OpenAI releases GPT-5.5 and GPT-5.5 Pro in the API

(developers.openai.com)

136 points | by arabicalories 2 hours ago

17 comments

  • guilamu 40 minutes ago
    Just tested it on my homemade Wordpress+GravityForms benchmark and it's one of the worst model of the leaderboard performance wise and the worst value wise: https://github.com/guilamu/llms-wordpress-plugin-benchmark

    I know it's only on a single benchmark, but I dont understand how it can be so bad...

    • goldenarm 18 minutes ago
      gemma4-e4b is 50% better than gemma4-26b in your benchmark, something's wrong
      • guilamu 15 minutes ago
        Yes those two models were tested on my own PC (local inference using my own CPU/GPU). So something my be bugged on my setup. gemma4-26b should be far better than gemma4-e4b.
    • DrProtic 18 minutes ago
      Seems like benchmark for how good a model is for vibe coding.

      Your prompt is extremely slim yet you score it on a bunch of features.

    • mosselman 27 minutes ago
      You even traveled in time to deliver us this benchmark.

      I really like this benchmarking. Have you evaluated the judge benchmark somehow? I'd love to setup my own similar benchmark.

      • guilamu 19 minutes ago
        Haha, just fixed the date!

        I haven't evaluated the judge benchmark. You have everything needed in the repo to do so though, so be my guest. It took me a bit of time to put all this together and won't have much more time to dedicate to it before a couple of weeks.

        BTW, if you explore the repo, sorry for all the French files...

    • ac29 30 minutes ago
      Your benchmark has Opus 4.7 performing significantly worse than Sonnet 4.6. Even if true on your benchmark, that is not representative of the overall performance of the models.
      • guilamu 22 minutes ago
        Yes Opus 4.7 fast (no reasoning) did a worst job than Sonnet 4.6 high (with reasoning) according to Gemini 3.1 Pro evaluation.
        • ac29 12 minutes ago
          Your table doesn't indicate reasoning vs non-reasoning, or reasoning level
          • guilamu 9 minutes ago
            When nothing is noted it's max reasoning (xhigh in copilot chat in vscode if available).

            The models not availble on copilot were tested through opencode (max reasoning) and deepseek v4 was tested through Cline (with max reasoning too).

  • wincy 1 hour ago
    Just tried it out for a prod issue was experiencing. Claude never does this sort of thing, I had it write an update statement after doing some troubleshooting, and I said “okay let’s write this in a transaction with a rollback” and GPT-5.5 gave me the old “okay,

    BEGIN TRAN;

    -- put the query here

    commit;

    I feel like I haven’t had to prod a model to actually do what I told it to in awhile so that was a shock. I guess that it does use fewer tokens that way, just annoying when I’m paying for the “cutting edge” model to have it be lazy on me like that.

    This is in Cursor the model popped up and so I tried it out from the model selector.

    • XCSme 48 minutes ago
      I feel like the last 2-3 generations of models (after gpt-5.3-codex) didn't really improve much, just changed stuff around and making different tradeoffs.
      • pixel_popping 45 minutes ago
        I disagree, it improved enormously especially at staying consistent for long-tasks, I have a task running for 32 days (400M+ tokens) via Codex and that's only since gpt-5.4
        • ericpauley 43 minutes ago
          Has that task accomplished anything yet?
          • codemog 34 minutes ago
            I think the OP is in for a rude surprise when the task is “finished”.
          • xp84 38 minutes ago
            Too soon to tell, give it a billion tokens before we make up our minds
            • pixel_popping 26 minutes ago
              Oh boy, you are far from what it requires, we are probably talking 3B+, but note that this is just codex, obviously codex is also doing automatic adversarial with the regular zoo (gemini-3.1-pro-preview, opus-4.6/4.7, gpt-5.3-codex, minimax-2.7, glm-5.1, mimo-2 (now 2.5) and so-on, you get the gist) :)
              • fl4regun 10 minutes ago
                what is that task doing???
          • SecretDreams 29 minutes ago
            Kept the OP employed for a full extra month at their high AI metric firm, hopefully.
        • lowdude 24 minutes ago
          That’s actually crazy, what kind of task is that? And is that a recurring kind of task like some analysis, or coding related?
          • pixel_popping 2 minutes ago
            Coding (along with docs, tests obviously), rewriting a huge chunk of the KVM hypervisor (in Kernel 7, started in the -rc2) and KSM and other modules, can't say too much about it yet (might do an announcement in coming weeks). The coding is automated but the plan took days of manual arguing (with all models possible) prior (while doing other things during waiting times as I currently manage 70 repos for an upcoming release of our Beta).

            I think users really underestimate the capabilities of "AI" when using the right tooling/combinations of models and procedures, that's talking with 2 decades of dev behind me, genuinely I'm not on phase with people saying it produces slop of any kind, at this stage, it's mostly the fault of the prompter (or the prompter not having enough tokens to do mass adversarial), but clearly, I can genuinely state that the code produced is overall the SAME quality as I would by being extremely meticulous.

            I'm like a bot following 30+ threads concurrently, sometimes it's fun, sometimes it feels like playing casino, sometimes it's boring, but this is truly an insane era if you have the funding for it, obviously we stack many MANY accounts in rotation 24/7, equivalent in API cost by myself is about 100K$+ which is only in a fraction of that cost thanks to the plans.

        • r_lee 21 minutes ago
          ...what? what kind of a task are you running?
    • endymi0n 22 minutes ago
      OpenAI is the first company that has reached a level of intelligence so high, the model has finally become smart enough to make YOU do all the work. Emergent behavior in action.

      All earnesty aside, OpenAI’s oddly specific singular focus on “intelligence per token” (also in the benchmarks) that literally noone else pushes so hard eerily reminds me of Apple’s Macbook anorexia era pre-M1. One metric to chase at the cost of literally anything else. GPT-5.3+ are some of the smartest models out there and could be a pleasure to work with, if they weren’t lazy bastards to the point of being completely infuriating.

    • hbn 21 minutes ago
      GPT-5.5 shatters benchmarks for amount of faith it puts in the user.
    • syspec 49 minutes ago
      Can't tell if above is good or bad.
  • QuadrupleA 6 minutes ago
    Exactly double the cost of GPT 5.4 - $5 per MTok input, $0.50 cached, $30 output.

    All the AI players definitely seem to be trying to claw more money out of their users at the moment.

  • ftonon 39 minutes ago
    Looks like the default config in the chat is instant 5.3, it only uses the 5.5 on the thinking variant
    • bnm04 19 minutes ago
      They moved a few months ago to have separate instant and thinking models. 5.3 is the latest instant, and 5.5 is a reasoning model.
  • neosat 1 hour ago
    Enterprise user here and still seeing only 5.4. Yesterday's announcement said that it will take a few hours to roll out to everybody. OpenAI needs better GTM to set the right expectations.
    • neosat 1 hour ago
      Just refreshed and see 5.5 now - yay! Love the speedy resolution ;) Thanks folks, I'll complain faster next time....
  • sigmoid10 1 hour ago
    Huh. Yesterday they said:

    >API deployments require different safeguards and we are working closely with partners and customers on the safety and security requirements for serving it at scale.

    And now this. I guess one day counts as "very soon." But I wonder what that meant for these safeguards and security requirements.

    • FINDarkside 1 hour ago
      When stuff is delayed due to "safeguards" it just means they don't think they have the compute to release it right now.
    • simonw 1 hour ago
      I wonder if the fact that GPT-5.5 was already available in their Codex-specific API which they had explicitly told people they were allowed to use for other purposes - https://simonwillison.net/2026/Apr/23/gpt-5-5/#the-openclaw-... - accelerated this release!
    • embedding-shape 1 hour ago
      The same person who've mercilessly lied about safety is still running the company, so not sure why anyone would expect any different from them moving forward. Previous example:

      > In 2023, the company was preparing to release its GPT-4 Turbo model. As Sutskever details in the memos, Altman apparently told Murati that the model didn’t need safety approval, citing the company’s general counsel, Jason Kwon. But when she asked Kwon, over Slack, he replied, “ugh . . . confused where sam got that impression.”

      Lots of cases where Altman hass not been entirely forthcoming about how important (or not) safety is for OpenAI. https://www.newyorker.com/magazine/2026/04/13/sam-altman-may... (https://archive.is/a2vqW)

  • czk 1 hour ago
    API page lists the knowledge cutoff as Dec 01, 2025 but when prompting the model it says June 2024.

       Knowledge cutoff: 2024-06
       Current date: 2026-04-24
    
       You are an AI assistant accessed via an API.
    • htrp 1 hour ago
      Can you really believe things that the model says? (A lot of prior model api pages say knowledge cutoffs of June 2024, maybe the model picks that up?)
      • czk 1 hour ago
        you cant but its pretty reproducible across api and codex and other agents so i just thought it was odd. full text it gives:

           Knowledge cutoff: 2024-06
           Current date: 2026-04-24
        
           You are an AI assistant accessed via an API.
        
           # Desired oververbosity for the final answer (not analysis): 5
           An oververbosity of 1 means the model should respond using only the minimal content necessary to satisfy the request, using
         concise phrasing and avoiding extra detail or explanation."
           An oververbosity of 10 means the model should provide maximally detailed, thorough responses with context, explanations, and
         possibly multiple examples."
           The desired oververbosity should be treated only as a *default*. Defer to any user or developer requirements regarding
         response length, if present.
    • BeetleB 1 hour ago
      I don't know why this keeps coming up. This has always been the least reliable way to know the cutoff date (and indeed, it may well have been trained on sites with comments like these!)

      Just ask it about an event that happened shortly before Dec 1, 2025. Sporting event, preferably.

      • czk 1 hour ago
        the model obviously knows things after the reported date but its just curious that it reports that date consistently

        could be they do it intentionally to encourage more tool calls/searches or for tuning reasons

    • swyx 1 hour ago
      can u test it on say who won the 2024 US election
      • ghurtado 1 hour ago
        I can't really think of a less reliable test for anything at all than making a random guess as to something that had about 50/50 odds to begin with

        Easiest Turing test ever...

      • WarmWash 1 hour ago
        Usually the labs do some kind of post training on major events so the model isn't totally lost.

        A better test is something like "what is the latest version of NumPy?"

        • bakugo 55 minutes ago
          That sort of test isn't super reliable either, in my experience.

          You're probably better off asking something like "what are the most notable changes in version X of NumPy?" and repeating until you find the version at which it says "I don't know" or hallucinates.

      • czk 1 hour ago
        with thinking off and tools disabled:

          Donald Trump won the 2024 U.S. presidential election.
      • redsocksfan45 43 minutes ago
        [dead]
    • bakugo 59 minutes ago
      Models don't know what their cutoff dates are unless told via a system prompt.

      The proper way to figure out the real cutoff date is to ask the model about things that did not exist or did not happen before the date in question.

      A few quick tests suggest 5.5's general knowledge cutoff is still around early 2025.

      • czk 58 minutes ago
        i wonder if they put an older cutoff date into the prompt intentionally so that when asked on more current events it leans towards tool calls / web searches for tuning
        • ssl-3 27 minutes ago
          I wonder if the cutoff date is the result of so many people posting about the date over time and poisoning the data. "Dead cutoff date theory," perhaps.

          Whatever it is, the cutoff date reporting discrepancy isn't new. Back when Musk was making headlines about buying/not buying Twitter, I was able to find recent-ish related news that was published well after the bot's stated cutoff date.

          ChatGPT was not yet browsing/searching/using the web at that point. That tool didn't come for another year or so.

      • MallocVoidstar 44 minutes ago
        OpenAI does tell the model the current date via API, so it's odd for them not to also tell the model its cutoff
      • soco 54 minutes ago
        Stupid question: wouldn't it then search the web for that event?
        • bakugo 53 minutes ago
          If you have web search enabled, sure. But if you're testing on the API, you can just not enable it.
  • throw03172019 1 hour ago
    Faster than anticipated because of Deepseek release?
    • XCSme 48 minutes ago
      Doubt it, DeepSeek v4 is quite underwhelming.
    • swyx 1 hour ago
      more like they wanted to release it yesterday but merely had some last min flags they wanted to hold off for
    • m3kw9 55 minutes ago
      Maybe but no one serious is using deepseek
    • brianbest101 1 hour ago
      [dead]
  • redsaber 1 hour ago
    not available for Github Copilot pro(only in pro+, business and enterprise), I am really now feeling the era of subsidized AI is over.
  • _pdp_ 33 minutes ago
    A very expensive model for API usage. Fine in codex I think.
  • pants2 1 hour ago
    Is anyone here actually using pro models through the API? I'd be very curious what the use-case is.
    • chadash 1 hour ago
      Yes. High value work where cost (mostly) doesn't matter. For example, if I need to look over a legal doc for possible mistakes (part of a workflow i have), it doesn't matter (in my case) whether it costs $0.01 or $10.00, since it's a somewhat infrequent event. So i'll pay $9.99 more, even if the model is only slightly better.
      • bogtog 1 hour ago
        I'm surprised I never heard people talking about using -Pro variants, even though their rates ($125-175/M?) aren't drastically larger than old Opus ($75/M), which people seemed to use
      • freedomben 1 hour ago
        Indeed, even just Terms of Service and Privacy Policy work. Infrequent enough that cost isn't an issue, but model quality absolutely is
    • ComputerGuru 1 hour ago
      Yes? The same reason you would use it via the tooling.
  • gigatexal 1 hour ago
    what's the real world comparison to opus 4.7 fellow coders?
  • pillefitz 1 hour ago
    Please consider the ethical aspects of giving money to OpenAI versus alternatives.
  • Jhonwilson 1 hour ago
    that is great news
  • benjiro3000 30 minutes ago
    [dead]
  • theo_park87 1 hour ago
    [dead]
  • rvnx 1 hour ago
    Very bad habit these safeguards. These "safety" filters are counter-productive and even can be dangerous.

    In my place for example, a lot of doctors are using ChatGPT both to search diagnosis and communicate with non-English speaking patients.

    Even yourself, when you want to learn about one disease, about some real-world threats, some statistics, self-defense techniques, etc.

    Otherwise it's like blocking Wikipedia for the reason that using that knowledge you can do harmful stuff or read things that may change your mind.

    Freedom to read about things is good.

    • NicuCalcea 1 hour ago
      > a lot of doctors are using ChatGPT both to search diagnosis and communicate with non-English speaking patients

      I think that's the problem. Who's going to claim responsibility when ChatGPT hallucinates or mistranslates a patient's diagnosis and they die? For OpenAI, this would at best be a PR nightmare, so that's why they have safeguards.

      • rvnx 25 minutes ago
        Adults bear responsibility for choices about their own lives. In fact, the more educated they are, the better choices they can make.

        A doctor who gets refused by ChatGPT doesn't stop needing to communicate with the patient; they fall back to a worse option (Google Translate, a family member interpreting, guessing). Refusal isn't safety, it's liability-shifting dressed up as safety.

        If there's no doctor, no interpreter, no pharmacist, just a person with a sick kid and a phone, then "refuse and redirect to a professional" is advice from a world that doesn't exist for them. The refusal doesn't send them to a better option; there is no better option, it's a large majority of people on this planet.

        Hell is paved of good intentions, but open-education and unlimited access to knowledge is very good.

        It doesn't change the human nature of some people, bad people stay bad, good people stay good.

        About PR, they're optimizing for not being the named defendant in a lawsuit or the subject of a bad news cycle, it's self-interest wearing benevolence as a costume.

        This is because harms from answering are punishable (bad PR, unhappy advertisers, unhappy investors, unhappy politicians / dictators, unhappy lobbies, unhappy army, etc); but harms from refusing are invisible and unpunished.

      • hellohello2 1 hour ago
        The doctor would be responsible.

        I had a choice better a doctor that used AI or not, I would much prefer one that did...

        • NicuCalcea 42 minutes ago
          The doctor would be responsible for the accuracy of their translation tool, something they can't verify but you expect them to use?
          • rvnx 24 minutes ago
            What's the alternative then ? (I had this real world scenario as a patient at emergency)
            • duchef 4 minutes ago
              We generally use translator telephone services. There is an entire industry for is - i.e. I used 'BigWord' today.
    • timedude 1 hour ago
      Yup, deliberately making the model retarded