You can use this node script to post to Bluesky through it's API. You just need to set the username and app password and execute the script locally by running 'node index.js'.

index.js

const https = require('https');

function createBlueskyPost() {
    const BLUESKY_HANDLE = 'XXX';
    const BLUESKY_APP_PASSWORD = 'YYY';

    const data = JSON.stringify({
        identifier: BLUESKY_HANDLE,
        password: BLUESKY_APP_PASSWORD,
    });

    const options = {
        hostname: 'bsky.social',
        port: 443,
        path: '/xrpc/com.atproto.server.createSession',
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'Content-Length': data.length,
        },
    };

    const req = https.request(options, (res) => {
        let body = '';
        res.on('data', (d) => {
            body += d;
        });
        res.on('end', () => {
            const session = JSON.parse(body);
            postToBluesky(session.accessJwt, session.did);
        });
    });

    req.on('error', (e) => {
        console.error(e);
    });

    req.write(data);
    req.end();
}

function postToBluesky(accessJwt, did) {
    const post = {
        $type: 'app.bsky.feed.post',
        text: 'Playing around with the BlueSky API and Node',
        createdAt: new Date().toISOString(),
    };

    const data = JSON.stringify({
        repo: did,
        collection: 'app.bsky.feed.post',
        record: post,
    });

    const options = {
        hostname: 'bsky.social',
        port: 443,
        path: '/xrpc/com.atproto.repo.createRecord',
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'Content-Length': data.length,
            'Authorization': 'Bearer ' + accessJwt,
        },
    };

    const req = https.request(options, (res) => {
        let body = '';
        res.on('data', (d) => {
            body += d;
        });
        res.on('end', () => {
            console.log('Post created:', body);
        });
    });

    req.on('error', (e) => {
        console.error(e);
    });

    req.write(data);
    req.end();
}

createBlueskyPost();