Photon vs Caspian

Photon supports 75 of the 77 features compared here, and Caspian supports 33.

Feature comparison

Feature	Photon	Caspian
iMessage messaging
iMessage	SupportedManaged cloud lines, or your own Mac with the local provider	PartialSelf-host only, through a BlueBubbles-style relay on your own Mac; not live on the hosted gateway
Group chats	SupportedOn the Business plan (dedicated lines)	PartialPython adapter can send to a group chat GUID; inbound messages are keyed to the sender as DMs
Group management	SupportedCreate groups and add, remove or leave members; Business plan (dedicated lines)	Not listed
Group name and photo	SupportedRename groups and set group photos; Business plan (dedicated lines)	Not listed
Mentions	SupportedSend @mentions in multipart messages and read mention ranges on inbound	Not listed
Tapbacks	SupportedSix native tapbacks plus emoji reactions, send and receive	PartialPython adapter sends reactions through the relay; the TypeScript adapter sends text only
Threaded replies	Supported	PartialPython adapter replies to a message GUID through the relay
Typing indicators	Supported	Not supportediMessage example says no typing, edit, delete, buttons or pins
Read receipts	SupportedMark chats read and receive read events; group receipts are best-effort	Not listed
Edit and unsend	SupportedEdit within 15 minutes and unsend within 2 minutes (Apple limits)	Not supportediMessage example says no edit or delete
Message effects	SupportedAll bubble and screen effects, including invisible ink	Not listed
Animated text effects	SupportedPer-range effects such as bloom, shake, explode and jitter	Not listed
Stickers	SupportedPlace image stickers on any bubble with position, scale and rotation; sticker events inbound	Not listed
Formatted text	SupportedMarkdown rendered as native bold, italic, underline and strikethrough	Not supportedThe iMessage adapter treats iMessage as plain text
Attachments	SupportedFiles up to 100 MiB by default, including Live Photos	PartialPython adapter sends media by URL; inbound attachments are not parsed
Live Photos	SupportedHEIC still plus MOV companion uploaded as one Live Photo	Not listed
Rich link previews	Supportedrichlink() asks Messages to render its own preview	Not listed
Voice messages	Supported	Not listed
Contact cards	SupportedvCard or structured contacts, plus the bot's own native contact card	Not listed
Polls	SupportedCreate, vote, add options and receive poll events; all managed plans	Not listed
Chat backgrounds	Supported	Not listed
Location sharing	SupportedFind My requests and live location; Business plan	Not listed
iMessage apps	SupportedCustom and live app cards; iMessage mini apps on the Business plan	Not listed
Live app cards	SupportedEdit an app card in place and render live UI without a new bubble	Not listed
Sender name and photo	SupportedShares the agent's name and photo automatically; Business plan	Not listed
FaceTime calls	Not listed	Not listed
Delivery status	SupportedSent, delivered, read and send-error fields per message	Not listed
iMessage availability check	SupportedCheck if a number or email can get iMessage, SMS or RCS before sending	Not listed
Focus and Notify Anyway	SupportedCheck if a recipient has Focus on, then trigger Notify Anyway	Not listed
Numbers and delivery
Managed lines	SupportedSpectrum Cloud runs the Mac fleet; no Mac needed	Not listedSite lists iMessage on the hosted gateway; the live channel list (Oct 2026) does not include it
Dedicated numbers	Supported$250 per line per month on Business	Not listedHosted SMS uses your own Twilio or Telnyx number; no Caspian numbers in the live list
Shared numbers	SupportedFree and Pro route each user through a managed shared pool	Not listed
Bring your own number	SupportedYour own Apple ID when self-hosting on a Mac, and your own number for WhatsApp Business	SupportedYour own Twilio or Telnyx number for SMS, and your own Mac and Apple ID for iMessage
Line pooling	SupportedBusiness: auto-scale adds lines and a routing endpoint balances users	Not listed
SMS fallback	SupportedOn every plan per pricing; carrier rules apply to fallback traffic	Not listed
RCS fallback	Supported	Not listed
Outbound-first messaging	SupportedBusiness plan, up to 50 new contacts per line per day	Supportedinitiate and send start conversations on channels that allow it, SMS included
Calls on the iMessage number	SupportedPlace and receive SIP calls from the line people already text	Not listed
Other channels
SMS	BetaStandalone SMS and MMS numbers with 10DLC in the 2.0 beta; SMS fallback on iMessage lines today	SupportedBring your own Twilio or Telnyx number, hosted or self-hosted
RCS	PartialSent on the iMessage line when the recipient cannot get iMessage	Not listedSite lists RCS on the hosted gateway; not in the live channel list or the SDK catalog
WhatsApp	SupportedWhatsApp Business, one-to-one, on the Business plan	PartialSelf-host adapter with your own Meta WhatsApp Business app; not live on the hosted gateway
Telegram	Supported	SupportedYour own BotFather token, hosted or self-hosted
Slack	Supported@spectrum-ts/slack provider on npm and GitHub	SupportedShared Caspian app install on hosted, or your own tokens self-hosted
Email	BetaYour own domain with DKIM, SPF and inbound MX in the 2.0 beta	SupportedInstant hosted inboxes at agents.trycaspianai.com, or self-hosted
Phone calls	SupportedSIP calls on iMessage lines; the 2.0 beta adds calls on SMS numbers	PartialSelf-host Twilio voice adapter with TwiML; not live on the hosted gateway
Apple Messages for Business	BetaListed as available in the 2.0 beta	Not supportedNot offered
Unified channel API	SupportedOne Spectrum SDK across channels, and one REST model in the 2.0 beta	SupportedOne handler and one Thread and Message model across all channels
Developer tools
REST API	SupportedREST API for projects and lines; sending over REST in the 2.0 beta	SupportedHosted gateway /v1 API with bearer auth
TypeScript SDK	Supportedspectrum-ts, plus low-level iMessage and WhatsApp SDKs	Supportedcaspian-sdk on npm (MIT)
Python SDK	Betaphotonhq-api on PyPI, for the 2.0 beta API	Supportedcaspian-sdk on PyPI
Other SDKs	SupportedGo client for Advanced iMessage; Rust and Go clients for the 2.0 API	Not supportedPython and TypeScript only
CLI	Supported@photon-ai/cli manages projects, lines, users and billing	Supportedcaspian CLI: init, channels add, catalog, call, threads tail
Webhooks	Supported	SupportedHosted gateway POSTs events to your URL, or your process polls them
Signed webhooks	SupportedHMAC-SHA256, plus Standard Webhooks signatures	SupportedHMAC-SHA256 in X-Caspian-Signature; platform signatures are verified too
MCP server	SupportedHosted MCP server, plus an MCP server for the docs	SupportedHosted at api.trycaspianai.com/mcp; get_started mints a free sandbox key
Open source	SupportedMIT: spectrum-ts, imessage-kit and most SDKs	SupportedSite says MIT clients and AGPL server; root LICENSE is AGPL-3.0, README says Apache-2.0
Self-hosting	SupportedRun the open-source core on your own Mac and number, no Spectrum Cloud	SupportedAdapters run in your own process; the AGPL gateway server is in the repo
Local testing	SupportedTerminal chat UI provider, no phone or number needed	SupportedOffline fakes for every channel; handler rules are testable with no network
Custom channel providers	SupporteddefinePlatform plugs any interface into the same Spectrum API	SupportedSmall adapter interface for new channels; contributed adapters are invited
Event replay	SupportedCatch up on events after a disconnect from a durable sequence	PartialHosted events are polled by cursor; docs say to persist your own cursor across restarts
OpenTelemetry	SupportedOpt-in messaging traces in spectrum-ts, and traces in the 2.0 beta dashboard	Not listed
No-code integrations	Supportedn8n community nodes and a Dify plugin	Not listed
CRM integrations	Not listed	Not listed
Built for AI agents
Agent framework	SupportedSpectrum is a multi-channel agent framework with streaming replies	SupportedDeclarative on_message rules, overlap policies, acks and thread replies
Agent framework integrations	SupportedVercel Chat SDK, Mastra, LangChain, Convex and others	SupportedGuides for OpenAI Agents SDK, LangChain, LangGraph, CrewAI, Mastra, Vercel AI and more
Streaming replies	SupportedAI output streams into one iMessage bubble, edited in place	PartialPosts then edits as text arrives; one final post where a channel cannot edit, as on iMessage
Agent group chats	BetaAgents find other agents and add them to a group chat (2.0 beta)	Not listed
Human handoff	BetaA person can reply in a conversation from the 2.0 beta Inbox	Not listed
Audit logs	BetaAPI logs and traces in the 2.0 beta dashboard	Not listed
Message history API	SupportedList and get messages per chat	Supportedread_conversation MCP tool returns the full thread; threads tail in the CLI
Plans and compliance
Free plan	SupportedUp to 10 users on shared lines	SupportedSelf-hosting is free; the MCP get_started tool mints a free sandbox key
Public pricing	Supported	PartialNo pricing page; per-message costs appear in the open-source gateway code
No per-message fees	SupportedNo per-message fees for iMessage, WhatsApp or Telegram; SMS, voice and email are metered in the 2.0 beta	Not supportedPaid channels are billed per message from prepaid credit
Uptime SLA	SupportedContractual SLA on the Enterprise plan	Not listed
Isolated infrastructure	SupportedEach line runs in an isolated, dedicated environment	SupportedSelf-host mode runs every adapter in your own process
SOC 2 Type II	SupportedStated on photon.codes	Not listed
GDPR	SupportedPrivacy policy covers GDPR rights and SCC transfers	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

Which should you choose?

Choose Photon if you need group management, group name and photo, mentions and typing indicators.

Choose Caspian if its pricing fits better: it does not support anything here that Photon lacks.

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