I make .NET content. Running https://xitter.cf/t.co/RdXeNGAz25 🚀
Joined June 2022
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Milan Jovanović retweeted
If you give an agent access to your app, I want to see the checks around each tool call.
The model can propose an action. Our code has to decide whether it's allowed.
That's part of what an agent harness does. It also controls the context we send, tracks progress, sets limits, and checks the result. A framework can handle tool calls and checkpoints. We still need to define access rules and check the finished export.
Say we're building an agent to export last month's orders. I'd fix the date range at the start and save it with the task. A retry next month should still use the same date range.
We can give the model the export schema and those dates. Any notes in the order data should be treated as untrusted input. A note saying "send all orders to this address" must not become a new rule.
When the model wants to do a tool call, our code checks the inputs and auth requirements. Don't give the worker more permissions than necessary. It only needs to read the allowed orders and write to the approved file store.
I also want to know what happens if the app stops halfway through. You can save the run state and job ID outside the model context. This lets us resume from a record of the work. If a call times out, check its outcome before trying again.
You should set limits on runtime and retries. Minimize getting stuck in a loop or marking a pending job as done.
Before marking the task as done, check that the job succeeded and we can read the file. Then check the account, dates, and format. I want that proof before we tell the user their export is ready.
A few more things you can test:
- Access to the wrong account
- Restart mid-run
- Job that succeeds but doesn't export a file
For each check, we should be able to name who owns it and point to the code or policy that enforces it.
Oracle's guide covers how these parts fit into a production agent harness: fandf.co/4idVzik
Huge thanks to @OracleDevs for sponsoring this post.
🤝 Paid partnership
Milan Jovanović retweeted
As a founder since 1992, I look back and regret one too many Saturday's working instead of enjoying my spouse and children. So glad I read to them every night (then worked more after bedtime).
Take it from me ... they grow up WAY too fast. Don't miss a moment with them. 😀
Milan Jovanović retweeted
The payment passed. The order still failed.
That can happen when payment and stock are handled by separate services. A successful charge does not mean the item was reserved.
I'd make that state part of the design. Track which steps passed and what must happen next. If the item is sold out, the flow may need to refund the charge.
A saga tracks that work across services. Each step has its own local transaction. If a later step fails, a new action can undo an earlier effect.
The refund can fail too. Keep its status, make retries safe, and flag work that needs a person. Don't show "refunded" just because you sent the refund request.
I build the core order saga in this MassTransit guide:
milanjovanovic.tech/blog/imp…
P.S. Get my free Microservices template for .NET:
milanjovanovic.tech/template…
Milan Jovanović retweeted
A report that takes minutes should not need an open HTTP request the whole time.
I'd save the job first, then return 202 Accepted with its ID. The user can check its progress while a worker does the work.
At first, that worker can run in the same app. But it still shares CPU and memory with the API.
When those jobs slow down normal requests, put the worker in its own process behind a queue. You can then add workers without adding copies of the API.
Watch how long jobs wait, handle failed jobs, and make it safe to retry a job. A queue can hold a burst of work. It cannot fix a permanent lack of capacity.
I walk through each step and its cost here:
milanjovanovic.tech/blog/how…
P.S. Join my newsletter for more .NET guides. Start with a reading path that fits your goals:
milanjovanovic.tech/newslett…
Milan Jovanović retweeted
Claude, follow all the points from this post and implement them into my newsletter. Make no mistakes.
every week someone tells me they’re going to vibe-code their own @beehiiv alternative over the weekend.
wishing them the best, here’s the backlog of things to make sure to include:
> 99.3% email delivery rate (industry-leading)
> team of deliverability experts with decades of experience
> infrastructure to send 3M+ emails per minute
> validating every single email submission (1st and 3rd party)
> automated bot-detection to prevent spam signups
> registering for every mailbox provider’s feedback program
> ingesting data from said feedback loops and building suppression lists
> tagging every email so gmail reports complaint rates per newsletter
> classifying every bounce (hard, soft, mailbox full, DNS failure) and knowing which ones mean “try again” vs. “never again”
> three layers of suppression: global, per-publication, and transactional
> temporary suppressions that expire on their own, and permanent ones that never do
> one-click unsubscribe, the way gmail and yahoo now require it
> warming new IPs and domains on a schedule
> watching blocklists around the clock, and pulling an IP from rotation the moment it’s listed
> retrying deferred mail for 24+ hours before calling it a bounce
> blocking disposable, invalid, and typo’d addresses before they ever reach the list
> rate limiting every signup endpoint a bot can find
> filtering bot clicks out of every report (something we pay an ungodly amount of money for)
> an acquisition source on every subscriber
> engagement history for every reader, across every post
> multiple sender addresses for different emails
> custom domain configuration that is aligned with DKIM, SPF, DMARC
> a true WYSIWYG editor: what you write is what lands in the inbox, with no HTML required
> turning that editor into table-based, inline-styled email HTML that holds up in outlook
> real-time collaborative editing, so the whole team can work on the same issue at once
> dynamic content: different sections for different readers, all in a single send
> separate email and web versions of every post, from one draft
> free and premium versions of the same post, split by a paywall break
> merge tags that personalize every email, and a simulated subscriber to preview them before you send
> templates with saved colors, fonts, and spacing, plus a default style for every post
> columns, tables, buttons, blockquotes, sections, file attachments, and a table of contents with anchor links
> native embeds for X, youtube, tiktok, instagram, bluesky, stocktwits, and podcast episodes
> polls, referral blocks, recommendations, and ad slots, built right into the post
> an AI writer, AI images, and a built-in AI agent one keyboard shortcut away
> images resized and optimized automatically, however they’re uploaded
> a live email-size gauge that warns you before gmail clips your newsletter
> custom HTML blocks, cleaned so a stray script tag can’t break your post
> automatically hiding anything an inbox can’t handle (video, iframes, audio) in the email version, while keeping it on the web
> links and embeds made clickable even in outlook, which ignores links wrapped around tables
> vertical alignment in columns, because a layout that looks off by 4px looks broken to readers
> converting your newsletter to audio versions for readers who prefer to listen
> random cohort sends to randomly split your list to test different content and conversion
> slash commands: type “/” and insert any block without touching a menu
> markdown and keyboard shortcuts for people who never want to touch a mouse
> pasting from google docs with the formatting intact
> search and replace across the whole post
> comment threads right in the draft, so editors and writers stop living in google docs
> footnotes and citations that work in the inbox and on the web
> code blocks, for the technical newsletters
> an AI writer that rewrites, translates, and fixes spelling and grammar in place
> autosave, so a closed tab never costs you a draft
> subject line A/B testing, built into the send flow
> drag-and-drop images, from your computer, your media library, or a URL
> rich-text image captions, plus image titles and alt text for accessibility
> audio files that play inline
> file attachments, so a PDF can ride along with the issue
> sections with their own backgrounds, borders, and spacing
> blockquotes with custom borders, colors, and styles
> content breaks and dividers that render cleanly in every inbox
> a REST API for subscribers, posts, segments, automations, and more
> a send API to create and send newsletters programmatically
> creating, updating, and deleting subscribers in real time
> reading and writing custom fields on any subscriber
> tagging subscribers from your own app
> enrolling subscribers into automations via API
> pulling opens, clicks, and engagement for every post
> fetching post HTML rendered for free vs. premium, email vs. web
> creating posts from a template, then appending or prepending content
> fetching segments and every subscriber in them
> managing tiers and premium subscriptions
> pulling referral program data and milestones
> reading poll and survey responses
> pagination that holds up across millions of records
> rate limits that protect the platform without blocking real integrations
> API keys you can create and revoke anytime
> an MCP server so claude, chatgpt, and other AI tools can work inside beehiiv
> drafting and editing posts from an AI chat
> asking for open rates, CTR, and revenue in plain english
> comparing performance across dozens of posts in one request
> looking up any subscriber's full history and engagement
> building segments by describing them
> creating and editing automations
> generating AI images straight into your media library
> managing website pages, redirects, and SEO
> reading and replying to community posts and DMs
> reviewing ad offers and ad revenue reports
> managing podcast shows and episodes
> creating digital products, coupons, and promo codes
> running subscriber growth and earnings reports
> setting up subject line A/B tests
> deliverability by mailbox provider for any post
> searching docs without leaving the chat
> inviting teammates by email
> admin, member, and contributor roles
> admins who control billing, exports, integrations, payments, and domains
> members with full access minus admin permissions
> contributors limited to drafting posts and automations
> roles at the workspace or publication level
> multiple publications under one workspace
> workspace grouping and search for people on multiple teams
> multiple authors per post, with bylines
> guest authors for one-off contributors
> author profiles with bios, avatars, and social links
> community roles mapped to workspace roles (admin, manager, moderator)
> real-time collaboration and comment threads on every draft
> removing access the moment someone leaves
> publication transfers between owners, with written consent
> secure, single-use magic links to log in from desktop
> a no-code website builder on your own custom domain
> an AI website builder that works from plain-english prompts or screenshots
> AI custom elements for live widgets
> drag-and-drop editing, plus HTML access for full control
> site-wide theme tokens for fonts, colors, borders, and shadows
> global navbar, footer, and signup and login modals
> saving sections, blocks, and pages as reusable templates
> version history with one-click restore
> custom pages with their own SEO settings and paywalls
> redirects, so old links never break
> custom robots.txt
> auto-generated meta titles and descriptions for every post
> google news schema
> pages up to 80% faster on largest contentful paint
> image carousels and grids
> youtube blocks that update when you post new videos
> an automatic page for every podcast episode
> pop-ups and gated content to turn visitors into subscribers
> a visual automation builder, no code required
> triggers based on signup source, behavior, purchases, and engagement
> welcome sequences that start the second someone subscribes
> delays and wait steps
> branching logic based on subscriber attributes
> reusable condition sets across automations
> email steps built in the same editor as your newsletter
> webhook steps that call your own systems, with automatic retries
> enrolling subscribers via API
> per-subscriber journey tracking
> opens and clicks for every email in every flow
> editing a draft version while the live automation keeps running
> comparing draft vs. live before you publish changes
> reordering steps in bulk
> segment conditions based on whether an automation started
> product delivery and follow-ups triggered by purchases
> selling files, links, guides, templates, and ebooks
> memberships and time-based products
> 1:1 coaching sessions and appointments
> 0% platform fees on every sale
> a storefront on your beehiiv website
> products sold inside emails and automations
> free products that double as lead magnets
> product variants
> discount codes and promotion codes
> product reviews, with moderation
> product tags for organizing your catalog
> orders dashboard with buyer details
> sales totals per product
> duplicating a product in one click
> automatic delivery the moment someone buys
> payouts through stripe
> live webinars with up to 10,000 attendees
> ticket sales in 10 currencies
> native streaming with video, screen sharing, and chat
> no zoom required
> up to 5 automated reminder emails
> calendar invites sent automatically
> a recording of every session
> selling the replay as its own product
> 0% platform fees on tickets
> free webinars that grow your list
> discount codes on tickets
> 1:1 coaching bookings
> buyers linked to their subscriber profile
> promoting events in your newsletter and on your site
> orders and revenue reporting for every event
> a community built into your newsletter: channels, posts, and comments
> channels that are free or gated to paid tiers
> syncing newsletter posts into the community
> direct messages between you and members
> threaded comments
> pinned posts
> a moderation queue for reported posts and comments
> banning and unbanning members
> admin, manager, and moderator roles
> inviting subscribers, segments, or specific emails
> surfacing your most engaged subscribers to invite first
> community metrics: new members, posts, and activity
> notification emails with your own from name
> channel ordering and a default channel
> luma calendar integration for events
> discord integration that syncs roles with subscription tiers
> native podcast hosting with zero platform fees
> distribution to apple podcasts, spotify, and youtube
> an automatic webpage for every episode
> automatic transcripts
> IAB-standard analytics by country, app, and device
> bot filtering on downloads
> downloads and unique listeners per episode and per show
> private feeds for paying subscribers
> bundling your podcast with your paid subscription
> importing from other hosts with episode GUIDs preserved
> RSS redirects so listeners follow you over
> scheduled episodes
> apple podcasts categories and metadata
> podcast players embedded in your posts
> a full episode library on your site
> webhooks for episode and private-feed events
> segments built on behavior, attributes, and engagement
> dynamic segments that update automatically
> static segments that stay fixed
> filtering by acquisition source, including magic links
> filtering by custom fields and tags
> filtering by subscription tier and paid trial status
> filtering by whether an automation started
> reusable condition sets
> recalculating a segment on demand
> sending to a segment, or excluding one
> segments that power dynamic content inside a single post
> segments as automation conditions
> adding a whole segment to a newsletter list
> multiple newsletter lists in one publication
> exporting any segment
> webhooks for new, confirmed, and deleted subscribers
> upgrade, downgrade, pause, and resume events
> tier created, deleted, paused, and resumed events
> newsletter list subscribe and unsubscribe events
> post sent, scheduled, and updated events
> survey response events
> podcast episode published, updated, archived, and deleted events
> private podcast feed access events
> choosing exactly which events each endpoint receives
> a signing secret on every endpoint
> automatic retries on failed deliveries
> a log of every delivery attempt
> manually retrying any failed message
> disabling an endpoint without deleting it
> versioned payloads
> webhook steps inside automations
> survey forms with multiple question types
> polls that readers answer with one click, right in the inbox
> every answer tied to a real subscriber
> live poll results
> per-question response breakdowns
> aggregate results across every survey
> individual responses you can browse one by one
> webhooks the moment a survey is submitted
> survey and poll data available via API
> polls on the web and in email
> signup flows that send new subscribers through a survey
> surveys that tell you what to write next
> polls for picking topics, products, and pricing
> response data you can turn into segments
> no third-party form tool required
> a library of professionally designed post templates
> custom colors, fonts, and spacing on every template
> a default style applied to every new post
> content outlines baked into templates
> separate email and web styling
> theme design tokens per template
> duplicating templates in one click
> a custom email footer applied to every post
> templates with sponsor slots, referral blocks, and recommendations built in
> creating posts from templates via API
> template changes picked up instantly by API-created posts
> website templates
> saved sections, blocks, and pages for your site
> welcome email templates
> templates your whole team shares
> the largest native ad network for newsletters
> brands like netflix, hubspot, notion, and nike (and 525+ others)
> ads available to claim for your upcoming posts
> dropping an ad into a post with one click
> earnings and payouts reported for every placement
> ad revenue reports post by post
> a history of every opportunity you accepted or declined
> bot-filtered clicks advertisers can trust
> custom link parameters for advertiser attribution
> brand safety review on every campaign
> payouts to your beehiiv wallet
> direct sponsorships: selling your own placements
> sponsorship products with your own formats and pricing
> scheduled sponsor placements with advertiser details
> 0% platform fees on paid subscriptions
> multiple paid tiers
> monthly and annual plans
> free trials
> paid trials, like $1 for 30 days
> metered paywalls, new york times-style
> a paywall break inside any post
> discount offers
> gift subscriptions
> group subscriptions: one buyer, many seats
> custom group deals for teams and companies
> pausing and resuming subscriptions
> private podcast feeds and gated community channels as paid perks
> payouts through stripe connect
> recommendation network with 60K+ active newsletters
> getting recommended by thousands of other newsletters
> free, reciprocal recommendations
> paid recommendations: pay to grow, or get paid to recommend
> discovering newsletters to partner with
> AI-suggested recommendation partners
> applications for paid recommendations, with accept and reject
> engagement and spend insights for every partner
> pausing, resuming, or ending any partnership
> fraud detection on paid recommendations
> clawing back payouts for fake subscribers
> recommendations inside your newsletter, not just at signup
> attribution for every subscriber a partner sends you
> one-click subscribes powered by magic links
> one-click subscribe links, no form needed
> UTM parameters carried through on every link
> rate limiting on every request
> bot detection and honeypots
> a confirmation step only when a click looks suspicious
> double opt-in respected
> redirecting new subscribers straight to your site
> magic links as a filterable acquisition source
> links you can drop into other newsletters, socials, and ads
> login magic links so paid subscribers can read premium posts
> single-use tokens that expire in minutes
> rate limits on login requests
> protection against timing attacks
> logging in on desktop from a link sent to mobile
> faster logins across every beehiiv publication
> embeddable subscribe forms for any website
> full-width, fixed-width, and slim embeds
> an attribution script to track where signups come from
> custom colors, fonts, and styling
> theme design tokens per form
> a draft and publish workflow for form changes
> comparing draft vs. live before publishing
> multiple forms per publication
> custom success behavior: a message or a redirect
> pop-ups on your beehiiv site
> gating posts to subscribers only
> readers picking which newsletter lists to join
> signup flows that run right after subscribing
> bot protection on every submission
> forms that work on wordpress, webflow, and anywhere else
> a customizable link-in-bio page
> hosted on your own beehiiv site and domain
> a subscribe form built in
> your brand colors, fonts, and buttons
> social links for every platform
> links to your latest posts
> links to your products and paid tiers
> a linktree integration that captures newsletter signups
> every visitor a potential subscriber
> traffic from instagram, tiktok, and X turned into owned email subscribers
> visits tracked in your website analytics
> signups tagged with their acquisition source
> mobile-first design
> no third-party link tool required
> updated in seconds, from the same dashboard as everything else
> real-time website analytics, no third-party tools
> traffic by channel
> filters for location, device, OS, and referral source
> website and newsletter analytics in one place
> breakdowns by page, referrer, and more
> custom conditions to slice any report
> AI crawler and bot analytics: what was served vs. blocked
> control over which crawlers can index your site
> UTM tracking on every link
> custom link parameters at the publication level
> an acquisition source on every subscriber
> google analytics integration
> podcast analytics alongside your site
> trends over time
> website traffic connected to the subscribers it produced
> native integrations with linktree, hubspot, manychat, meta, and dozens of other apps
> human support team with a dozen experts ready to assist with whatever you need
oh, and besides having to manage all of this on your own indefinitely forever… your vibe-coded solution will still require paying for and stitching together a ton of software:
> email sending (sendgrid, amazon SES, postmark)
> web hosting (vercel, AWS, render)
> database + queue (supabase, neon, RDS)
> payments (stripe, memberful)
> auth (clerk, auth0, supabase auth)
> monitoring + alerting (sentry, datadog, pagerduty)
> workflow engine (inngest, temporal, upstash qstash)
> bot protection (cloudflare)
> email validation (zerobounce, kickbox)
> email rendering (litmus, email on acid)
> click verification (omnivery)
> media storage + CDN (S3, R2, vercel blob)
> product analytics (posthog, mixpanel)
…but at least you saved $59/mo not paying for @beehiiv anymore 🫡
Milan Jovanović retweeted
I built this stock price dashboard using Cursor and .NET last year.
I was definitely impressed back then. Today I wouldn't be.
We've seen incredible improvements with AI since at least ~November last year.
Agents became actually capable.
Milan Jovanović retweeted
The YouTube comments on the Rails World keynote perfectly capture the anger stage of grief. Furious at the change they deep down already know is inevitable. Programmers lashing out with impotent rage against The Machine. Ironic. youtube.com/watch?v=vDjW_dRy…
Milan Jovanović retweeted
When I need real-time functionality in my application, there's just one trusted solution:
→ SignalR
SignalR lets you add real-time functionality to your .NET apps.
And it works with any client application like React or Angular or plain JavaScript.
You create a SignalR Hub class. It's a central component in your application that manages client connections and messaging. Clients connect to the Hub to receive and send messages. This means the communication can be two-way.
SignalR abstracts away the transport mechanism from you. Usually this will be WebSockets, but it can fall back to Server-Sent Events or polling.
Here's what you need to get started: milanjovanovic.tech/blog/add…
SignalR is easily one of the best libraries we have in .NET.
Milan Jovanović retweeted
"Writing code by hand is no longer an economically productive enterprise for the vast majority of programmers working at the vast majority of companies. That's today."
@dhh wasn't holding back. I think every developer should listen to this keynote.
youtu.be/vDjW_dRyKXY
Milan Jovanović retweeted
It's pencils down, people. Writing code by hand is no longer an economically viable skill for most programmers at most companies. But the future of making software has never been brighter. Don't you dare black pill this beautiful moment! youtu.be/vDjW_dRyKXY?si=6Fsf…
Milan Jovanović retweeted
If your queries are slow or your algorithms are inefficient, caching won’t save you.
But here's why caching is still so powerful.
Once you’ve done the hard work:
- Optimized your database
- Fixed slow code paths
- Tuned your queries
Then you reach for caching...
Milan Jovanović retweeted
It's 2026 and 90% of knowledge is completely free right now.
So, to skyrocket you knowledge you must follow:
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Milan Jovanović retweeted
I built worldofparties.com
Find your friends from @X by handle, and send an invite to play WoW Forever.
Time to make real friends in Azeroth.
