---
title: "Latest reads"
description: "The engineering internet, summarised so you can actually read it."
---

# Latest reads
> The engineering internet, summarised so you can actually read it.

## Articles

### [Let AI Entertain You: Increasing User Engagement with Generative AI and Rejection Sampling](https://yomu.fyi/post/let-ai-entertain-you-increasing-user-engagement-with-generative-ai-and.md)
- Company: [Nextdoor](https://yomu.fyi/company/nextdoor.md)
- Author: Jaewon Yang
- Published: Oct 16, 2023
- Type: Problem & solution

Nextdoor implemented a generative AI framework to improve email notification subject lines for its New and Trending emails. Using off-the-shelf ChatGPT API outputs directly resulted in marketing-like phrases, hallucinations, and lower click-through rates compared to original user-generated post snippets. To resolve this, the team prompted the language model strictly to extract authentic post phrases without rewriting, eliminating hallucinations while preserving the original tone. Nextdoor then introduced a rejection sampling mechanism featuring a dedicated reward model that predicts user engagement and accepts generated subjects only when their score exceeds the user-written baseline. This combined system lifted sessions by 1%, boosted Weekly Active Users by 0.4%, and increased advertising revenue by 1%.


### [Our problems](https://yomu.fyi/post/our-problems.md)
- Company: [Cursor](https://yomu.fyi/company/cursor.md)
- Author: Sualeh Asif
- Published: Oct 12, 2023
- Type: Explainer

The post lays out problems Cursor is working on in AI-assisted coding, from selecting relevant context in large codebases to making edits and finding bugs. It proposes collecting 500k tokens from editor sources and using a custom, fast reranker to reduce that context to 8k tokens, while reporting 1.4 billion vectors and 150,000 codebases indexed as of October 12, 2023. Other planned capabilities include a constrained few-step agent that searches, writes, and runs code with feedback, passive and active bug finding, and larger edits presented in real time. Future ideas include time-warp predictions, code understanding in model weights, reader and pseudo-code modes, and automatic stack-trace fixes. The list is explicitly not a final roadmap because new ideas and priorities change, and the post also invites interested people to join the company.


### [Finding the right balance of speed and security through just-in-time access to cloud resources](https://yomu.fyi/post/finding-the-right-balance-of-speed-and-security-through-just-in-time-a.md)
- Company: [Ramp](https://yomu.fyi/company/ramp.md)
- Author: Julien Colombain
- Published: Oct 11, 2023
- Type: Problem & solution

Ramp’s rapid growth exposed problems in its AWS access model: three broad roles created persistent production access for some senior engineers while junior engineers depended on seniors for queries. The team first reorganized permissions into more than 20 team-specific AWS Identity Center groups, each backed by permission sets and a Terraform module that presents IAM configuration through human-readable resource lists. It then introduced just-in-time access through ConductorOne by pairing each non-production role with an elevated production role, removing standing production access and provisioning entitlements through AWS SSO group membership. Team-owned requests were automatically approved, while cross-team requests went to the relevant tech lead, with temporary access and backup approval handling described in the design. The resulting model reduced exposure, preserved fast access to needed resources, and recorded production activity for accountability and audit purposes.


### [Scaling marketing for merchants with targeted and intelligent promos](https://yomu.fyi/post/scaling-marketing-for-merchants-with-targeted-and-intelligent-promos.md)
- Company: [Grab](https://yomu.fyi/company/grab.md)
- Author: Sharon Teng
- Published: Oct 11, 2023
- Type: Problem & solution

Grab previously relied on globally assigned, heuristic promotional campaigns where all users could redeem offers until limits were reached. This lack of targeting and customisation failed to optimize promo spending or meet specific merchant business objectives. To solve this, the engineering team built Bullseye, an automated AI-driven promotional assignment system that customises and assigns offers to consumers. The architecture integrates an operations user interface, backend services, Amazon S3 storage, and Spark jobs executing a suite of predictive modules including eater segmentation, campaign impact simulation, and customer response modeling. Since deploying Bullseye in 2021, the system has increased food campaign sales while decreasing promo spend across food and Mart campaigns.


### [Picking Low Hanging Fruit](https://yomu.fyi/post/picking-low-hanging-fruit.md)
- Company: [Ramp](https://yomu.fyi/company/ramp.md)
- Author: Rodda John, Luke Zeller, Rahul Sengottuvelu
- Published: Sep 30, 2023
- Type: Explainer

The page identifies the item with the title “Picking Low Hanging Fruit,” but provides no accompanying article narrative or technical subject matter. Instead, it consists of HTML metadata, favicon and RSS references, JavaScript and stylesheet asset links, a notice that JavaScript must be enabled, and analytics snippets. The metadata names the site “Ramp Builders” and labels its RSS feed “Ramp Builders Blog”; the scripts reference Segment analytics and a Google Analytics configuration. No problem, implementation, experiment, outcome, or conclusion is described, so the title’s meaning and the post’s intended subject cannot be established from this text. There is no basis in the available material for a more specific technical classification.


### [Why You Should Migrate to OAuth 2.0 From Static API Tokens](https://yomu.fyi/post/why-you-should-migrate-to-oauth-2-0-from-static-api-tokens.md)
- Company: [Okta](https://yomu.fyi/company/okta.md)
- Author: Alisa Duncan
- Published: Sep 25, 2023
- Type: Explainer

Static API tokens provide a simple way to authorize calls to protected third-party APIs, but their long lifetimes, broad permissions, and lack of user context create security and auditing risks. OAuth 2.0 addresses these limitations through a centralized authorization server that issues short-lived access tokens, which clients send in the Authorization header with the Bearer scheme. The post describes Client Credentials for service-to-service interactions and explains that scopes can distinguish permissions such as okta.users.read and okta.users.write; other configurations support task-based automation and user access through web applications. Migration guidance recommends implementing new calls with OAuth 2.0, applying least privilege, testing expiration and error handling, and securing private keys and JWKS generation before production deployment.


### [Stepping up marketing for advertisers: Scalable lookalike audience](https://yomu.fyi/post/stepping-up-marketing-for-advertisers-scalable-lookalike-audience.md)
- Company: [Grab](https://yomu.fyi/company/grab.md)
- Author: William Wu
- Published: Sep 22, 2023
- Type: Problem & solution

Grab's legacy lookalike audience generation platform suffered from long creation SLAs of two working days, high costs, and low weekly update frequencies. To resolve these bottlenecks, the engineering team designed an embedding-based platform powered by an in-memory retrieval service and automated update pipelines. The system creates audience representations by averaging constituent passenger embeddings, determining user membership through real-time cosine score thresholds. To eliminate feature store latency while fitting all embeddings into memory, a hash-based compression method cuts passenger embedding storage needs by roughly 90%. Consequently, audience availability dropped to within 15 minutes of campaign creation, audience generation costs fell by 98%, and ad impressions and clicks doubled.


### [The 10 teamwork skills everyone needs](https://yomu.fyi/post/the-10-teamwork-skills-everyone-needs.md)
- Company: [Notion](https://yomu.fyi/company/notion.md)
- Author: Maggie Gowland
- Published: Sep 19, 2023
- Type: Explainer

Workplace collaboration depends on interpersonal skills that help groups interact productively while preserving individuals’ independence. The post identifies ten core capabilities: communication, active listening, respect, conflict resolution, accountability, delegation, problem-solving, open-mindedness, self-awareness, and trust. It explains how these skills address practical team problems, from siloed information and excessive workloads to miscommunication, unresolved disagreements, and emotional reactions, while noting that effective communication requires balance rather than constant messages or meetings. Improvement relies on setting one goal at a time, requesting honest feedback, and observing effective teammates; the post also recommends tailoring a CV’s examples to an employer’s values and keeping entries brief. Notion is presented as a platform for roadmaps, one-on-ones, team pages, and wikis.


### [The AR Measuring Box: Etsy's answer to Big Tape Measure](https://yomu.fyi/post/the-ar-measuring-box-etsy-39-s-answer-to-big-tape-measure.md)
- Company: [Etsy](https://yomu.fyi/company/etsy.md)
- Author: Pedro Michel
- Published: Sep 18, 2023
- Type: Explainer

Etsy extended its iOS Wall View experience into an AR measuring tool that represents listings as scaled 3D boxes, allowing shoppers to judge an item's size and fit in their space. The work addressed the difficulty of creating models for millions of customizable, often handmade items by improving dimension extraction instead. A server-side regex parser reads titles, descriptions, customization information, overviews, and variations, handling unit variants, localization, special characters, fractions, conversions, complex imperial measurements, and duplicate values while prioritizing structured fields and caching results. In iOS, the measuring box uses SceneKit’s SCNBox and SCNNode labels, supports movement and rotation, and uses LiDAR-derived meshes for environment occlusion. The resulting feature adds real-size AR functionality to nearly a million Etsy items, viewed by tens of thousands of users weekly.


### [How Ramp Accelerated Machine Learning Development to Simplify Finance](https://yomu.fyi/post/how-ramp-accelerated-machine-learning-development-to-simplify-finance.md)
- Company: [Ramp](https://yomu.fyi/company/ramp.md)
- Author: Peyton McCullough
- Published: Sep 15, 2023
- Type: Problem & solution

Ramp describes how its machine-learning organization used Metaflow to shorten the path from prototype to production for models spanning credit risk, fraud, growth, product, and Ramp Intelligence. Its initial riskiness model exposed long vendor-managed jobs, weak logging, limited Docker support, and substantial platform friction; the model took months to build. Metaflow, with developer-experience improvements, lets teams define flows in Python, run them locally or on AWS Batch, visualize results with cards, and connect production execution to Step Functions and Airflow. Ramp chose AWS-managed infrastructure, initially using Fargate before encountering startup and resource constraints, and later built a MetaflowOperator to simplify Airflow triggering and log access. After adoption, Ramp shipped eight additional models in ten months, recorded more than 6,000 Flow runs, and reports that data scientists can largely self-service while platform engineers spend less time debugging infrastructure.


### [Enterprise Maturity Workshop: Automate with no](https://yomu.fyi/post/enterprise-maturity-workshop-automate-with-no.md)
- Company: [Okta](https://yomu.fyi/company/okta.md)
- Author: Max Katz
- Published: Sep 15, 2023
- Type: Tutorial

This tutorial shows how to extend a SaaS Todo application with a weekly organizational report using Okta Workflows, a no-code automation platform. It adds an API service to the application, exposes the local app through a tunnel, and configures a scheduled flow to retrieve all todo items. A helper flow processes the returned list with a Reduce card, carrying accumulated text in a memo field before producing one summary for the Gmail Send Email card. The report is sent automatically by email after the items are combined. The workshop concludes by enabling both flows and testing the automation, while noting that the local setup is for demonstration and that a real-world application would be deployed in the cloud.


### [Skip the API, Ship Your Database](https://yomu.fyi/post/skip-the-api-ship-your-database.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Sep 13, 2023
- Type: Explainer

The post describes an unexpected use for LiteFS, a distributed SQLite database: replacing service-to-service APIs with read-only database replicas. Typical APIs require anticipating access patterns; shipping the full database lets clients use SQL joins, aggregation, and windowing locally, while one-way LiteFS replication avoids chatty gossip and is simple to configure with an upstream primary hostname. Moving queries to client hardware removes shared service compute contention and the need for tenant rate limiting and timeouts, but replicas cannot handle mutations and raw schema changes create looser contracts, mitigated by backward-compatible changes and views. Data access is harder to restrict in multi-tenant databases, so per-tenant SQLite files are a suggested workaround. The approach is positioned for specific read-heavy use cases, potentially including local copies of Stripe or GitHub data, with event buses such as Kafka generating per-tenant databases.


### [Automated Sentry Error Tracking](https://yomu.fyi/post/automated-sentry-error-tracking.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Sep 12, 2023
- Type: Announcement

Fly.io announces Sentry as the default error-monitoring tool for its applications, with new deployments receiving an automatically provisioned Sentry project and existing apps using flyctl ext sentry create. Each organization receives one year of monthly Team Plan credits covering 50,000 error events, 100,000 performance units, 500 session replays, and 1GB of attachment storage. For Rails apps, flyctl launch installs the required gems, creates initializers, and sets the SENTRY\_DSN secret, allowing boot failures, memory exhaustion, exceptions, latency issues, and crashes to reach Sentry. The post demonstrates a deliberately raised Ruby exception, then uses flyctl apps errors to open the Sentry issue dashboard and identify the bug; planned extensions include release tracking and out-of-memory events.


### [Building a ShopifyQL Code Editor](https://yomu.fyi/post/building-a-shopifyql-code-editor.md)
- Company: [Shopify](https://yomu.fyi/company/shopify.md)
- Author: 2023-10-18
- Published: Sep 11, 2023
- Type: Tutorial

ShopifyQL Notebooks, released in October 2022, is a first-party app that lets merchants analyze shop data. To give its guided code-editing experience, Shopify used CodeMirror, which did not natively support ShopifyQL. Because ShopifyQL’s grammar is defined in ANTLR and generates Go and TypeScript code, while the language server follows Microsoft’s Language Server Protocol (LSP), the existing client and server language infrastructure was retained. A custom adapter passes queries to the language server, converts its incremental five-integer token descriptors into CodeMirror-compatible offsets, and reshapes them into a buffer of Lezer nodes for parse-tree construction. The resulting integration supports syntax highlighting, code completion, linting, and hover tooltips through CodeMirror plugins, while using its internal parse tree to inform editing behavior.


### [From Pre-trained to Fine-tuned: Nextdoor’s Path to Effective Embedding Applications](https://yomu.fyi/post/from-pre-trained-to-fine-tuned-nextdoor-s-path-to-effective-embedding.md)
- Company: [Nextdoor](https://yomu.fyi/company/nextdoor.md)
- Author: Karthik Jayasurya
- Published: Sep 7, 2023
- Type: Problem & solution

Nextdoor transitioned its ranking and recommendation pipelines from traditional continuous and discrete interaction features to transformer-based representation learning. The engineering team deployed pre-trained Sentence-BERT models to generate multilingual post and comment representations, which were aggregated daily by interaction type to form user embeddings. To improve search recall, the team fine-tuned sentence transformers on unlabeled query session logs using contrastive learning and integrated HNSWlib for approximate nearest neighbor retrieval. Subsequent iterations incorporated labeled feedback, BERTopic for coarse personalization, and experiments with CLIP image embeddings. Infrastructure scaling challenges were addressed by performing embedding transformations directly within FeatureStore and optimizing feature payload formats to minimize microservice network bandwidth.


### [The So-fine Real-time ML Paradigm](https://yomu.fyi/post/the-so-fine-real-time-ml-paradigm.md)
- Company: [Etsy](https://yomu.fyi/company/etsy.md)
- Author: Kyle Gallatin
- Published: Sep 5, 2023
- Type: Problem & solution

During Etsy’s CodeMosaic hackathon, a team investigated stateful training and online learning to reduce the roughly 40-hour delay between user actions and model-weight updates. They split the work across real-time training data, an incremental-learning service, and evaluation, using Etsy’s Beacon Main Kafka stream, Kafka SQL, Rivulet, and TensorFlow-based Ads models. The data team joined multiple sources despite Avro schema difficulties, while the service team loaded an older model and nearly implemented incremental weight updates; the planned head-to-head evaluation against daily batch training was not completed. The project estimated that replacing daily cold-start training for four ads models could save about $212,000 annually in Google Cloud costs, with possible metric gains from earlier events. Production would still require infrastructure and safeguards against sudden performance degradation.


### [We're Living in a Passwordless World](https://yomu.fyi/post/we-re-living-in-a-passwordless-world.md)
- Company: [Okta](https://yomu.fyi/company/okta.md)
- Author: Alisa Duncan
- Published: Aug 30, 2023
- Type: Tutorial

Passwords and SMS one-time passwords are presented as vulnerable authentication methods, while the post explains how FIDO and W3C standards support passwordless, phishing-resistant sign-in. It contrasts passwords, SMS OTP, TOTP, and U2F security keys, then introduces FIDO2, which combines WebAuthn with CTAP2 and asymmetric cryptography. The registration and authentication walkthrough describes the Relying Party, client, server, browser, and authenticator interactions, including device-based PINs and biometrics. Passkeys build on WebAuthn and can work across compatible browsers and devices, with migration within some vendor ecosystems described as an additional convenience. Developers can call navigator.credentials.create and navigator.credentials.get directly or use libraries, while Identity Providers such as Okta can provide FIDO2 support through configuration.


### [Building hyperlocal GrabMaps](https://yomu.fyi/post/building-hyperlocal-grabmaps.md)
- Company: [Grab](https://yomu.fyi/company/grab.md)
- Author: Adriana Lazar
- Published: Aug 30, 2023
- Type: Problem & solution

Southeast Asia presents unique mapping challenges, including fast-changing road restrictions, new roads appearing rapidly, and severe traffic congestion. To address these conditions, GrabMaps integrates hyperlocal data derived from local team knowledge, rides and deliveries GPS pings, and KartaView imagery with OpenStreetMap data. The pipeline downloads OpenStreetMap .pbf files for Asia and converts them into Parquet format using a Parquetizer. GrabMaps processes spatial data using Apache Spark and bi-directional graphs divided by geohash to detect complex features such as intersection links based on road parallelism, naming, direction, and shape geometry. Tagging these intersection links enables downstream navigation services like GrabNav to calculate shorter routing alternatives and provide more accurate pricing.


### [Tracking Application-Level Consistency with LiteFS](https://yomu.fyi/post/tracking-application-level-consistency-with-litefs.md)
- Company: [Fly.io](https://yomu.fyi/company/fly-io.md)
- Published: Aug 30, 2023
- Type: Problem & solution

LiteFS must keep an application’s view consistent when a write reaches a primary and a subsequent read is served by a lagging replica. The project first considered making applications track each database’s replication position—a TXID paired with a post-apply checksum—and wait for replicas to catch up, but rejected that complexity and abandoned language-specific libraries. It instead introduces a thin HTTP proxy in front of the application: method-based request inspection routes writes to the primary, attaches the committed TXID in a cookie, and delays reads until the local replica reaches that position or times out. The proxy also exposes lag through health checks, allowing Fly.io to remove unhealthy replicas from rotation and restore them after reconnection. This design provides read-your-writes guarantees with little application change, but depends on cookies and conventional HTTP request/response traffic, limiting use with some applications and websocket-heavy frameworks.


### [Women’s World Cup 2023: How The Tournament Fared Online](https://yomu.fyi/post/women-s-world-cup-2023-how-the-tournament-fared-online.md)
- Company: [Brandwatch](https://yomu.fyi/company/brandwatch.md)
- Author: Gemma Joyce
- Published: Aug 21, 2023
- Type: Explainer

The analysis examines online conversation around the 2023 FIFA Women’s World Cup using English-language mentions from social media, blogs, forums, and news sources collected between 20 July and 20 August 2023. It reports over 2.2 million social-media mentions, with major peaks during the Round of 16, the semi-finals, and the final, which generated more than 150,000 mentions and ended with Spain winning the title. Among gender-categorized authors on X, 75% were male, while England was the most discussed country, followed by Australia, the United States, New Zealand, and Spain. Mary Earps’s penalty save produced an initial final-minute spike, and Spain’s coronation prompted a peak of 2,100 mentions at 10:03 PM AEST. The analysis concludes that mention volume, sentiment, emotion, and team comparisons can help brands identify which aspects of the sport generate the most interest and where to participate.


[Newer posts](https://yomu.fyi/posts/page/191.md) · [Older posts](https://yomu.fyi/posts/page/193.md)