The DeepSeek API uses an API for­mat com­pat­i­ble with OpenAI/Anthropic. By mod­i­fy­ing the con­fig­u­ra­tion, you can use the OpenAI/Anthropic SDK or soft­wares com­pat­i­ble with the OpenAI/Anthropic API to ac­cess the DeepSeek API.

* The model names deepseek-chat and deepseek-rea­soner will be dep­re­cated on 2026/07/24. For com­pat­i­bil­ity, they cor­re­spond to the non-think­ing mode and think­ing mode of deepseek-v4-flash, re­spec­tively.

Invoke The Chat API​

Once you have ob­tained an API key, you can ac­cess the DeepSeek model us­ing the fol­low­ing ex­am­ple scripts in the OpenAI API for­mat. This is a non-stream ex­am­ple, you can set the stream pa­ra­me­ter to true to get stream re­sponse.

For ex­am­ples us­ing the Anthropic API for­mat, please re­fer to Anthropic API.

curl

python

nodejs

curl https://​api.deepseek.com/​chat/​com­ple­tions \ -H “Content-Type: ap­pli­ca­tion/​json” \ -H “Authorization: Bearer ${DEEPSEEK_API_KEY}” \ -d ‘{ “model”: “deepseek-v4-pro”, “messages”: [ {“role”: “system”, “content”: “You are a help­ful as­sis­tant.“}, {“role”: “user”, “content”: “Hello!“} ], “thinking”: {“type”: “enabled”}, “reasoning_effort”: “high”, “stream”: false }’

Please make sure your browser sup­ports JavaScript and cook­ies and that you are not block­ing them from load­ing. For more in­for­ma­tion you can re­view our Terms of Service and Cookie Policy.

First en­thu­si­asm

A cou­ple of weeks ago I sub­scribed to Claude Code, and dur­ing the first few weeks I had a re­ally nice ex­pe­ri­ence. It was fast, the to­ken al­lowance was fair, and the qual­ity was good.

I learned they had

raised the to­ken al­lowance for non-rush hours

, and since they op­posed some gov­ern­men­tal rules, it felt good to sup­port the right cause.

(づ ￣ ³￣)づ

However… for about three weeks now my ini­tial en­thu­si­asm has been rapidly wan­ing.

It be­gan with an is­sue three weeks ago. I started work­ing in the morn­ing af­ter about a ten-hour break; enough time for my to­kens to re­fresh.

I sent two small ques­tions to Claude Haiku. They were sim­ple ques­tions, not even re­lated to the repos­i­tory.

Suddenly, to­ken us­age spiked to 100%.

Have a nice break…

I con­tacted their “AI sup­port bot”, which re­turned some de­fault sup­port non­sense and did­n’t re­ally un­der­stand the prob­lem. So I asked for hu­man sup­port. A cou­ple of days later a - what ap­peared to be - hu­man sup­port per­son sent a re­ply. It be­gan like this:

“Our sys­tems are de­tect­ing your in­quiry is re­gard­ing us­age lim­its on your Pro or Max plan.”

Yeah, well — it’s the Pro plan. Seems like your sys­tems weren’t ac­tu­ally queried; it was just a de­fault in­tro and prob­a­bly a de­fault an­swer, be­cause:

This was fol­lowed by an ex­ten­sive what seems to be copy-and-paste an­swer from their docs ex­plain­ing how daily and weekly lim­its work.

And it closed with the typ­i­cally frus­trat­ing line, that no cus­tomer likes to read at the end of an e-mail and which is just the clas­si­cal mid­dle-fin­ger of cus­tomer sup­port - we don’t care if your prob­lem is solved or not, we de­clared it closed.

“Note that fur­ther replies to this ticket may not be mon­i­tored. If your re­quest is not re­gard­ing us­age lim­its on your Pro or Max plan, or you need ad­di­tional sup­port, please visit our help page at”

Great! Sending an au­to­mated e-mail that does not re­fer to the ac­tual prob­lem and then clos­ing the chan­nel. Thanks for noth­ing, I guess? Or was I wrong. I asked Claude Haiku:

@Haiku:

See the cus­tomer’s re­quest here and the re­sponse from the AI and later W***** - did they an­swer the con­cern/​ques­tion of the cus­tomer?

See the cus­tomer’s re­quest here and the re­sponse from the AI and later W***** - did they an­swer the con­cern/​ques­tion of the cus­tomer?

(╯°_°）╯︵ ┻━┻

Declining qual­ity

In the fol­low­ing days and weeks, the qual­ity was far from sat­is­fy­ing my needs or match­ing my ini­tial ex­pe­ri­ence. While I used to be able to work on up to three pro­jects at once, now the to­ken limit was ex­hausted af­ter two hours on a sin­gle pro­ject.

And the qual­ity was de­grad­ing. I am fully aware this is quite sub­jec­tive and that the qual­ity of the agent is al­ways heav­ily im­pacted by the op­er­a­tor. The fail­ure usu­ally ap­pears in front of the screen. But hey, I also de­velop us­ing Github’s Copilot, OpenAI’s Codex and I am run­ning my own in­fer­ence with OMLX and Continue us­ing Qwen3.5 – 9B. I’m not the ex­pert, I’m lazy some­times but I prob­a­bly know a thing or two.

Let me give you this won­der­ful ex­am­ple: yes­ter­day I asked Claude Opus to refac­tor a pro­ject.

While I was brows­ing the mod­el’s think­ing log - which I strongly sug­gest do­ing not only oc­ca­sion­ally - I found this:

Rather than edit­ing every slider in JSX, I’ll add a generic ini­tial­izer in ui-events.js that auto-in­jects value dis­plays for all range in­puts that lack one.

Rather than edit­ing every slider in JSX, I’ll add a generic ini­tial­izer in ui-events.js that auto-in­jects value dis­plays for all range in­puts that lack one.

This is clearly bad prac­tice. It’s a cheap workaround you would­n’t ex­pect even from a ju­nior dev; it reads like some­one who just does­n’t want to de­liver a good re­sult. My re­sponse:

“you can’t be se­ri­ous — is this how you fix things? just WORKAROUNDS????”

At least Opus ad­mit­ted:

“You’re right, that was lazy. Let me do it prop­erly — add the la­bels di­rectly in the JSX and wire them ex­plic­itly.”

Needless to say, this short­cut cost me around 50% of my five-hour to­ken al­lowance.

(ง •̀_•́)ง

And even more…

Now this cache topic comes up

-

among oth­ers

. at least they are talk­ing about it openly. The prob­lem was: when you get back to work af­ter some time, your con­ver­sa­tion cache is gone and the model starts read­ing your code­base again. Cost-wise this is smart. But ex­pe­ri­ence-wise? It means you paid to­kens for the ini­tial load and, af­ter a forced break be­cause the five-hour to­ken win­dow hit its limit, you pay again for the same load.

Think that’s all? Wait, I also got this funny anec­dote: all of a sud­den the weekly win­dow changed from to­day to Monday. OK, I was thank­ful be­cause it came with a re­set to zero. But still: what is go­ing on, Anthropic? Not only that — while I was work­ing on my pro­ject, watch­ing to­ken us­age with Argus-eyed vig­i­lance, this lit­tle warn­ing popped up:

Wait, what? I’m nei­ther part of an or­ga­ni­za­tion nor do I see any hint why I sud­denly have to worry about a “monthly us­age limit” — also the hourly and weekly lim­its were still not ex­ceeded. What is hap­pen­ing right now?

Turns out — two hours later - it al­lowed me to con­tinue work­ing. The warn­ing was gone.

At least

this doc­u­men­ta­tion

does not men­tion a monthly us­age limit. And the set­tings page only lists the lim­its for the cur­rent ses­sion and week.

So… what is this monthly limit all about, Anthropic?

Sorry to let you down, Anthropic

I am a huge fan of the prod­uct. Theoretically every­thing just works like a charm; it of­fers so many op­por­tu­ni­ties. I built my

A US spe­cial forces sol­dier in­volved in the cap­ture of Venezuelan President Nicolás Maduro was ar­rested and charged for al­legedly bet­ting on that op­er­a­tion, net­ting him $400,000 in prof­its.

According to an in­dict­ment un­sealed Thursday, Master Sgt. Gannon Ken Van Dyke opened an ac­count in late December on Polymarket, one of the best-known pre­dic­tion mar­kets. He wa­gered over $32,000 that Maduro would be “out” by January. The bet was a long-shot.

But Van Dyke was in­volved in the plan­ning and ex­e­cu­tion of Operation Absolute Resolve, pros­e­cu­tors al­lege, and had ac­cess to clas­si­fied in­for­ma­tion be­fore he placed the bet. His win­nings, though anony­mous, caught the at­ten­tion of law en­force­ment al­most im­me­di­ately.

Van Dyke, an ac­tive duty sol­dier sta­tioned at Fort Bragg, faces five crim­i­nal charges for steal­ing and mis­us­ing con­fi­den­tial gov­ern­ment in­for­ma­tion, theft and fraud.

He ap­peared in court in North Carolina on Friday and paid a $250,000 bond. He is set to be ar­raigned in New York City on Tuesday and also had to sur­ren­der his pass­port.

Van Dyke al­legedly made 13 bets from December 27 to January 2, the last be­ing hours be­fore the overnight cap­ture. Prosecutors said Van Dyke sent his more than $400,000 in prof­its to a for­eign cryp­tocur­rency vault be­fore he de­posited them in an on­line bro­ker­age ac­count.

A mas­ter sergeant in the Army is a se­nior non­com­mis­sioned of­fi­cer, con­sid­ered a key tac­ti­cal leader and tech­ni­cal ex­pert and serv­ing as the prin­ci­pal NCO typ­i­cally at the Army bat­tal­ion level. Senior NCOs are of­ten looked to for set­ting and up­hold­ing the stan­dard for more ju­nior sol­diers in the unit.

Video Ad Feedback

US spe­cial forces sol­dier ar­rested af­ter al­legedly win­ning $400,000 on Maduro raid

0:40

• Source:

CNN

US spe­cial forces sol­dier ar­rested af­ter al­legedly win­ning $400,000 on Maduro raid

0:40

“Those en­trusted to safe­guard our na­tion’s se­crets have a duty to pro­tect them and our armed ser­vice mem­bers, and not to use that in­for­ma­tion for per­sonal fi­nan­cial gain,” said Jay Clayton, US at­tor­ney for the Southern District of New York.

Van Dyke was pho­tographed just af­ter the op­er­a­tion — and from when he placed his fi­nal bet — on “what ap­pears to be the deck of a ship at sea, at sun­rise wear­ing U.S. mil­i­tary fa­tigues, and car­ry­ing a ri­fle, stand­ing along­side three other in­di­vid­u­als wear­ing U.S. mil­i­tary fa­tigues,” court doc­u­ments say.

Van Dyke prof­ited more than $400,000, pros­e­cu­tors say. He then al­legedly moved those win­nings to a for­eign cryp­tocur­rency vault be­fore he de­posited them in an on­line bro­ker­age ac­count in what pros­e­cu­tors called an at­tempt to con­ceal their ori­gin.

The Commodity Futures Trading Commission filed a re­lated com­plaint against Van Dyke on Thursday, seek­ing resti­tu­tion, dis­gorge­ment and civil mon­e­tary penal­ties.

CNN re­ported last month that fed­eral pros­e­cu­tors were in­ves­ti­gat­ing the Maduro trade, ac­cord­ing to a per­son fa­mil­iar with the mat­ter. The chiefs of the se­cu­ri­ties and com­mod­ity fraud unit at the US at­tor­ney’s of­fice in Manhattan met with rep­re­sen­ta­tives at Polymarket last month.

After the bets were placed, the US mil­i­tary launched a covert op­er­a­tion that ex­tra­dited Maduro from the pres­i­den­tial palace in Caracas in an overnight cap­ture while com­ing un­der heavy fire. Maduro was trans­ported to New York to face fed­eral drug-traf­fick­ing re­lated charges. He has pleaded not guilty.

Polymarket in a post on X said, “When we iden­ti­fied a user trad­ing on clas­si­fied gov­ern­ment in­for­ma­tion, we re­ferred the mat­ter to the DOJ & co­op­er­ated with their in­ves­ti­ga­tion. Insider trad­ing has no place on Polymarket. Today’s ar­rest is proof the sys­tem works.”

ABC News first re­ported Thursday’s ar­rest.

Trading on pre­dic­tion mar­kets has ex­ploded the past year, with users now spend­ing a few bil­lion dol­lars each week on such sites.

Lawmakers in Congress have in­tro­duced more than a dozen new bills this year to fur­ther reg­u­late pre­dic­tion mar­kets. Some of the bills, which gained bi­par­ti­san sup­port, would stiffen penal­ties against gov­ern­ment of­fi­cials who en­gage in in­sider trad­ing.

Trump told re­porters Thursday he is con­cerned about the grow­ing trend of bet­ting on geopo­lit­i­cal events. Asked about the charges against the US sol­dier, the pres­i­dent said he was not fa­mil­iar with the specifics of the in­ci­dent but com­pared it to base­bal­l’s all-time hit leader Pete Rose.

“That’s like Pete Rose bet­ting on his own team,” Trump said, re­fer­ring to the late base­ball player who was banned from base­ball for gam­bling.

Pressed on whether he is con­cerned about bet­ting tied to the war with Iran, Trump said it’s a global is­sue.

“Well I think that the whole world, un­for­tu­nately, has be­come some­what of a casino,” Trump said, adding that such bet­ting is hap­pen­ing “all over the world, and every place they’re do­ing these bet­ting things.”

“Now, I think that I’m not happy with it,” he con­cluded.

The Trump ad­min­is­tra­tion ap­proved Polymarket last year to start of­fer­ing trades for American cus­tomers, but its US-facing site is­n’t fully op­er­a­tional yet. The Maduro-related trades oc­curred on Polymarket’s highly pop­u­lar in­ter­na­tional site.

That site op­er­ates out of the reach of US reg­u­la­tions — which is how it’s able to of­fer mar­kets re­lated to war, which is il­le­gal un­der fed­eral law. But ex­perts say Americans can eas­ily ac­cess the off­shore site with a vir­tual pri­vate net­work, or VPN.

There is a de­bate in the pre­dic­tion mar­ket in­dus­try over the role of in­sid­ers in pre­dic­tion mar­kets. Some ex­perts see these mar­kets as a ve­hi­cle for in­for­ma­tion to flow more freely from in­sid­ers to the gen­eral pub­lic.

Asked about in­sider trad­ing risks, Polymarket’s CEO told Axios in November it was “super cool” that his plat­form “creates this fi­nan­cial in­cen­tive for peo­ple to go and di­vulge the in­for­ma­tion to the mar­ket,” in­clud­ing in­sid­ers.

Polymarket rolled out new rules in March, to “clarify three core cat­e­gories of pro­hib­ited in­sider trad­ing con­duct.”

They banned trades based on in­for­ma­tion that users were legally re­quired to keep con­fi­den­tial, and trades based on tips from some­one with the same oblig­a­tion. They also said peo­ple in “a po­si­tion of au­thor­ity or in­flu­ence” to af­fect the out­come of an event can­not par­tic­i­pate in any re­lated mar­kets.

This story has been up­dated fol­low­ing Van Dyke’s court ap­pear­ance on Friday.

CNN’s Marshall Cohen, Haley Britzky and Alejandria Jaramillo con­tributed to this re­port.

Please make sure your browser sup­ports JavaScript and cook­ies and that you are not block­ing them from load­ing. For more in­for­ma­tion you can re­view our Terms of Service and Cookie Policy.

Hi friends,

I’ll be at­tend­ing Babashka Conf on May 8 and Dutch Clojure Days on May 9.

If you’re at­tend­ing ei­ther (or just vis­it­ing Amsterdam), drop me a line!

When I have an idea for a pro­ject, it tends to go in one of these two di­rec­tions:

I just do it. Maybe I make a few mi­nor re­vi­sions, but of­ten it turns out ex­actly how I’d imag­ined and I’m happy.

I just do it. Maybe I make a few mi­nor re­vi­sions, but of­ten it turns out ex­actly how I’d imag­ined and I’m happy.

I think, “I should look for prior art”. There’s a lot of prior art, deal­ing with a much broader scope than I’d orig­i­nally imag­ined. I start to won­der if I should in­cor­po­rate that scope. Or per­haps try to build my thing on top of the ex­ist­ing sorta-nearby-so­lu­tions. Or maybe I should just use the pop­u­lar thing. Although I could do a bet­ter job than that thing, if I put a bunch of time into it. But ac­tu­ally, I don’t want to main­tain a big pop­u­lar pro­ject, nor do I want to put that much time into this pro­ject. Uh oh, now I’ve spent a bunch of time, hav­ing nei­ther ad­dressed the orig­i­nal is­sue nor ex­pe­ri­enced the joy of cre­at­ing some­thing.

I think, “I should look for prior art”. There’s a lot of prior art, deal­ing with a much broader scope than I’d orig­i­nally imag­ined. I start to won­der if I should in­cor­po­rate that scope. Or per­haps try to build my thing on top of the ex­ist­ing sorta-nearby-so­lu­tions. Or maybe I should just use the pop­u­lar thing. Although I could do a bet­ter job than that thing, if I put a bunch of time into it. But ac­tu­ally, I don’t want to main­tain a big pop­u­lar pro­ject, nor do I want to put that much time into this pro­ject. Uh oh, now I’ve spent a bunch of time, hav­ing nei­ther ad­dressed the orig­i­nal is­sue nor ex­pe­ri­enced the joy of cre­at­ing some­thing.

I pre­fer the first out­come, and I think the piv­otal fac­tor is how well I’ve in­ter­nal­ized my own suc­cess cri­te­ria.

For ex­am­ple, last week­end I hosted my friend Marcin and we de­cided it’d be fun to do some wood­work­ing, so we threw to­gether this shelf and 3d-printed hang­ers for my kitchen:

Absolute banger of a pro­ject:

brain­stormed the de­sign over cof­fee

did a few 3d-print it­er­a­tions for the Ikea bin hang­ers (OnShape CAD, if you want to print your own)

used ma­te­r­ial left­over from my work­bench

rounded the cor­ner by eye with a palm sander

sealed the raw ply­wood edge with some left­over paint from a friend

done in a week­end

The main suc­cess cri­te­ria was to jam on wood­work­ing with a friend, and that helped me not over­think the ob­ject-level suc­cess cri­te­ria: Just make a shelf for my ex­act kitchen!

In con­trast, this past Friday I no­ticed diff­tas­tic did a poor job, so I de­cided to shop around for struc­tural/​se­man­tic diff tools and re­lated work­flows (a topic I’ve never stud­ied, that I’m in­creas­ingly in­ter­ested in as I’m re­view­ing more and more LLM-generated code).

I spent 4 hours over the week­end re­search­ing ex­ist­ing tools (see my notes be­low), go­ing through dark pe­ri­ods of both “semantic tree diff­ing is a PhD-level com­plex prob­lem” and “why do all of these have MCP servers? I don’t want an MCP server”, be­fore I came to my senses and re­mem­bered my orig­i­nal suc­cess cri­te­ria: I just want a nicer diff­ing work­flow for my­self in Emacs, I should just build it my­self — should take about 4 hours.

I’m cau­tiously op­ti­mistic that, hav­ing had this re­al­iza­tion and com­mit­ting my­self to a min­i­mal scope, I’ll be able to knock out a pro­to­type be­fore run­ning out of mo­ti­va­tion.

However, other long-run­ning in­ter­ests of mine:

in­ter­faces for pro­to­typ­ing hard­ware (discussed September 2023)

a pro­gram­ming lan­guage that fuses what I like about Clojure and Rust (November 2023)

a pro­gram­ming lan­guage for CAD (constraints, bidi­rec­tional edit­ing, other du­bi­ous ideas)

seem to be deep in the well of out­come #2.

That is, I’ve spent hun­dreds of hours on back­ground re­search and lit­tle pro­to­types, but haven’t yet syn­the­sized any­thing that ad­dresses the orig­i­nal mo­ti­vat­ing is­sue.

It’s not quite that I re­gret that time — I do love learn­ing by read­ing — but I have a nag­ging sense of un­ease that my in­ner critic (fear of fail­ure?) is si­lenc­ing my gen­er­a­tive ten­den­cies, keep­ing me from the much more en­joy­able (and pro­duc­tive!) learn­ing by do­ing.

I think in these cases the suc­cess cri­te­ria has been much fuzzier: Am I try­ing to re­place my own us­age of Rust/Clojure?

Only for some sub­set of prob­lems?

Or is it that I ac­tu­ally just need a play­ground to learn about lan­guage de­sign/​im­ple­men­ta­tion, and it’s fine if I don’t end up us­ing it?

Ditto for CAD: Am I try­ing to re­place my com­mer­cial CAD tool in fa­vor of my own?

Only for some sub­set of sim­ple or par­tic­u­larly para­met­ric parts?

Do I care if it’s use­ful for oth­ers?

Does my tool need to be leg­i­bly dif­fer­ent from ex­ist­ing open-source tools?

It’s worth con­sid­er­ing these ques­tions, sure.

But at the end of the day, I’d much rather have done a lot than have only con­sid­ered a lot.

So I’m try­ing to em­brace my in­ner clue­less 20-year-old and just do things — even if some turn out to be “obviously bad” in hind­sight, I’ll still be com­ing out ahead on net =D

Conservation of scope creep

Of course, there’s only so much time to “just do things”, and there’s a bal­ance to be had. I’m not sure how many times I’ll re-learn YAGNI (“you ain’t gonna need it”) in my ca­reer, but I was re­minded of it again af­ter writ­ing a bunch of code with an LLM agent, then even­tu­ally com­ing to my senses and throw­ing it all out.

I wanted a Finda-style filesys­tem-wide fuzzy path search for Emacs.

Since I’ve built (by hand, typ­ing the code my­self!) this ex­act func­tion­al­ity be­fore (walk filesys­tem to col­lect paths, in­dex them by tri­gram, do fast fuzzy queries via bitmap in­ter­sec­tions), I fig­ured it’d only take a few hours to su­per­vise an LLM to write all the code.

I started with a “plan mode” chat, and the LLM sug­gested a li­brary, Nucleo, which turned up since I wrote Finda (10 years ago, eek!).

I read through it, found it quite well-de­signed and doc­u­mented, and de­cided to use it so I’d get its smart case and Unicode nor­mal­iza­tion func­tion­al­ity.

(E.g., query foo matches Foo and foo, whereas query Foo won’t match foo; sim­i­larly for cafe and café.)

Finding a great li­brary was­n’t the prob­lem, the prob­lem was that Nucleo also sup­ported some ex­tra func­tion­al­ity: an­chors (^foo only matches at the be­gin­ning of a line).

This got me think­ing about what that might mean in a cor­pus that con­sists en­tirely of file paths.

Anchoring to the be­gin­ning of a line is­n’t use­ful (everything starts with /), so I de­cided to try and in­ter­pret the an­chors with re­spect to the path seg­ments.

E.g., ^foo would match /root/foobar/ but not /root/barfoo/.

But to do this ef­fi­ciently, the in­dex needs to keep track of seg­ment bound­aries so that the query can be checked against each seg­ment quickly.

But then we also need to han­dle a slash oc­cur­ring in an an­chored query (e.g., ^foo/bar) since that would­n’t get matched when only look­ing at seg­ments in­di­vid­u­ally (root, foo, bar, and baz of a match­ing path /root/foo/bar/baz/).

Working through this took sev­eral hours: first throw­ing around de­sign ideas with an LLM, hav­ing it write code to wrap Nucleo’s types, then re­al­iz­ing its code was bloated and did­n’t spark joy, so fi­nally writ­ing my own (smaller) wrap­per.

Then, af­ter a break, I re­al­ized:

I can’t think of a sit­u­a­tion where I’d ever wished Finda had an­chor func­tion­al­ity

In a cor­pus of paths, I can an­chor by just adding / to the start or end of a query (this works for every­thing ex­cept an­chor­ing to the end of a file­name).

So I tossed all of the an­chor­ing code.

I’m pretty sure I still came out ahead com­pared to if I’d tried to write every­thing my­self sans LLM or dis­cus­sion with oth­ers, but I’m not cer­tain.

Perhaps there’s some kind of con­ser­va­tion law here: Any in­creases in pro­gram­ming speed will be off­set by a cor­re­spond­ing in­crease in un­nec­es­sary fea­tures, rab­bit holes, and di­ver­sions.

Structural diff­ing

Speaking of un­nec­es­sary di­ver­sions, let me tell you every­thing I’ve learned about struc­tural diff­ing re­cently — if you have thoughts/​feel­ings/​ref­er­ences in this space, I’d love to hear about ’em!

When we’re talk­ing about code, a “diff” usu­ally means a sum­mary of the line-by-line changes be­tween two ver­sions of a file.

This might be ren­dered as a “unified” view, where changed lines are pre­fixed with + or - to in­di­cate whether they’re ad­di­tions or dele­tions.

For ex­am­ple:

We’ve re­moved cof­fee and added ap­ple.

The same diff might also be ren­dered in a side-by-side view, which can be eas­ier to read when there are more com­plex changes:

The prob­lem with these line-by-line diffs is that they’re not aware of higher-level struc­ture like func­tions, types, etc. — if some braces match up some­how be­tween ver­sions, they might not be shown at all, even if the braces “belong” to dif­fer­ent func­tions.

There’s a won­der­ful tool, diff­tas­tic, which tries to ad­dress this by cal­cu­lat­ing diffs us­ing treesit­ter-pro­vided con­crete syn­tax trees.

It’s a huge im­prove­ment over line-based diffs, but un­for­tu­nately it does­n’t al­ways do a great job match­ing en­ti­ties be­tween ver­sions.

Here’s the diff that mo­ti­vated this en­tire foray:

Note that it does­n’t match up struct PendingClick, it shows it deleted on the left and added on the right.

I haven’t dug into why diff­tas­tic fails to match here, but I do feel like it’s wrong — even if the over­all diff would be longer, I’d still rather see PendingClickRequest and PendingClick matched up be­tween both sides.

Here’s a sum­mary of tools / ref­er­ences in the space:

The most “baked” and thought­ful se­man­tic diff tool I found is, per­haps un­sur­pris­ingly, se­man­ticd­iff.com, a small German com­pany with a free VSCode plu­gin and web app that shows diffs for github PRs. Unfortunately they don’t have any code li­braries I can use as a foun­da­tion for the work­flow I want.

this se­man­ticd­iff vs. diff­tas­tic blog post cov­ers a lot of great de­tails (including that diff­tas­tic does­n’t even show se­man­ti­cally mean­ing­ful in­den­ta­tion changes in python !!!)

one of the au­thors has great HN com­ments with hard-won back­ground knowl­edge. E.g., they moved away from treesit­ter be­cause it’s un­re­li­able for se­man­tics:

Context-sensitive key­words in par­tic­u­lar were a con­stant source of an­noy­ance. The gram­mar looks cor­rect, but it will fail to parse be­cause of the way the lexer works. You don’t want your tool to abort just be­cause some­one named their pa­ra­me­ter “async”.

The most “baked” and thought­ful se­man­tic diff tool I found is, per­haps un­sur­pris­ingly, se­man­ticd­iff.com, a small German com­pany with a free VSCode plu­gin and web app that shows diffs for github PRs. Unfortunately they don’t have any code li­braries I can use as a foun­da­tion for the work­flow I want.

this se­man­ticd­iff vs. diff­tas­tic blog post cov­ers a lot of great de­tails (including that diff­tas­tic does­n’t even show se­man­ti­cally mean­ing­ful in­den­ta­tion changes in python !!!)

one of the au­thors has great HN com­ments with hard-won back­ground knowl­edge. E.g., they moved away from treesit­ter be­cause it’s un­re­li­able for se­man­tics:

Context-sensitive key­words in par­tic­u­lar were a con­stant source of an­noy­ance. The gram­mar looks cor­rect, but it will fail to parse be­cause of the way the lexer works. You don’t want your tool to abort just be­cause some­one named their pa­ra­me­ter “async”.

Context-sensitive key­words in par­tic­u­lar were a con­stant source of an­noy­ance. The gram­mar looks cor­rect, but it will fail to parse be­cause of the way the lexer works. You don’t want your tool to abort just be­cause some­one named their pa­ra­me­ter “async”.

diff­sit­ter

built on treesit­ter, has MCP server. README in­cludes list of sim­i­lar pro­jects.

lots of github stars, but does­n’t seem par­tic­u­larly well-doc­u­mented; I could­n’t find an ex­pla­na­tion of how it works, but the diff­tas­tic wiki says it “runs longest-com­mon-sub­se­quence on the leaves of the tree”

diff­sit­ter

built on treesit­ter, has MCP server. README in­cludes list of sim­i­lar pro­jects.

lots of github stars, but does­n’t seem par­tic­u­larly well-doc­u­mented; I could­n’t find an ex­pla­na­tion of how it works, but the diff­tas­tic wiki says it “runs longest-com­mon-sub­se­quence on the leaves of the tree”

gumtree

re­search / aca­d­e­mic ori­gin in 2014

re­quires Java, so no-go for my use case of a quick tool I can use via Emacs

gumtree

re­search / aca­d­e­mic ori­gin in 2014

re­quires Java, so no-go for my use case of a quick tool I can use via Emacs

mer­gi­raf: treesit­ter-based merge-dri­ver writ­ten in rust

very nice ar­chi­tec­ture overview; tool uses Gumtree al­go­rithm

docs and adorable il­lus­tra­tions in­di­cate this pro­ject was clearly writ­ten by a thought­ful hu­man

se­man­ticd­iff.com au­thor in HN com­ments:

> GumTree is good at re­turn­ing a re­sult quickly, but there are quite a few cases where it al­ways re­turned bad matches for us, no mat­ter how many fol­low-up pa­pers with im­prove­ments we tried to im­ple­ment. In the end we switched over to a dijk­stra based ap­proach that tries to min­i­mize the cost of the map­ping

mer­gi­raf: treesit­ter-based merge-dri­ver writ­ten in rust

very nice ar­chi­tec­ture overview; tool uses Gumtree al­go­rithm

Spinel — Ruby AOT Compiler

Spinel com­piles Ruby source code into stand­alone na­tive ex­e­cuta­bles.

It per­forms whole-pro­gram type in­fer­ence and gen­er­ates op­ti­mized C code,

achiev­ing sig­nif­i­cant speedups over CRuby.

Spinel is self-host­ing: the com­piler back­end is writ­ten in Ruby and

com­piles it­self into a na­tive bi­nary.

How It Works

Ruby (.rb)

|

v

spinel_­parse Parse with Prism (libprism), se­ri­al­ize AST

| (C bi­nary, or CRuby + Prism gem as fall­back)

v

AST text file

|

v

spinel_­code­gen Type in­fer­ence + C code gen­er­a­tion

| (self-hosted na­tive bi­nary)

v

C source (.c)

|

v

cc -O2 -Ilib -lm Standard C com­piler + run­time header

|

v

Native bi­nary Standalone, no run­time de­pen­den­cies

Quick Start

# Fetch libprism sources (from the prism gem on rubygems.org):

make deps

# Build every­thing:

make

# Write a Ruby pro­gram:

cat > hello.rb <<‘RUBY’

def fib(n)

if n < 2

n

else

fib(n - 1) + fib(n - 2)

end

end

puts fib(34)

RUBY

# Compile and run:

./spinel hello.rb

./hello # prints 5702887 (instantly)

Options

./spinel app.rb # com­piles to ./app

./spinel app.rb -o myapp # com­piles to ./myapp

./spinel app.rb -c # gen­er­ates app.c only

./spinel app.rb -S # prints C to std­out

Self-Hosting

Spinel com­piles its own back­end. The boot­strap chain:

CRuby + spinel_­parse.rb → AST

CRuby + spinel_­code­gen.rb → gen1.c → bin1

bin1 + AST → gen2.c → bin2

bin2 + AST → gen3.c

gen2.c == gen3.c (bootstrap loop closed)

Benchmarks

74 tests pass. 55 bench­marks pass.

Geometric mean: ~11.6x faster than miniruby (Ruby 4.1.0dev) across

the 28 bench­marks be­low. Baseline is the lat­est CRuby miniruby build

(without bun­dled gems), which is con­sid­er­ably faster than the sys­tem

ruby (3.2.3); Spinel’s ad­van­tage is cor­re­spond­ingly smaller but still

sub­stan­tial on com­pu­ta­tion-heavy work­loads.

Computation

Data Structures & GC

Real-World Programs

Supported Ruby Features

Core: Classes, in­her­i­tance, su­per, in­clude (mixin), at­tr_ac­ces­sor,

Struct.new, alias, mod­ule con­stants, open classes for built-in types.

Control Flow: if/​el­sif/​else, un­less, case/​when,

case/​in (pattern match­ing), while, un­til, loop, for..in

(range and ar­ray), break, next, re­turn, catch/​throw,

&. (safe nav­i­ga­tion).

Blocks: yield, block­_­given?, &block, proc {}, Proc.new,

lambda -> x { }, method(:name). Block meth­ods: each,

each_with­_in­dex, map, se­lect, re­ject, re­duce, sort_by,

any?, all?, none?, times, upto, downto.

Exceptions: be­gin/​res­cue/​en­sure/​retry, raise,

cus­tom ex­cep­tion classes.

Types: Integer, Float, String (immutable + mu­ta­ble), Array, Hash,

Range, Time, StringIO, File, Regexp, Bigint (auto-promoted), Fiber.

Polymorphic val­ues via tagged unions. Nullable ob­ject types (T?)

for self-ref­er­en­tial data struc­tures (linked lists, trees).

Global Variables: $name com­piled to sta­tic C vari­ables with

type-mis­match de­tec­tion at com­pile time.

Strings: << au­to­mat­i­cally pro­motes to mu­ta­ble strings (sp_String)

for O(n) in-place ap­pend. +, in­ter­po­la­tion, tr, ljust/​rjust/​cen­ter,

and all stan­dard meth­ods work on both. Character com­par­isons like

s[i] == “c” are op­ti­mized to di­rect char ar­ray ac­cess (zero al­lo­ca­tion).

Chained con­cate­na­tion (a + b + c + d) col­lapses to a sin­gle mal­loc

via sp_str_­con­cat4 / sp_str_­con­cat_arr — N-1 fewer al­lo­ca­tions.

Loop-local str.split(sep) reuses the same sp_S­trAr­ray across

it­er­a­tions (csv_process: 4 M al­lo­ca­tions elim­i­nated).

Regexp: Built-in NFA reg­exp en­gine (no ex­ter­nal de­pen­dency).

=~, $1-$9, match?, gsub(/​re/, str), sub(/​re/, str),

scan(/​re/), split(/​re/).

Bigint: Arbitrary pre­ci­sion in­te­gers via mruby-big­int. Auto-promoted

from loop mul­ti­pli­ca­tion pat­terns (e.g. q = q * k). Linked as sta­tic

li­brary — only in­cluded when used.

Ubuntu 26.04 (“Resolute Raccoon”) LTS has been re­leased

on sched­ule.

This re­lease brings a sig­nif­i­cant up­lift in se­cu­rity, per­for­mance,

and us­abil­ity across desk­top, server, and cloud en­vi­ron­ments. Ubuntu

26.04 LTS in­tro­duces TPM-backed full-disk en­cryp­tion, ex­panded use of

mem­ory-safe com­po­nents, im­proved ap­pli­ca­tion per­mis­sion con­trols, and

Livepatch sup­port for Arm sys­tems, help­ing re­duce down­time and

strengthen sys­tem re­silience. […]

The newest Edubuntu, Kubuntu, Lubuntu, Ubuntu Budgie, Ubuntu Cinnamon,

Ubuntu Kylin, Ubuntu Studio, Ubuntu Unity, and Xubuntu are also be­ing

re­leased to­day. For more de­tails on these, read their in­di­vid­ual re­lease

notes un­der the Official fla­vors sec­tion:

https://​doc­u­men­ta­tion.ubuntu.com/​re­lease-notes/​26.04/#​of­fi­cial-fla­vors

Maintenance up­dates will be pro­vided for 5 years for Ubuntu Desktop, Ubuntu

Server, Ubuntu Cloud, Ubuntu WSL, and Ubuntu Core. All the re­main­ing fla­vors

will be sup­ported for 3 years.

This re­lease brings a sig­nif­i­cant up­lift in se­cu­rity, per­for­mance,

and us­abil­ity across desk­top, server, and cloud en­vi­ron­ments. Ubuntu

26.04 LTS in­tro­duces TPM-backed full-disk en­cryp­tion, ex­panded use of

mem­ory-safe com­po­nents, im­proved ap­pli­ca­tion per­mis­sion con­trols, and

Livepatch sup­port for Arm sys­tems, help­ing re­duce down­time and

strengthen sys­tem re­silience. […]

The newest Edubuntu, Kubuntu, Lubuntu, Ubuntu Budgie, Ubuntu Cinnamon,

Ubuntu Kylin, Ubuntu Studio, Ubuntu Unity, and Xubuntu are also be­ing

re­leased to­day. For more de­tails on these, read their in­di­vid­ual re­lease

notes un­der the Official fla­vors sec­tion:

https://​doc­u­men­ta­tion.ubuntu.com/​re­lease-notes/​26.04/#​of­fi­cial-fla­vors

Maintenance up­dates will be pro­vided for 5 years for Ubuntu Desktop, Ubuntu

Server, Ubuntu Cloud, Ubuntu WSL, and Ubuntu Core. All the re­main­ing fla­vors

will be sup­ported for 3 years.

See the re­lease

notes for a list of changes, sys­tem re­quire­ments, and more.

Please make sure your browser sup­ports JavaScript and cook­ies and that you are not block­ing them from load­ing. For more in­for­ma­tion you can re­view our Terms of Service and Cookie Policy.