Photon vs Signal House

Photon supports 75 of the 77 features compared here, and Signal House supports 24.

Feature comparison

Feature	Photon	Signal House
iMessage messaging
iMessage	SupportedManaged cloud lines, or your own Mac with the local provider	Not supportedNo iMessage support
Group chats	SupportedOn the Business plan (dedicated lines)	Not supported
Group management	SupportedCreate groups and add, remove or leave members; Business plan (dedicated lines)	Not supported
Group name and photo	SupportedRename groups and set group photos; Business plan (dedicated lines)	Not supported
Mentions	SupportedSend @mentions in multipart messages and read mention ranges on inbound	Not supported
Tapbacks	SupportedSix native tapbacks plus emoji reactions, send and receive	Not supported
Threaded replies	Supported	Not supported
Typing indicators	Supported	Not supported
Read receipts	SupportedMark chats read and receive read events; group receipts are best-effort	Not supported
Edit and unsend	SupportedEdit within 15 minutes and unsend within 2 minutes (Apple limits)	Not supported
Message effects	SupportedAll bubble and screen effects, including invisible ink	Not supported
Animated text effects	SupportedPer-range effects such as bloom, shake, explode and jitter	Not supported
Stickers	SupportedPlace image stickers on any bubble with position, scale and rotation; sticker events inbound	Not supported
Formatted text	SupportedMarkdown rendered as native bold, italic, underline and strikethrough	Not supported
Attachments	SupportedFiles up to 100 MiB by default, including Live Photos	Not supported
Live Photos	SupportedHEIC still plus MOV companion uploaded as one Live Photo	Not supported
Rich link previews	Supportedrichlink() asks Messages to render its own preview	Not supported
Voice messages	Supported	Not supported
Contact cards	SupportedvCard or structured contacts, plus the bot's own native contact card	Not supported
Polls	SupportedCreate, vote, add options and receive poll events; all managed plans	Not supported
Chat backgrounds	Supported	Not supported
Location sharing	SupportedFind My requests and live location; Business plan	Not supported
iMessage apps	SupportedCustom and live app cards; iMessage mini apps on the Business plan	Not supported
Live app cards	SupportedEdit an app card in place and render live UI without a new bubble	Not supported
Sender name and photo	SupportedShares the agent's name and photo automatically; Business plan	Not supported
FaceTime calls	Not listed	Not supported
Delivery status	SupportedSent, delivered, read and send-error fields per message	Not supported
iMessage availability check	SupportedCheck if a number or email can get iMessage, SMS or RCS before sending	Not supported
Focus and Notify Anyway	SupportedCheck if a recipient has Focus on, then trigger Notify Anyway	Not supported
Numbers and delivery
Managed lines	SupportedSpectrum Cloud runs the Mac fleet; no Mac needed	Not supportedNo iMessage support
Dedicated numbers	Supported$250 per line per month on Business	SupportedLocal 10DLC and toll-free numbers at $1.00/month, plus short codes
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	SupportedPort-in requests by API, handled by staff; llms.txt also lists BYON
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 supportedNo iMessage support
RCS fallback	Supported	Not supported
Outbound-first messaging	SupportedBusiness plan, up to 50 new contacts per line per day	SupportedSends from numbers on an approved 10DLC campaign
Calls on the iMessage number	SupportedPlace and receive SIP calls from the line people already text	Not supportedNo iMessage support
Other channels
SMS	BetaStandalone SMS and MMS numbers with 10DLC in the 2.0 beta; SMS fallback on iMessage lines today	SupportedSMS, MMS and group messages on 10DLC, toll-free and short code, North America
RCS	PartialSent on the iMessage line when the recipient cannot get iMessage	Not supportedOn the roadmap (Coming Soon page)
WhatsApp	SupportedWhatsApp Business, one-to-one, on the Business plan	Not supported
Telegram	Supported	Not supportedNot offered
Slack	Supported@spectrum-ts/slack provider on npm and GitHub	Not supportedNot offered as a channel; support runs in Slack
Email	BetaYour own domain with DKIM, SPF and inbound MX in the 2.0 beta	Not supportedNot offered
Phone calls	SupportedSIP calls on iMessage lines; the 2.0 beta adds calls on SMS numbers	SupportedProgrammable calls, WebRTC softphone tokens, SIP trunks and call logs
Apple Messages for Business	BetaListed as available in the 2.0 beta	Not supportedOn the roadmap (Coming Soon page)
Unified channel API	SupportedOne Spectrum SDK across channels, and one REST model in the 2.0 beta	PartialSMS, MMS and group messages share the Messages API; voice is a separate service
Developer tools
REST API	SupportedREST API for projects and lines; sending over REST in the 2.0 beta	Supported
TypeScript SDK	Supportedspectrum-ts, plus low-level iMessage and WhatsApp SDKs	Supported@signalhousellc/sdk, with a webhook verifier
Python SDK	Betaphotonhq-api on PyPI, for the 2.0 beta API	Supportedsignalhouse on PyPI
Other SDKs	SupportedGo client for Advanced iMessage; Rust and Go clients for the 2.0 API	Supported.NET, Go, PHP, Ruby and Rust
CLI	Supported@photon-ai/cli manages projects, lines, users and billing	Not listed
Webhooks	Supported	SupportedMessage, campaign, number health and other events
Signed webhooks	SupportedHMAC-SHA256, plus Standard Webhooks signatures	SupportedHMAC-SHA256 over timestamp and body, with secret rotation
MCP server	SupportedHosted MCP server, plus an MCP server for the docs	SupportedRemote MCP server with OAuth; sends SMS and MMS, buys numbers, registers campaigns
Open source	SupportedMIT: spectrum-ts, imessage-kit and most SDKs	Not supportedClosed platform; SDKs are public on GitHub
Self-hosting	SupportedRun the open-source core on your own Mac and number, no Spectrum Cloud	Not supportedHosted service only
Local testing	SupportedTerminal chat UI provider, no phone or number needed	PartialPOST /agent/messages chats with a hosted agent over the API, no phone needed
Custom channel providers	SupporteddefinePlatform plugs any interface into the same Spectrum API	PartialHeld agent replies can be claimed and delivered through your own channel
Event replay	SupportedCatch up on events after a disconnect from a durable sequence	PartialThree quick retries; missed messages can be re-read from the message log API
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	SupportedGoHighLevel app and Make.com
CRM integrations	Not listed	SupportedNative HubSpot SMS and MMS app; Salesforce is on the roadmap
Built for AI agents
Agent framework	SupportedSpectrum is a multi-channel agent framework with streaming replies	SupportedAgent profiles with tools, knowledge and per-channel settings for webchat, SMS and voice
Agent framework integrations	SupportedVercel Chat SDK, Mastra, LangChain, Convex and others	Not listed
Streaming replies	SupportedAI output streams into one iMessage bubble, edited in place	Not listed
Agent group chats	BetaAgents find other agents and add them to a group chat (2.0 beta)	PartialGroup messages to several recipients from one 10DLC number; not agent-specific
Human handoff	BetaA person can reply in a conversation from the 2.0 beta Inbox	SupportedReview mode holds each agent reply as a draft for a person to approve, reject or claim
Audit logs	BetaAPI logs and traces in the 2.0 beta dashboard	Not listed
Message history API	SupportedList and get messages per chat	SupportedMessage logs with filters, plus stored agent conversations
Plans and compliance
Free plan	SupportedUp to 10 users on shared lines	Partial$25 credit for new accounts
Public pricing	Supported	Supported
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 supportedPer segment, plus carrier fees at cost
Uptime SLA	SupportedContractual SLA on the Enterprise plan	Not listed
Isolated infrastructure	SupportedEach line runs in an isolated, dedicated environment	Not listed
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 iMessage, group chats, group management and group name and photo.

Choose Signal House if you need CRM integrations.

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