--- schema: 1 type: video title: 'The Era of Compound Engineering — Kieran Klaassen, Every/Cora' description: >- He has not written a line of code this year, and has not read most of it either, yet he ships a full email client that thousands of people trust with their inbox. Kieran Klaassen has been rebuilding Cora alone since January, and the useful part of his account is the sequence of bottlenecks he moved through. Two years ago the code itself was bad, so he layered on review and skills until it got good. Then the plans were the constraint, until those got good too. Then knowing what to build at all. What was left after that was him repeating himself, which is what a memory system exists to fix. That is where compound engineering came from, and the rule attached to it is the demanding one. Spend half your time building the feature and the other half teaching the system whatever it got wrong. His counterintuitive claim is that this ends up cheaper in tokens rather than more expensive, because a stored solution means no correction pass and no research detour the next time around. The loop puts the human at both ends, brain on to decide what the problem actually is, then brain on again at the finish to raise the bar rather than to run QA, with hours of autonomous work in between. The bar he holds it to is that the next feature should be easier to build because this one shipped, which inverts the way complexity normally accumulates. Speaker info: - https://x.com/kieranklaassen - https://www.linkedin.com/in/kieran-klaassen/ - https://cora.computer Timestamps: 0:00 - Shipping without writing or reading the code 2:52 - Building an email client alone, on purpose 4:40 - The bottleneck moved from code to plans to judgment 5:30 - Where compound engineering came from 6:25 - The loop, and the human at both ends 8:10 - Half your time teaching the system what it got wrong 9:03 - Why stored solutions are cheaper in tokens 9:55 - The plugin, and building it while building the product 10:45 - Turning a backlog into an argued set of ideas 12:26 - Sharp questions on a document, and only enough of them 15:01 - The overnight loop, and polish as raising the bar 17:33 - Doing this without the plugin 19:14 - The next feature should be easier than this one --- Watch along with the corrected transcript, summary, timestamps and resources on this talk's official AIE page: https://ai.engineer/talks/_ehJyfHg1Vk-the-era-of-compound-engineering Join our upcoming AI Engineer conferences (see https://ai.engineer landing page): - AIEi Shanghai, November 5–6 — the first for meeting top Chinese labs and engineers - AIE CODE in SF, November 10–12 — the top AI Coding conference returns - AIEi Sydney, December 7–8 — the first AIEi run alongside NeurIPS 2026 in Sydney --- canonical: >- https://liquidgold.cc/channel/aidotengineer/explore/video/the-era-of-compound-engineering-kieran-klaassen-eve-e29c0ec1615e markdown: >- https://liquidgold.cc/channel/aidotengineer/video/the-era-of-compound-engineering-kieran-klaassen-eve-e29c0ec1615e.md llms: null parent: 'https://liquidgold.cc/channel/aidotengineer.md' channel: aidotengineer updated: '2026-10-24T05:01:52.050Z' language: null children: [] videoId: _ehJyfHg1Vk durationSeconds: 1238 publishedAt: '2026-08-20T15:00:06.000Z' searchChunks: - ordinal: 0 text: null startSeconds: 24 endSeconds: 175 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=24' heldReason: rights - ordinal: 1 text: null startSeconds: 186 endSeconds: 288 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=186' heldReason: rights - ordinal: 2 text: null startSeconds: 186 endSeconds: 288 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=186' heldReason: rights - ordinal: 3 text: null startSeconds: 299 endSeconds: 330 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=299' heldReason: rights - ordinal: 4 text: null startSeconds: 340 endSeconds: 387 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=340' heldReason: rights - ordinal: 5 text: null startSeconds: 398 endSeconds: 495 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=398' heldReason: rights - ordinal: 6 text: null startSeconds: 495 endSeconds: 507 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=495' heldReason: rights - ordinal: 7 text: null startSeconds: 507 endSeconds: 550 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=507' heldReason: rights - ordinal: 8 text: null startSeconds: 563 endSeconds: 601 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=563' heldReason: rights - ordinal: 9 text: null startSeconds: 655 endSeconds: 752 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=655' heldReason: rights - ordinal: 10 text: null startSeconds: 752 endSeconds: 763 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=752' heldReason: rights - ordinal: 11 text: null startSeconds: 763 endSeconds: 901 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=763' heldReason: rights - ordinal: 12 text: null startSeconds: 763 endSeconds: 901 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=763' heldReason: rights - ordinal: 13 text: null startSeconds: 913 endSeconds: 1060 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=913' heldReason: rights - ordinal: 14 text: null startSeconds: 913 endSeconds: 1060 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=913' heldReason: rights - ordinal: 15 text: null startSeconds: 1070 endSeconds: 1161 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=1070' heldReason: rights - ordinal: 16 text: null startSeconds: 1171 endSeconds: 1238 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=1171' heldReason: rights - ordinal: 17 text: null startSeconds: 1171 endSeconds: 1238 watch: 'https://liquidgold.cc/watch/_ehJyfHg1Vk?t=1171' heldReason: rights --- # The Era of Compound Engineering — Kieran Klaassen, Every/Cora He has not written a line of code this year, and has not read most of it either, yet he ships a full email client that thousands of people trust with their inbox. Kieran Klaassen has been rebuilding Cora alone since January, and the useful part of his account is the sequence of bottlenecks he moved through. Two years ago the code itself was bad, so he layered on review and skills until it got good. Then the plans were the constraint, until those got good too. Then knowing what to build at all. What was left after that was him repeating himself, which is what a memory system exists to fix. That is where compound engineering came from, and the rule attached to it is the demanding one. Spend half your time building the feature and the other half teaching the system whatever it got wrong. His counterintuitive claim is that this ends up cheaper in tokens rather than more expensive, because a stored solution means no correction pass and no research detour the next time around. The loop puts the human at both ends, brain on to decide what the problem actually is, then brain on again at the finish to raise the bar rather than to run QA, with hours of autonomous work in between. The bar he holds it to is that the next feature should be easier to build because this one shipped, which inverts the way complexity normally accumulates. Speaker info: - https://x.com/kieranklaassen - https://www.linkedin.com/in/kieran-klaassen/ - https://cora.computer Timestamps: 0:00 - Shipping without writing or reading the code 2:52 - Building an email client alone, on purpose 4:40 - The bottleneck moved from code to plans to judgment 5:30 - Where compound engineering came from 6:25 - The loop, and the human at both ends 8:10 - Half your time teaching the system what it got wrong 9:03 - Why stored solutions are cheaper in tokens 9:55 - The plugin, and building it while building the product 10:45 - Turning a backlog into an argued set of ideas 12:26 - Sharp questions on a document, and only enough of them 15:01 - The overnight loop, and polish as raising the bar 17:33 - Doing this without the plugin 19:14 - The next feature should be easier than this one --- Watch along with the corrected transcript, summary, timestamps and resources on this talk's official AIE page: https://ai.engineer/talks/\_ehJyfHg1Vk-the-era-of-compound-engineering Join our upcoming AI Engineer conferences (see https://ai.engineer landing page): - AIEi Shanghai, November 5–6 — the first for meeting top Chinese labs and engineers - AIE CODE in SF, November 10–12 — the top AI Coding conference returns - AIEi Sydney, December 7–8 — the first AIEi run alongside NeurIPS 2026 in Sydney --- Canonical: https://liquidgold.cc/channel/aidotengineer/explore/video/the-era-of-compound-engineering-kieran-klaassen-eve-e29c0ec1615e · Channel: [AI Engineer](https://liquidgold.cc/channel/aidotengineer.md) > Search chunk text is held until public-source provenance is verified. ## Document chunks > Missing: no stored document chunks are available.