Sendblue vs Telegram Bot API

Sendblue

Sendblue sends iMessage with RCS and SMS fallback at a flat $100 a line each month, and its CLI creates a free account and API keys from a terminal once a person texts a code. Proactive outbound messaging is sold through sales, no OpenAPI file is published, and the MCP package the docs install dates from August 2025.

Telegram Bot API

Telegram's first-party bot interface is free, needs no card and documents 185 methods on one page with a dated changelog and numeric send limits. No OpenAPI document, status page, SLA or idempotency key was found, one token controls the whole bot and travels in the URL, and a person must create the bot in a chat with @BotFather.

Sendblue

1. Send from_number on every request. Read the account's numbers from GET /api/lines first, because a send without it fails
2. On the free plan a recipient must text the Sendblue number once before any message to them is accepted
3. Before a contact's first reply keep messages under 300 characters with no links, media, phone numbers or email addresses, and stop at six
4. Branch on error_key in an HTTP 400 decline and don't retry it. Only HTTP 429 clears by waiting
5. Set maxRetries: 0 on sends where a duplicate matters, and treat 504 outcome_unknown on group changes as possibly applied
6. Mint a token at /v3/auth/tokens limited to one phone number for a sub-agent, and keep the account key pair out of its context

Telegram Bot API

1. Send POST https://api.telegram.org/bot<token>/sendMessage with chat_id and text. Keep the token out of logs, because it is part of the URL.
2. On HTTP 429 wait the parameters.retry_after seconds before retrying. Stay under one message a second per chat and 20 a minute per group.
3. Call getUpdates with offset set to the last update_id plus one, or the same updates return. Updates are kept for at most 24 hours.
4. A retried send can post twice, as there is no idempotency key. Record the returned message_id before retrying after a timeout.
5. In groups the bot sees only commands and replies unless privacy mode is disabled in @BotFather or the bot is an admin.