are not supported.
Read receipts	SupportedMark a conversation read to send a receipt; comms.message.read for one-to-one chats.	PartialSend read receipts in 1:1 chats. No read status for your own sent messages is documented.
Edit and unsend	PartialUnsend within Apple's 2-minute window on supported lines. No edit endpoint; inbound edits fire events.	Not listed
Message effects	Not listed	Supported4 bubble and 9 full-screen send styles, in 1:1 and dedicated-line groups.
Animated text effects	Not listed	Not listed
Stickers	Not listed	Not listed
Formatted text	Not listed	Not listed
Attachments	SupportedUp to 32 files and 9 MiB per message, sent as base64.	SupportedOne media item per message, uploads up to 10 MiB. No media before the recipient's first reply.
Live Photos	Not listed	Not listed
Rich link previews	Not listed	Not listed
Voice messages	Not listedVoice notes are documented for WhatsApp only.	Not listed
Contact cards	SupportedSend a vCard over iMessage, SMS or WhatsApp.	PartialThe router sends the agent's contact card on connect. Sending other vCards is not documented.
Polls	Supported2 to 12 options; votes arrive as comms.poll.voted. Tap to vote on iOS 26 and later.	Not listed
Chat backgrounds	BetaExperimental: photo or gradient backgrounds on lines that support them.	Not listed
Location sharing	PartialRead locations that contacts choose to share, with update webhooks; the API cannot request a share.	Not listed
iMessage apps	Not listed	Not listed
Live app cards	Not listed	Not listed
Sender name and photo	SupportedContact card API sets name and photo, with native name and photo sharing on supported lines.	SupportedDedicated lines share the identity's display name and avatar automatically.
FaceTime calls	PartialAnswer inbound FaceTime audio and video calls by API and stream audio; outbound calls not documented.	Not listedCalls run over iMessage lines, but the docs do not say whether they are FaceTime.
Delivery status	Supportedsent, delivered and read events, plus a list of delivery attempts.	Supportedimessage.sent, imessage.delivered and imessage.delivery_failed webhooks, per recipient in groups.
iMessage availability check	SupportedChecks iMessage, RCS and WhatsApp for a phone number, or iMessage for an email.	SupportedReturns iMessage, SMS or RCS for any E.164 number.
Focus and Notify Anyway	Not listed	Not listed
Numbers and delivery
Managed lines	SupportedHosted lines; no Mac to run.	SupportedShared router lines and dedicated lines run by Inkbox. No Mac needed.
Dedicated numbers	SupportedDedicated plan: $200 a month per number.	SupportedStartup plan includes one dedicated iMessage number. VoIP numbers for calls and SMS from Developer.
Shared numbers	SupportedFree and Plus plans run on a shared platform line.	SupportedFree and paid plans include shared iMessage. The human must text the router first.
Bring your own number	SupportedPort an existing number to a dedicated line; needs approval and a supported number.	Not listed
Line pooling	Not listed	BetaOrganization-owned shared iMessage pools, beta and by request only.
SMS fallback	SupportedAuto routing falls back to SMS only after a clear rejection.	SupportedInkbox tries iMessage first and can fall back to SMS; was_downgraded marks it.
RCS fallback	PartialAuto routing tries RCS for plain text on supported dedicated lines with carrier enablement.	PartialDocs describe SMS fallback, and the service field can report rcs. The transport cannot be chosen.
Outbound-first messaging	SupportedDedicated lines can start conversations.	PartialDedicated lines can start chats, up to 40 new recipients a day. Shared service needs the human to text first.
Calls on the iMessage number	PartialInbound phone and FaceTime calls to the line can be answered by API; outbound is not documented.	SupportedAgents place and receive voice calls over shared and dedicated iMessage lines.
Other channels
SMS	SupportedChoose sms explicitly or let auto routing fall back to it.	SupportedSMS and MMS on dedicated VoIP numbers, US and Canada included. Group MMS is beta.
RCS	PartialOne plain-text message to one number, on supported dedicated lines with carrier enablement.	PartialOnly as a transport reported on iMessage lines; not a channel you can pick.
WhatsApp	SupportedSends from the number's WhatsApp Business account when WhatsApp is turned on for it.	Not supportedNot offered
Telegram	Not supportedNot offered	Not supported
Slack	Not supported	BetaSlack is in beta: read, reply, files and retained history search.
Email	Not supportedNot offered as a channel; the capability check accepts Apple ID emails for iMessage.	SupportedEach identity gets a mailbox, with custom domains and IMAP/SMTP access.
Phone calls	PartialInbound cellular calls can be answered by API, but audio relay works only for FaceTime for now.	SupportedInbound and outbound calls with your own WebSocket agent or Inkbox Voice AI (beta).
Apple Messages for Business	Not supportedNot offered; the site says Comms is distinct from Apple Messages for Business.	Not supportedNot offered
Unified channel API	SupportedOne send endpoint and message model for iMessage, RCS, WhatsApp and SMS.	PartialOne identity and one webhook subscription across channels, but separate APIs per channel.
Developer tools
REST API	Supported	Supported
TypeScript SDK	Not listedOnly a runnable Node.js example is published.	Supported@inkbox/sdk
Python SDK	Not listed	Supportedinkbox on PyPI
Other SDKs	Not listed	SupportedRust SDK (inkbox crate).
CLI	Not listed	Supported@inkbox/cli
Webhooks	Supported	Supported
Signed webhooks	SupportedHMAC-SHA256 in X-Osis-Signature.	SupportedHMAC-SHA256 with a per-identity signing key.
MCP server	SupportedHosted MCP server with OAuth or a scoped API key.	SupportedRemote Streamable HTTP endpoint at inkbox.ai/mcp, with a separate ChatGPT endpoint.
Open source	Not listed	PartialSDK, CLI, skills and examples are MIT on GitHub. The service is closed.
Self-hosting	Not listed	Not listed
Local testing	Not listed	Not listed
Custom channel providers	Not listed	Not listed
Event replay	PartialUp to six delivery retries and a delivery attempts list; no replay endpoint is documented.	SupportedDelivery log with replay. Incoming-call and Slack deliveries cannot be replayed.
OpenTelemetry	Not listed	Not listed
No-code integrations	BetaHighLevel connector is a development preview; Marketplace approval is pending.	Not listed
CRM integrations	Not listed	Not listed
Built for AI agents
Agent framework	SupportedHosted agents with instructions, knowledge, handoff and MCP tool connections.	PartialIdentity layer with contact memories across email, texts and calls. No conversation framework.
Agent framework integrations	Not listed	SupportedPlugins for Hermes Agent, OpenClaw, OpenCode, Codex, Claude Code and DeepSeek Harness.
Streaming replies	Not listed	Not listed
Agent group chats	Not listed	Not listedAgents can reach each other over A2A tasks, but not in group chats.
Human handoff	SupportedHandoff controls pause the hosted agent while a person replies in the team inbox.	PartialPeople can reply from the Console, and Voice AI can transfer a call. No handoff controls for agents.
Audit logs	Not listed	Not listed
Message history API	SupportedList messages and conversations on your lines.	SupportedList and read conversations and threads, with search on texts and email.
Plans and compliance
Free plan	SupportedFree: shared platform line, 100 messages a day, no card.	SupportedFree: 3 identities, shared iMessage up to 2,000 messages a month and 3 recipients at a time.
Public pricing	Supported	Supported
No per-message fees	SupportedFlat plans; AI usage and answered call minutes are billed separately.	PartialiMessage is capped per plan with no per-message fee. Extra SMS/MMS and call minutes cost $0.03 each.
Uptime SLA	Not listed	Not listed
Isolated infrastructure	Not listed	PartialDedicated iMessage infrastructure is listed for Enterprise only.
SOC 2 Type II	Not listed	Not listed
GDPR	Not listedThe privacy policy mentions GDPR rights; no DPA was found.	Not listedThe DPA names the CCPA only; GDPR is not mentioned.

Feature

Comms by Osis

Inkbox

iMessage messaging

iMessage

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

Group chats

Groups of 2 to 31 people from a dedicated line with group support. Not on the shared line.

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

Group management

PartialCreate a group with its first message; adding or removing members is not documented.

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

Group name and photo

PartialName a group when you create it; group photos and renames are not documented.

Not listed

Mentions

Not listed

Tapbacks

Classic tapbacks or custom emoji, add, replace or remove; reaction webhooks for inbound.

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

Threaded replies

reply_to_message_id replies inside an iMessage thread; text only.

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

Typing indicators

Show or hide typing dots on iMessage, RCS and WhatsApp.

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

Read receipts

Mark a conversation read to send a receipt; comms.message.read for one-to-one chats.

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

Edit and unsend

PartialUnsend within Apple's 2-minute window on supported lines. No edit endpoint; inbound edits fire events.

Not listed

Message effects

Not listed

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

Animated text effects

Not listed

Stickers

Not listed

Formatted text

Not listed

Attachments

Up to 32 files and 9 MiB per message, sent as base64.

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

Live Photos

Not listed

Rich link previews

Not listed

Voice messages

Not listedVoice notes are documented for WhatsApp only.

Not listed

Contact cards

Send a vCard over iMessage, SMS or WhatsApp.

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

Polls

2 to 12 options; votes arrive as comms.poll.voted. Tap to vote on iOS 26 and later.

Not listed

Chat backgrounds

BetaExperimental: photo or gradient backgrounds on lines that support them.

Not listed

Location sharing

PartialRead locations that contacts choose to share, with update webhooks; the API cannot request a share.

Not listed

iMessage apps

Not listed

Live app cards

Not listed

Sender name and photo

Contact card API sets name and photo, with native name and photo sharing on supported lines.

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

FaceTime calls

PartialAnswer inbound FaceTime audio and video calls by API and stream audio; outbound calls not documented.

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

Delivery status

sent, delivered and read events, plus a list of delivery attempts.

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

iMessage availability check

Checks iMessage, RCS and WhatsApp for a phone number, or iMessage for an email.

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

Focus and Notify Anyway

Not listed

Numbers and delivery

Managed lines

Hosted lines; no Mac to run.

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

Dedicated numbers

Dedicated plan: $200 a month per number.

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

Shared numbers

Free and Plus plans run on a shared platform line.

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

Bring your own number

Port an existing number to a dedicated line; needs approval and a supported number.

Not listed

Line pooling

Not listed

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

SMS fallback

Auto routing falls back to SMS only after a clear rejection.

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

RCS fallback

PartialAuto routing tries RCS for plain text on supported dedicated lines with carrier enablement.

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

Outbound-first messaging

Dedicated lines can start conversations.

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

Calls on the iMessage number

PartialInbound phone and FaceTime calls to the line can be answered by API; outbound is not documented.

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

Other channels

SMS

Choose sms explicitly or let auto routing fall back to it.

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

RCS

PartialOne plain-text message to one number, on supported dedicated lines with carrier enablement.

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

Sends from the number's WhatsApp Business account when WhatsApp is turned on for it.

Not supportedNot offered

Not supported

Slack

Not supported

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

Not supportedNot offered as a channel; the capability check accepts Apple ID emails for iMessage.

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

Phone calls

PartialInbound cellular calls can be answered by API, but audio relay works only for FaceTime for now.

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

Apple Messages for Business

Not supportedNot offered; the site says Comms is distinct from Apple Messages for Business.

Not supportedNot offered

Unified channel API

One send endpoint and message model for iMessage, RCS, WhatsApp and SMS.

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

Developer tools

REST API

TypeScript SDK

Not listedOnly a runnable Node.js example is published.

@inkbox/sdk

Python SDK

Not listed

inkbox on PyPI

Other SDKs

Not listed

Rust SDK (inkbox crate).

CLI

Not listed

@inkbox/cli

Webhooks

Signed webhooks

HMAC-SHA256 in X-Osis-Signature.

HMAC-SHA256 with a per-identity signing key.

MCP server

Hosted MCP server with OAuth or a scoped API key.

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

Open source

Not listed

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

Self-hosting

Not listed

Local testing

Not listed

Custom channel providers

Not listed

Event replay

PartialUp to six delivery retries and a delivery attempts list; no replay endpoint is documented.

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

OpenTelemetry

Not listed

No-code integrations

BetaHighLevel connector is a development preview; Marketplace approval is pending.

Not listed

CRM integrations

Not listed

Built for AI agents

Agent framework

Hosted agents with instructions, knowledge, handoff and MCP tool connections.

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

Agent framework integrations

Not listed

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

Streaming replies

Not listed

Agent group chats

Not listed

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

Human handoff

Handoff controls pause the hosted agent while a person replies in the team inbox.

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

Audit logs

Not listed

Message history API

List messages and conversations on your lines.

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

Plans and compliance

Free plan

Free: shared platform line, 100 messages a day, no card.

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

Public pricing

No per-message fees

Flat plans; AI usage and answered call minutes are billed separately.

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

Uptime SLA

Not listed

Isolated infrastructure

Not listed

PartialDedicated iMessage infrastructure is listed for Enterprise only.

SOC 2 Type II

Not listed

GDPR

Not listedThe privacy policy mentions GDPR rights; no DPA was found.

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

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

Pricing

Comms by Osis

Free on a shared line with 100 messages a day, Plus at $50 a month on a shared line, Dedicated at $200 a month per number with $0 setup, and custom Enterprise; AI usage is billed separately.

Pricing model: flat monthly per plan or dedicated line; AI usage and call minutes extra

Source

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