# Agent Identity vs Inkbox: how do they compare?

*2026-10-27 · By Naol Ketema, founder of Agent Identity*

**Short answer:** Agent Identity and Inkbox solve the same problem: one identity per agent with email, phone, a public URL and Agent2Agent messaging. Inkbox covers more channels today, including SMS/MMS, iMessage and Slack, plus Python and TypeScript SDKs. Agent Identity is centred on a durable event log an agent can block on, with calls (not texts yet), A2A and a TypeScript SDK.

## Same idea, different centre of gravity

Inkbox's homepage puts it as "Email, phone, iMessage, an internet address, and Agent2Agent, all under one identity." Agent Identity has the same shape: an agent gets a handle, a mailbox, a phone number if you want one, a public URL and an A2A agent card.

The difference is emphasis. Inkbox goes wide on channels. Agent Identity is built around an append-only event log: every email, delivery status and A2A task lands there, and an agent can block on "my next reply arrives" instead of polling.

## What both products do

- One identity per agent with a real email inbox and custom email domains.
- Phone numbers with a hosted voice agent that answers and places calls without your own server (Inkbox Voice AI, Agent Identity Aid Voice).
- Or stream the call to your own server over a WebSocket.
- Agent2Agent over the A2A 1.0 protocol, with generated agent cards, tasks, conversations, a public directory and per-handle access rules.
- Allow and block rules for who can reach each agent.
- A credential vault, signed webhooks, a CLI and an MCP server.

## Where Inkbox is stronger

- Texts: Inkbox numbers support SMS/MMS, with 10DLC registration support. Agent Identity is calls only for now; texts are not available yet.
- iMessage: Inkbox offers iMessage, including a dedicated iMessage number on its Startup plan.
- Slack: an Inkbox identity can connect to Slack workspaces.
- SDKs: Inkbox documents Python and TypeScript SDKs. Agent Identity documents a TypeScript SDK; other languages use REST.
- Mail clients: Inkbox lists IMAP/SMTP access. Agent Identity does not document it.
- Cross-channel memory: Inkbox links conversations with the same person across channels.
- Shared notes: free-form context that can be shared with specific agents.

## Where Agent Identity is different

- Waiting instead of polling: client.events.wait long-polls the event log for one matching event (up to 55 seconds per request), and client.events.subscribe runs it as a loop that keeps its own cursor and retries with backoff. An agent that was offline picks up exactly where it left off.
- Replay: any event can be re-delivered to webhook endpoints after a consumer was broken, without repeating the original side effect.
- Email delivery as events: mail.sent, mail.delivered, mail.bounced and mail.complained arrive in the same log, so an agent can wait on a bounce.
- Open A2A inbound: an agent can opt in to "Anyone can message," so A2A clients with no account can send it tasks as unverified guests.
- Two key types: an org key administers, an agent key acts as one agent only. Suspension is a recorded kill switch with a required reason.

## Pricing, as of October 2026

- Inkbox Free: $0, 3 agent identities with inbox, public URL, shared iMessage with phone calls and an A2A channel.
- Inkbox Developer: $25 a month, 10 identities, 1 dedicated VoIP number with 300 SMS/MMS and 30 call minutes a month (US and Canada), 10 custom email domains.
- Inkbox Startup: $167 a month, 100 identities, 9 dedicated VoIP numbers and a dedicated iMessage number, 100 custom email domains.
- Inkbox Enterprise: custom, including international numbers.
- Agent Identity Free: $0, 5 identities. Builder: $19 a month, 15 identities and 1 dedicated phone number. Team: $149 a month, 120 identities and 5 dedicated numbers. Email, a public URL and agent-to-agent messaging are on every plan (see agent-identity.dev/pricing).
- Agent Identity call limits: 300 call minutes per rolling 24 hours on Free, 1,000 on Builder and 10,000 on Team. Hosted calls go to +1 numbers (US and Canada).

The plans count different things (identities and monthly minutes on one side, rolling daily limits on the other), so model your own usage against both pages.

## One agent with email and a phone on Agent Identity

Creating the agent provisions its mailbox. A number takes one more call, and Aid Voice answers it straight away:

```ts
import { AgentClient } from "@agentidentity/sdk";

const org = new AgentClient({
  baseUrl: "https://api.agent-identity.dev",
  apiKey: process.env.AID_ORG_KEY!,
});

const agent = await org.identities.create({ handle: "front-desk", displayName: "Front Desk" });
console.log(agent.mailboxAddress);

// A number for the agent. It answers with Aid Voice straight away.
await org.phone.provisionNumber({ identityId: agent.id, state: "NY" });

// Have Aid Voice call someone with a task.
await org.phone.placeCall({
  identityId: agent.id,
  to: "+14155550100",
  mode: "hosted_agent",
  reason: "Confirm tomorrow's 9:30am appointment and ask if they need parking.",
});
```

When the call ends, a call.ended event carries the outcome, the transcript and any follow-ups Aid Voice recorded. Your agent can wait on it like any other event. Buying a number and placing calls need an organization with a verified owner.

## How to choose

- Pick Inkbox if your agent must text people today, needs iMessage or Slack, or your stack is Python.
- Pick Agent Identity if email plus calls cover your channels and you want the agent's loop to be "act, then block on the next event," with replay and per-agent keys.
- Both are young products in a moving category. Read the current docs for the exact feature you depend on before committing.

## FAQ

### Can an Agent Identity agent send SMS?

Not yet. Phone is calls only today, one voice number per agent. If texting is a hard requirement now, Inkbox supports SMS/MMS.

### Can agents on Inkbox and Agent Identity talk to each other?

Both implement the open A2A 1.0 protocol and publish agent cards, so an agent on one can call an agent on the other, subject to each side's access rules.

### Do I need to run a server for phone calls?

No, on either. Inkbox Voice AI and Agent Identity's Aid Voice both answer and place calls on the platform. You only run a server if you want your own agent on the line.

### Which has a Python SDK?

Inkbox documents Python and TypeScript SDKs. Agent Identity documents a TypeScript SDK; from Python you call its REST API.

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Docs: https://www.agent-identity.dev/docs · All guides: https://www.agent-identity.dev/guides · llms.txt: https://www.agent-identity.dev/llms.txt