PostHog vs Rollbar: A Hands-On Error Tracking Comparison for 2026

A release that did nothing but slow down one database query tripped up PostHog and Rollbar in exactly the same way. Each reported my months-old coupon bug as a brand-new error, because the slow query changed which framework frames sat under the crash, and both products count those frames when they group. The two tools disagreed on almost everything else.

PostHog is a product analytics platform with error tracking built in, next to session replay, logs, OpenTelemetry tracing and an AI assistant, all on one usage-based bill with a large free tier. Its error pages lean on those neighbors: a server error links to its trace, its logs and the user's recording.

Rollbar is a dedicated error tracker for the browser and the server. It skips performance and logs entirely and puts its effort into the release workflow: resolving in a version, naming the deploy that brought a bug back, and a page per version showing what changed.

I ran both on the same bookstore app, browser and server, through the same three releases, so this is a head-to-head throughout. Where I skipped a feature, like Rollbar's GitHub-based root cause analysis, the section says so.

What follows covers what each tool caught, how it explained it, how it grouped it, how it handled releases, and what it costs.

PostHog vs Rollbar: Results at a glance

These results come from an Express and Vite app with each tool configured from its own documentation, PostHog on its free plan and Rollbar on a trial. Different stacks or custom fingerprint rules could move several rows.

How I tested PostHog and Rollbar

monitoring-lab is my test bookstore, and its bugs are deliberate. Shoppers browse a Vite front end that calls an Express API on SQLite. Beside it, a stand-in price service fails on cue, and a report job runs every minute. Each tool connects through the same pair of adapter files, so the rest of the code never changes.

The failures each tool had to catch:

• In the browser: a TypeError from the wishlist button, an unhandled rejection from order tracking, and API calls that come back 404, 500 or 502.
• In the API: an unknown coupon crashing checkout, a missing book crashing its page, a handled out-of-stock error, 503s from the price service, and a recommendations promise nobody catches.
• In the job: failing sales report runs.

Two headless browser shoppers, alice and bob, sign in and shop. carol hits the API without a browser.

The releases

The interesting question in 1.2.0 is whether a tool tells you both things at once: checkout got slower, and something new is failing.

SDKs and test limitations

• Separate runs: Rollbar on October 22, PostHog on October 28, both with the same traffic script. Counts aren't comparable one to one.
• Rollbar's environments differ by tier: my storefront reports "production" and my API "development", which affects some Rollbar views.
• Untested AI: Rollbar's root cause analysis needs its GitHub app, which I didn't install.
• No alert delivery: neither tool had a channel connected.

Terms in each tool

Setup and onboarding

Both tools cover the browser and the server from npm, in one project. Each new account had a problem that stopped data until I found it.

PostHog: More products than you asked for, minus the one you need

PostHog asks for your goal first. "Find and fix issues" preselected product analytics, web analytics and session replay, and I had to add Error Tracking from the full list. Its AI install wizard doesn't list Express, so I followed the manual Node.js page:

The marked note matters for every Express app: errors caught by Express need setupExpressErrorHandler, or they never reach PostHog. Then three defaults got in the way. Headless Chromium was filtered out until I set opt_out_useragent_filter, session replay was switched off at the project level, and my older posthog-node needed an upgrade.

Rollbar: One SDK at a time, and a token to replace

Rollbar's picker shows one SDK's instructions at a time, so a full-stack app means a second trip through "Select different SDK":

The brand-new project's setup pages handed me tokens belonging to an old, deleted project. Data only started flowing after I created fresh ones under Project access tokens. The browser setup with replay comes down to one client:

import Rollbar from 'rollbar/replay';

const rollbar = new Rollbar({
  accessToken: import.meta.env.VITE_ROLLBAR_CLIENT_TOKEN,
  captureUncaught: true,
  captureUnhandledRejections: true,
  payload: { client: { javascript: { code_version: '<your_release>' } } },
});

The highlighted trigger records a replay whenever an occurrence is reported. The Replays setup page suggested a 3.0 release candidate, and 4.1.0 worked fine.

Worth turning on: in PostHog, switch on session recording and network capture in project settings on day one. In Rollbar, report deploys from your pipeline with the version, since suspected deploys and auto-resolve depend on them.

Setup comparison

Verdict: Tie. Each lost me time in a different way, and neither problem would recur once fixed. PostHog fits teams that want more than errors from one install, and Rollbar fits teams that want error tracking and replay with nothing extra to configure.

Error capture

Both tools put the browser and the server into a single list. The difference was in what slipped through and how each row described itself.

PostHog: Severity and owner on every row

PostHog's issues list puts occurrences, sessions and users on each row, with status, severity and assignee editable in place:

Severity was set automatically on some rows. One failure never showed up: the rejected recommendations promise. The app has its own listener for unhandled rejections, and in Node's default mode the PostHog SDK relies on the process crashing to see them. Two smaller oddities were the report job's location naming my adapter's span wrapper, and anonymous requests counting as a new user each time.

Rollbar: Every failure, but level only

After the first run, Rollbar's items list held 11 rows, six from the API and five from the storefront:

The recommendations rejection is there as item #3, and browser rows carry a replay icon. Rollbar shows a level on each item, with no handled or unhandled marker, so the handled out-of-stock error sits at the same weight as the crashes. Because my two tiers report different environments, the list and the People page treat them as separate halves of one app.

Error capture comparison

Verdict: Rollbar, narrowly. It caught every failure I planted, the rejection included. PostHog's rows are more useful for triage, and a team without its own rejection handler might never hit the gap. Rollbar fits teams that want nothing missed, and PostHog fits teams that triage by severity.

Source maps

Both tools needed uploads, since my storefront ran on a private host.

PostHog: Two CLI steps, and a release you didn't name

posthog-cli sourcemap inject writes IDs into the bundle, and sourcemap upload sends the maps. Afterwards the wishlist crash resolved to src/pages.js, but its earlier events stayed in a separate issue:

One bug now had two rows, because the fingerprint uses the resolved frames. The release attached to those maps was my git commit, since the inject step picks it from git unless you give it the release flags too.

Rollbar: Upload per version, and a function name

Rollbar takes maps through its API, keyed by the code_version the SDK reports, and a short script handled it per release. Here's how the wishlist crash looked afterwards:

Rollbar's top frame names the bookDetail function in src/pages.js, line 122, and the replay panel sits directly under the code. Rollbar recovered the function's name, and its maps belong to the version you report, with no git lookup involved.

Source map comparison

Verdict: Rollbar. Its maps attached to the version I named and produced one row per bug. PostHog's server source lines are a real plus, and they belong to the next section.

Debugging an error

The checkout crash from a bad coupon makes a fair test, since it starts in the browser and dies in the API.

PostHog: The code, the request's trace, and its logs

The server issue shows lines 143 to 157 of server.js with line 150 marked, read from the server's own files:

View trace opens that request's spans, and its Logs tab narrows to the lines written during it:

Three log lines belong to this one checkout, with nothing from other shoppers. What's missing is the request body on the event, and anything from the browser, which you reach by session ID.

Rollbar: Request values, a curl command and telemetry

Rollbar's Detail tab is built for server errors. It lists every request field and header with a Typicality column showing how often each value appears across occurrences, and it offers the request as a copyable curl command to replay it. Telemetry lists the last 100 console lines and HTTP calls.

On the server that telemetry belongs to the process, with no per-request scope. alice's payment error listed bob's and carol's activity too, so read it as what the server was busy with. The Related tab matches by title:

It lists other browser ApiError items, none of them the server crash behind the failed checkout. Rollbar has no tracing to join the two.

Debugging comparison

Verdict: PostHog. Code, trace and request-scoped logs on the issue explained the coupon crash fastest. Rollbar's Typicality and curl command are excellent for reproducing a server bug, and nothing in PostHog matches them. PostHog fits teams working across tiers, and Rollbar fits teams reproducing API failures by hand.

PostHog's trace stopped at the server's edge, and Rollbar could only suggest items with similar titles. My Better Stack test traced one storefront request across both tiers:

The browser's 30 spans and the API's 7 share one trace. You go from the shopper's click to the failing server code without a session ID or a title search.

Trace one request through browser and API

Session replay

Both tools record users. PostHog records whole visits, and Rollbar records around errors.

PostHog: Full recordings, once switched on

With recording enabled, an issue's Recording tab plays the visit at the moment the error fired:

alice's cursor is on "Add to wishlist". Console and network timings were captured by default, and I added headers and bodies. Page text was visible at the default privacy level. PostHog also offers AI recording summaries and a highlights scanner, which I didn't try.

Rollbar: Clips with linked items

Rollbar starts a recording when an occurrence fires and plays it inside the item. The event list beside the player is where it shines:

Network calls carry status and timing, clicks carry their CSS selector, and other Rollbar items from the same visit appear as links, like the order-tracking 404 here. My clips ran 0 to 15 seconds, and request bodies weren't part of them. Every account gets 1,000 replays a month.

Worth turning on: in PostHog, raise the privacy level or mask sensitive elements before recording real customers.

Replay comparison

Verdict: PostHog. A whole visit answers questions a 15-second clip can't reach. Rollbar's linked items are a clever touch, and its replay costs nothing extra at small scale.

Error grouping

At 1.0.0, both tools grouped every bug correctly. 1.2.0 changed that for both, in nearly the same way.

PostHog: Hidden frames still count

PostHog ignores message text, so charges for different amounts can share an issue. In 1.2.0, though, the new payment error landed in two issues:

Both throw at server.js:173. The other issue's fingerprint also holds two node:internal timer frames, which the page hides yet still uses. The coupon crash and the out-of-stock error each gained two sibling issues the same way. PostHog's remedy is Grouping rules, empty by default, or merging through each issue's Fingerprints panel.

Rollbar: Framework frames, and five "new" items

Rollbar split along the same seam. In 1.2.0 the payment error became items #13 and #14, one with framework frames and one without, and the coupon crash spread over three items. The version page counted the damage:

New (5) held one bug that was new and four that weren't. Rollbar offers Custom fingerprinting per project and Merge on items. Separately, it titled every out-of-stock occurrence after the first book that ran out.

Grouping comparison

Verdict: Neither. Both made one bug look like several after a release changed timing, which is the moment you most need an accurate count. Plan on writing a grouping rule in either tool for any Node.js backend.

PostHog and Rollbar both split the 1.2.0 payment bug on frames from Node and Express. In Better Stack, the same release produced one group:

Ten payment exceptions sit in that row, with the throwing code shown. The extra async frames from the slow query didn't produce siblings, so the new-error count stayed at one.

Group errors by your code

Releases and regressions

The 1.1.0 test was simple: mark the coupon bug fixed, leave the code alone, and ship.

PostHog: Automatic reopen, manual context

Resolving in PostHog takes one click and asks for no version. The first 1.1.0 events flipped the issue straight back to Active:

No label marks it as reopened, in the list or on the page. The Breakdown panel splits its events by app_version, which answered "did it come back in 1.1.0" once I looked. Resolving also offered to email the two signed-in users who'd hit the bug, a feature I haven't seen elsewhere. Releases themselves were awkward: they come from source map uploads, named after git commits unless you pass the flags at inject.

Rollbar: Fixed as of a version

In Rollbar, you can attach a version and a note when you resolve. When I resolved the coupon crash in 1.1.0 while the app still ran 1.0.0, it stayed resolved through 11 more events, since those came from the older version. Once 1.1.0 really ran, the item reactivated:

"Reactivated version: 1.1.0" and "Suspected deploy" link back to the deploy I'd reported. The version page put the bug under Reactivated (1), apart from everything still active.

Auto-resolve on deploy

Before deploying 1.2.0, I switched on the setting that resolves everything at each deploy, for the API's environment only:

The 1.2.0 deploy resolved all six backend items, fixed or not. Three came back during traffic and showed as reactivated on the 1.2.0 page. The payment error was tied to that deploy as its suspect too:

First version 1.2.0 and the deploy ID are on the item, so the question "what shipped this" has an answer on the page.

Release comparison

Verdict: Rollbar. Version-aware resolving, a suspected deploy and a page per version are a complete release review. PostHog reopened the bug reliably, but answering which release brought it back took a breakdown and some setup. Rollbar fits teams that ship on a schedule, and PostHog fits teams that think in users more than versions.

Both tools reopened the coupon bug, and in both lists the row simply read as active again. Better Stack marked it in the list when 1.1.0 shipped:

Only the returning bug carries the red "Reoccurred" tag. You catch it while scanning the list, before you'd think to open a version page.

Flag regressions where you triage

Performance monitoring

1.2.0 slowed checkout's book query to seconds. One of these tools could see that.

PostHog: Percentiles by version

PostHog's tracing comes from the OpenTelemetry SDK. Tracing → Operations with the version facet set to 1.2.0 showed the problem:

POST /checkout reached 4.76 s at p95 and SELECT book for checkout 2.93 s. With the filter on 1.1.0, checkout's p95 was 4.21 ms. A slow GET /search also stood out, but its gap sat in uninstrumented code and was there on every version.

Rollbar: Nothing to measure

Rollbar has no tracing, RUM or performance product. Checkouts in 1.2.0 ran three to five seconds each, and nothing in Rollbar changed to show it. Replay events show request durations, but only around errors and one visit at a time.

Performance comparison

Verdict: PostHog. It found the slow query in two clicks. With Rollbar you need a separate tracing tool for this.

Logs and querying

PostHog stores logs. Rollbar stores errors and lets you query them.

PostHog: Logs with patterns and live tail

Over OpenTelemetry, the app's log lines flowed into PostHog's logs product, about a thousand in the first hour, filterable by level, service and host:

Patterns, grouping and live tail sit beside the viewer, and the same lines show up on each trace. PostHog's SQL works across events too, and I used it to check raw exception data.

Rollbar: RQL over occurrences

Rollbar's telemetry includes console lines, so my slow-query warnings appeared inside item timelines with no search. RQL is an SQL-like language over occurrences, on the Advanced plan. This query, which I ran during the test, counts occurrences per item:

SELECT item.counter, item.title, count(*)
FROM item_occurrence
GROUP BY item.counter, item.title

It follows SQL's GROUP BY rules strictly, and each new query starts with no project selected.

Logs and querying comparison

Verdict: PostHog. It stores and searches logs and joins them to requests. RQL is a strong tool for slicing errors, though logs still need a home elsewhere.

PostHog joined logs to traces, and Rollbar kept console lines as unsearchable telemetry. Better Stack's live tail filtered to the failing 1.2.0 checkout in my test:

Filtering on that request's trace keeps its slow-query warning and drops everyone else's traffic. The same lines stay searchable long after the incident.

Search logs alongside your errors

Alerts

No alert reached me from either tool, so this compares setup only.

PostHog: Rules ready, destination missing

The issues list carries a banner until you connect Slack, Teams, PagerDuty or another destination:

New, reopened and spiking issues are the triggers, and configuration adds spike detection, rate limits, assignment and severity rules.

Rollbar: Email rules from day one

A new Rollbar project comes with 11 email rules already active. They cover new and reactivated items, deploys and new versions, plus a daily digest and a rule for sudden bursts. Slack, Jira, GitHub, PagerDuty, Opsgenie, Datadog and webhooks are the other channels.

Alerts comparison

Verdict: Not compared. Nothing was delivered. On paper, Rollbar alerts the moment you install it, and PostHog waits for a destination.

AI-assisted debugging

PostHog AI lives inside the product and can also hand prompts to outside tools. Rollbar's Root cause & fix connects to your GitHub repositories, and I didn't connect one, so only PostHog was tested.

PostHog: Right on the mechanism, wrong on the details

Open Fix prompt on an issue can send an explain or fix prompt to PostHog AI or to an editor assistant:

On the coupon crash, PostHog AI explained the null access correctly and then invented coupon codes my app doesn't use. On the 1.2.0 payment issues, it blamed the split on amounts in the message, reconstructed code it couldn't see, and never linked the failures to the release or the slow query.

Rollbar: Code-aware, once connected

Root cause & fix lists related occurrences, then asks for a GitHub connection to read your code. Each run uses AI credits: the trial came with some, and paid tiers begin at 4,000 monthly. Rollbar also has an assistant in the RQL editor. I tried neither.

AI comparison

Verdict: Not compared. PostHog AI was quick and too willing to guess without the code. Rollbar's design addresses that gap, and I can't say how well it works.

PostHog AI filled gaps with guesses, and Rollbar's analysis waits on a GitHub connection. Better Stack's AI SRE answered the 1.2.0 question in my test from telemetry alone:

It pinned the slowdown on checkout's query and found 10 rejected charges among 48, all from 1.2.0. The investigation ran about four minutes for $0.49, and it's reachable over MCP from your editor as well.

Let AI SRE explain a bad release

Pricing

PostHog meters each product separately above a shared monthly free tier. Rollbar meters error occurrences and replays, with AI credits on paid plans.

I checked both pages on November 12, 2026. Rollbar's paid plans showed a dash in place of a price, so its figures are from my October 23 reading, and PostHog's per-unit exception rate is from October 28. Confirm both before buying.

Free plans and trials

Rollbar's trial runs the Advanced plan for 14 days. PostHog has no trial, since the free plan is the starting point.

Entry-level paid plans

What costs extra

Comparing the actual cost

A small app with a few thousand errors fits both free plans, but PostHog's covers 20 times the errors, five times the recordings, plus logs and tracing. Rollbar's paid tiers start cheap, under $15 a month, and stop at your limit by default, so a noisy release can't run up a bill.

PostHog's spend grows across several meters at once, so set caps per product before your first bad deploy. For a page-view model to compare against, see our PostHog vs TrackJS comparison, and for Rollbar's against the same, our TrackJS vs Rollbar comparison.

Verdict: PostHog. Its free tier covers far more ground. Rollbar is the cheaper paid error tracker if errors are all you buy.

Full feature comparison

Which should you choose?

The overlap is error tracking and replay. Past that, PostHog adds observability and Rollbar adds release discipline.

Choose PostHog if errors are one signal among many

• You want the trace and logs next to the error. One click took me from the coupon crash to its spans and the three log lines from that request.
• Performance regressions matter. Percentiles by version found the 1.2.0 query without another tool.
• You'd like it free for now. The free tier spans errors, recordings, logs and tracing.

The trade-offs: grouping that counts hidden frames, releases tied to git unless configured, alerts that need a destination, and an AI that guesses. For PostHog next to an error tracker with deeper release features, see our Sentry vs PostHog comparison.

Choose Rollbar if each release gets reviewed

• You resolve against versions. Resolve in 1.1.0, see it reactivate with a suspected deploy, and read the version page.
• You reproduce API bugs by hand. Typicality and the curl command shorten that loop.
• You want alerts without setup. Eleven email rules are live on day one.

The trade-offs: no tracing or logs, short replays, process-wide server telemetry, and grouping that needs fingerprint rules. Our Sentry vs Rollbar comparison puts it against a tool that adds tracing.

FAQ

Can PostHog resolve an error in a specific version?

No. PostHog's Resolve has no version option, and any new event reopens the issue. Its Breakdown panel shows which version the new events came from.

Does Rollbar have performance monitoring?

No. Rollbar has no tracing, RUM or APM. Replays show request durations around errors, and that's the only timing it keeps.

Why did both tools create new errors for old bugs in 1.2.0?

Both include framework frames under your code in their fingerprints. The slow query in 1.2.0 changed which Express and Node frames appeared, so the same crash got new fingerprints. Grouping rules in PostHog or custom fingerprinting in Rollbar fix it.

Which has the better free plan?

PostHog's, by a wide margin. It allows twenty times as many errors and five times as many recordings, and adds logs, against Rollbar's 5,000 occurrences and 1,000 replays.

Final thoughts

PostHog and Rollbar both caught every bug that mattered and both stumbled on the same grouping trap. Where they part ways is what surrounds the error. PostHog puts the trace, the logs and the recording around it. Rollbar puts the version, the deploy and the release review around it.

So the decision is which question you ask first after a bad deploy. If it's "why is this slow and what did this user hit", PostHog answers it without another tool. If it's "which deploy did this and what else came back", Rollbar answers it without any setup beyond reporting deploys.

Whichever you pick, write a grouping rule before your next release changes the timing.

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