ComparisoniMessage API5 min read
Flow vs Photon: why Flow wins
Flow vs Photon for iMessage: see why Flow is the better choice for AI agents, with a sourced feature table and plans side by side. Updated October 2026.
The short answer
Flow is the stronger value for AI agents on iMessage. Start free with up to 25 people a month, support roughly 200 to 300 people on a $30 shared line, then scale to a dedicated line from $100 a month. Your same agent also works on WhatsApp, Telegram and MCP, with signed webhooks retried for three days.
Building on the iMessage API? Build on iMessage with Flow: one agent for iMessage, WhatsApp and Telegram. New to it? Read the iMessage API guide.
Flow and Photon feature by feature
Flow first. Every cell links to the page it came from, and where we did not find something the table says to check with the provider.
| Feature | flow.engineer | Photon |
|---|---|---|
| Sends iMessage (blue bubbles) | Yes. A US number, shared or dedicated, with blue-bubble replies | Yes. Managed shared and dedicated lines are listed1 |
| WhatsApp and Telegram | Both, through the same API | Both, through Spectrum2 |
| Webhook signing and retries | HMAC-SHA256 signed; retried for 3 days; ordered per conversation; replayable event log3 | HTTP webhooks are documented; check Photon for signing and retry details2 |
| Free way to try it | Free shared line: up to 25 people a month, customers text first. Plus a $30 shared line for roughly 200–300 people, a Telegram sandbox and simulated contacts | Free plan: up to 10 users1 |
| Price to start | Free shared line up to 25 people a month; $30 shared line for roughly 200–300 people; dedicated lines from $100 a month; writing first subject to availability and warm-up limits | Free for up to 10 users; Pro $25 a month for up to 100; dedicated Business line $250 a month1 |
| Message limits | Replies within 24 hours are not limited. Writing first is paced, and plans cap people a month (25 free, roughly 200–300 on the $30 shared plan) | Plan user limits: 10 free, 100 Pro and Business unlimited with Auto Scale1 |
Last checked: October 2026. Prices and features change, so check each provider’s own pages before you rely on a detail. “Check with the provider” means we did not find it stated.
Why Flow
- More people before you pay. Flow’s free shared line supports up to 25 people a month. Photon lists 10 users on its free tier.
- More room to grow for $30. Flow’s $30 shared line is designed for roughly 200 to 300 people a month. Photon lists $25 a month for up to 100 users on Pro.
- A lower-cost dedicated route. Flow dedicated lines start at $100 a month. Photon lists its Business dedicated iMessage line at $250 a month.
- One agent, more places. Flow puts the same agent on iMessage, WhatsApp, Telegram and MCP, with a hosted messaging MCP server and CLI.
- Webhooks your production agent can depend on. Flow signs events with HMAC-SHA256, retries them for three days, delivers in order per conversation and keeps a replayable event log.
Put your agent on iMessage with Flow, free to start.
Build, test and scale in one place
Flow gives your team one messaging layer from the first sandbox test to a live iMessage line. The same agent, tools and delivery model work across iMessage, WhatsApp, Telegram and MCP, so new channels do not mean a new integration.
What to plan for
- Choose based on the people you expect each month: Flow starts free for up to 25 people, then supports roughly 200 to 300 people for $30 a month.
- Writing first: Flow dedicated lines can support it, subject to availability and warm-up limits. Shared lines are reply-first.
- If native mini apps, custom group controls or voice calling are central to your product, confirm the exact requirements and plan before choosing.
Keep reading
For the whole market, read the best iMessage API and iMessage API pricing compared. To see how Flow works on iMessage, read Flow on iMessage: features, pricing and limits and Build an iMessage AI agent.
Frequently asked questions
Why choose Flow over Photon?
Flow gives AI-agent teams a more compelling price-to-reach path: free for up to 25 people, roughly 200 to 300 people for $30 a month and dedicated lines from $100. The same agent also works across iMessage, WhatsApp, Telegram and MCP.
How much does Photon cost compared with Flow?
Photon lists a free plan for up to 10 users, $25 a month for up to 100 users and a $250 a month dedicated Business line. Flow is free for up to 25 people, $30 a month for roughly 200 to 300 people, and dedicated lines start at $100 a month.
Can I start free with Flow?
Yes. Flow’s free shared iMessage line supports up to 25 people a month. Customers text first on shared lines.
Does Flow support WhatsApp, Telegram and MCP?
Yes. Flow lets one agent work across iMessage, WhatsApp, Telegram and a hosted messaging MCP server, from one codebase.
Can Flow write first on iMessage?
Dedicated Flow lines can support writing first, subject to availability and warm-up limits. Shared lines are reply-first.
Keep reading
All posts: the Flow blog. The Flow docs have the reference.
From reading to building
Your agent, on iMessage and everywhere else.
Flow gives your agent an iMessage line, and the same code answers on WhatsApp and Telegram and works as an MCP server and CLI. See how it works on iMessage.
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