blockkit

library2.1.3pypypi✓ verified 85d ago

Blockkit is a Python library for building user interfaces for Slack apps. It provides a fluent API with type hints and validation, allowing developers to compose Slack's Block Kit elements using Python classes, which reduces boilerplate and improves maintainability. The library is currently at version 2.1.3 and is actively maintained with frequent releases.

communication

pip install blockkit

github ↗package ↗

INSTALL

IMPORT

SIG · BLOCKKIT

blockkit

communicationpythonv2.1.3

Install

2.7s avg

Import

464ms

Disk

21MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.9.2 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.920 runs

installs and imports cleanly · install 0.0s · import 0.513s · 31.5MB

glibc

py 3.10–3.920 runs

installs and imports cleanly · install 2.7s · import 0.416s · 31MB

21MB installed

● package 21MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Modal

✓ from blockkit import Modal

Section

✓ from blockkit import Section

Message

✓ from blockkit import Message

Button

✓ from blockkit import Button

Confirm

✓ from blockkit import Confirm

This example constructs a Slack message with an approval request, including a button with a confirmation dialog. The `.build()` method validates the Block Kit structure, ensuring compliance with Slack's API specifications. The generated `message` object can be directly passed to the `blocks` parameter of `slack_sdk.WebClient.chat_postMessage`.

from blockkit import Message, Section, Button, Confirm message = ( Message() .add_block(Section("Please approve *Alice's* expense report for $42")) # Markdown detected automatically .accessory( Button("Approve") .action_id("approve_button") .style(Button.PRIMARY) .confirm( Confirm() .title("Are you sure?") .text("This action cannot be undone") .confirm("Yes, approve") .deny("Cancel") ) ) .thread_ts(os.environ.get('SLACK_THREAD_TS', '1234567890')) # Converts types automatically .build() # Validates everything: types, lengths, required fields ) # To send this message via Slack's WebClient, you would typically do: # from slack_sdk import WebClient # client = WebClient(token=os.environ.get("SLACK_BOT_TOKEN")) # response = client.chat_postMessage( # channel="C12345", # blocks=message # Blockkit objects are directly serializable to JSON dicts expected by Slack SDK # ) print(message)

Debug

Known issues

breakingVersion 2.0.0 was a complete rewrite of the library with a new fluent API and zero dependencies. Code written for versions prior to 2.0.0 will not be compatible.

fix

Rewrite Block Kit UI construction using the new fluent API. Refer to the official documentation for migration guidance and new syntax.

affects: <2.0.0

gotchaWhen using interactive components (e.g., buttons, select menus) within Blockkit, ensure your Slack App's 'Interactivity & Shortcuts' feature has a properly configured 'Request URL'. Without this, Slack cannot send interaction payloads (like `block_action`) to your application.

fix

Configure the 'Request URL' in your Slack App settings (api.slack.com/apps) under 'Interactivity & Shortcuts'. Ensure your server endpoint correctly receives and processes Slack's `POST` requests.

affects: All

gotchaSlack's 'mrkdwn' formatting has subtle differences from standard Markdown. While Blockkit aims to handle common cases automatically, be aware of specific syntax requirements for elements like links (`<url|text>`) or bold (`*text*`).

fix

Refer to Slack's 'Formatting text for app surfaces' documentation for exact 'mrkdwn' syntax. Blockkit's automatic detection usually works, but manual review for complex formatting may be needed.

affects: All

Errors

Common errors & fixes

slack.errors.SlackApiError: The request to Slack API Failed. The server responded with: {'ok': False, 'error': 'invalid_blocks_format'}

The generated Block Kit JSON structure is malformed or does not adhere to Slack's API specifications (e.g., missing required fields, incorrect types, invalid nesting).

fix

Ensure all Blockkit components are correctly instantiated and chained according to the library's fluent API. The `.build()` method performs validation; check its output for detailed errors. Use Block Kit Builder (api.slack.com/tools/block-kit-builder) to prototype and validate your structure.

Not receiving block_action payload when interacting with a Slack Block Kit modal/message

The interactive elements (e.g., buttons) are not correctly configured within an `ActionsBlock` or `InputBlock` with `dispatch_action: true`, or the Slack App's 'Request URL' for interactivity is not set up or reachable.

fix

Verify that your Slack App's 'Interactivity & Shortcuts' 'Request URL' is correctly set and your server is publicly accessible. Also, ensure interactive elements in your Blockkit structure are properly nested within `Actions` blocks or `Input` blocks configured to dispatch actions.

Upgrade

Version history

2.1.3latest on PyPI · released Jan 18, 2026

Audit

Dependencies

No dependency data recorded yet.

Agent activity

41 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/imryche/blockkit ↗

packagehttps://pypi.org/project/blockkit/ ↗